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All living organisms including plants and animals, respond and react to environmental factors or stimuli., The method of reacting to stimuli is not similar in, plants and animals. They react to stimuli in different, ways. For example, plants bend towards light but, animals do not bend towards light. The animal, Amoeba react to the presence of food by moving, towards the food particle. The animals can react to, stimuli in many different ways because they have a, nervous system and an endocrine system involving, hormones. The plants, however, react to stimuli in a, very limited way. This is because the plants do not, have a nervous system like the animals have. The, plants use only the hormones for producing reaction, to external stimuli., The working together of the various organs of an, organism in a systematic manner so as to produce a, proper response to the stimulus, is called, coordination. There is a necessity to develop some, system for control and coordination of various body, organs. In multicellular organisms, specialized tissues, are used for control and coordination activities., Control and coordination in animals are provides by, nervous, muscular and endocrine system. Chemical, coordination is seen in both plants and animals and is, responsible for growth and development., CONTROL AND COORDINATION IN PLANTS, Plants, like animals, need internal coordination if their, growth and development is to proceed in an orderly, manner. In plants, control and coordination is not as, highly developed as in animals. Plants cannot think,, analyze or memorize as human beings because they, lack brain and other parts of nervous system., However, plants respond to external stimuli like light,, touch, gravitational force and other stimuli. Plants, in, fact, show two different types of movements in, response to various stimuli. One type of movements, are independent of growth (e.g., movement of leaves, of 'touch-me-not' plant, also called chhui-mui or, 'sensitive plant', in response to touch). Other types of, movements are dependent on growth (e.g.,, directional movement of seedling with root, downwards and stem coming .up). Both these types, , of movements are affected by the action of plant, hormones (phytohormones). In other words, plants, coordinate their responses against environmental, stimuli by using hormones. Plants, thus, possess only, chemical coordination. The mode of action of, hormones in plants is different from that in animals., In plants, the hormones coordinate their behavior in, two ways:, (i) Affecting the growth of the plant and as a result, part of the plant shows movement, and, (ii) Affecting the shape of plant cells by changing the, amount of water in them (turgor changes), resulting in, swelling or shrinking. Thus, growth and movements in, plants are regulated by both external (environmental, stimuli) and internal (hormones) factors., PLANT MOVEMENTS, The movements in plant are not as apparent as in, case of animals. Plants show two different types of, movements:, (i) Movements independent of growth (Nastic, movements)., (ii) Movement due to growth (Tropic movements or, tropism)., Nastic movements, These are non-directional induced variation, movements that occur due to turgor changes. These, reveal immediate response to stimulus but do not, involve growth. Nastic movements include, seismonastic and nyctinastic movement., (i) Seismonastic movements, Such movements occur in response to touch (shock)., These movements are very quick and are best seen in, 'touch-me-not' plant (Mimosa pudica), also called, 'Chhui-mui' or 'Lajwanti' or 'sensitive plant'. As the, 'touch-me-not'plant responds to touch stimulus, this, phenomenon is also commonly called thigmonasty., (ii) Nyctinastic movements, The movements involving the diurnal variation in the, position of flowers and leaves of many plants in day, and night are called nyctinastic or sleep movements.

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Nyctinastic, movements, include, photonastic, movements and thermonastic movements., (a) Photonastic movements: If the diurnal variations, in the position of plant parts (e.g., flowers and leaves, of plants) are caused by the light stimulus, such nondirectional movements are called photonastic, movements. Example is dandelion flower. It opens up, in the morning in bright light and closes in the evening, when the light fades., (b) Thermonastic movements: If the diurnal, variations in the position of plant parts (e.g., flowers, and leaves of plants) are caused by the change in, temperature of the surroundings, such nondirectional movements are called thermonastic, movements., , (iii) Hydrotropism is the movement of a part of the, plant in response to water., (iv) Chemotropism is the movement of a part of the, plant in response to a chemical stimulus. If the plant, part shows movements or growth towards the, chemical, it is called positive chemotropism and if the, plant part shows movements or growth away from, the chemical, it is called negative chemotropism., For example, the growth of pollen tube towards a, chemical which is produced by an ovule during the, process of fertilization in a flower is an example of, positive chemotropism., , Tropic movements or Tropisms, Directional movements or orientations of specific part, of a plant in response to external stimuli are called, tropisms or tropic movements. Tropic movements are, very slow. The movement of the plant part can be, either towards the stimulus or away from the, stimulus., • If the movement of the plant part is towards the, stimulus, it is termed as positive tropism., • If the movement of the plant part is away from, the stimulus, it is termed as negative tropism., , To show response of plant parts to light, (phototropism), Materials required: Conical flask, water, wire mesh, 23 freshly germinated bean seeds, cardboard box open, from one side., Procedure: Take a conical flask- fill it with water., Cover the neck of the flask with a wire mesh. Now,, keeps two or three freshly germinated seeds on the, wire mesh. Keeps this flask in the cardboard box, (open from one side) in such a manner that the open, side of the box faces light coming from the window., Observe the plant after few days. Now, turn the flask, so that the shoots are away from light and the roots, towards light. Leave it undisturbed in this position for, a few days and then observe the difference if any., , Types of tropism, Light, force of gravity, chemical substances and water, are the four common stimuli in the environment to, which the plants respond. The responses of plants to, these stimuli are termed as (i) phototropism (light), (ii), geotropism (gravity), (iii) chemotropism (chemical), and (iv) hydrotropism (water) respectively., (i) Phototropism is the movement of a part of the, plant in response to light. Shoots generally grow, towards light and are said to be positively, phototropic, while roots grow away from light and are, said to be negatively phototropic., (ii) Geotropism is the upward and downward growth, of shoots and roots in response to the pull of earth or, gravity. If the plant part moves in the direction of, gravity, it is called positive geotropism. Alternatively,, if the plant part moves against the direction of gravity,, it is termed as negative geotropism., , Observations: (i) When the flask is placed in the, Observation: (i) When the flask is placed in the, cardboard (open from one side) in a manner that the, open side of box face light coming from the window,, the shoots of freshly germinated seeds have shown, growth by bending towards light (positive phototaxis), , 2

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and rots have shown growth by bending away from, light (negative phototaxis)., (ii) When the flask was turned in a manner that the, shoots; moved away from light and roots moved, towards light, it was found that after few days shoots, have again grown by bending towards light and the, roots have grown again by bending away from light., Towards light and the roots have grown again by, bending -away 'from: light., Conclusion: This experiment, therefore, shows that, the shoots of plant respond by showing growth, movement towards light (positive phototropism) and, roots of plants respond by showing growth movement, away from light (negative phototropism.), To study the effects of gravity (geotropism)., Materials required: Small young potted plant,, transparent bottle containing mineral solution, stand., Procedure 1: Transfer a small young potted plant in, the transparent bottle containing mineral solution., Observe the growth of roots and shoot of the plant, Observation 1: Young roots grow downward towards, gravity and the young shoot grows upward against the, gravity., Procedure 2: Fix the bottle upside down with the help, of stand and observe the growth of shoot and root., Observation 2: Once again the roots start growing, downward towards the gravity and the shoot starts, growing upward against the gravity, Conclusion: This experiment, therefore, concludes, that roots are positively geotropic while shoots are, negatively geotropic., , Observation: In trough A, the root of seedling is, straight. However, in trough B, the root of seedling is, bent towards the direction of clay pot containing, water., Conclusion: In trough A, soil is watered uniformly, daily. Therefore, the root of seedling gets water, equally from all sides. Hence, it grows straight, downwards. On the other hand, in trough B, the root, of seedling only gets water that oozes out of clay pot, buried in soil. Therefore, in trough B, the root of, seedling grows by bending towards the direction of, clay pot., This experiment, thus, reveals the response of root of, seedling (plant part) towards water (hydrotropism)., , 1., Ans., , 2., , Ans.:, , To show the response of plant parts to water, (hydrotropism), Materials required: Plant a tiny seedling in each, trough A and trough B. Now, place a small clay pot in, the soil in trough B. Water the soil daily in trough A, uniformly. However, in trough b, put water daily in, clay pot only., After few days carefully dig up the seedlings in both, the glass troughs without damaging their roots., , 3., Ans.:, , 3, , Design an experiment to demonstrate, hydrotropism., 1.Take a tin box with a hole at the bottom, 2. Fill it with moist saw dust., 3. Sow some gram seeds in it. Keep the tin, box in a tilted position, 4. When seeds start germinating, water the, saw dust only in the lower side of tin box., It is seen that the roots of germinating seeds, (radicle) moves towards the wet saw dust., This shows that roots are positively, hydrotropic., How is the movement of leaves of the, sensitive plant different from the movement, of a shoot towards light?, The movement of leaves of sensitive plant is, neither towards, nor away from the stimulus, like touch, etc. It is a non- directional, movement, (nastic, movement),, while, movement of shoot is towards the stimulus, like light, etc., It is a directional movement (tropic, movement)., Define thermonastic movements., If the diurnal variations in the position of, plant (e.g.., flowers and leaves of plants) are, caused by the change in temperature of the, surroundings, such non - directional, movements, are, called, thermonastic, movements.

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PLANT HORMONES OR PHYTOHORMONES, , of stomata, falling of leaves, fruit growth, fruit, ripening, ageing in plants, tropisms and nastic, movements, etc. are controlled by various, phytohormones. These are synthesized at places away, from where they act and simply diffuse to the area of, action., Types of phytohormones, The major types of plant hormones which are, involved in the control and coordination in plants are, as follows:, , Phytohormone is a chemical substance which is, produced naturally in plants and is capable of, translocation and regulating one or more, physiological processes when present in low, concentration. Plant hormones help to coordinate, growth, development and responses to the, environment. Plant hormones are also known as plant, growth substances or plant growth regulators. Besides, growth, various other activities such as promotion of, dormancy, breaking of dormancy, opening and closing, Table: Plant hormones and their functions, , Plant hormones, Functions, 1. Auxins, These promote cell enlargement and cell differentiation in plants., (Naturally occurring auxin is These promote stem and fruit growth., iodole 3-acetic acid), These regulate important plant growth movements, i.e., tropisms., These induce pathenocarpy (i.e., the formation of seedless fruits without, fertilization) in number of plants., 2. Gibberellins, These promote cell enlargement and cell differentiation in plants in the, (Gibberellic acid), presence of auxins. These also promote growth in stems and fruits., Rosette plants (i.e., plants that show profuse leaf developments but, reduced internode growth) show bolting and flowering when treated with, gibberellins., These also induce parthenocarpy in many plants., 3. Cytokinins, These promote cell division in plants., These play vital role in the morphogenesis in plants. These help in breaking, the dormancy of seeds and buds., These delay the ageing in leaves., These promote the opening of stomata., These also promote fruit growth., 4. Ethene, (Ethylene), , 5. Abscisic acid, (ABA), , It promotes growth and ripening of fruits., It helps in breaking the dormancy in buds and seeds., It stimulates the formation of separation layer (abscission zone) in leaves,, flowers and fruits., It promotes yellowing and senescence of leaves., It promotes the dormancy in seeds and buds and thus inhibits growth., It also promotes the closing of stomata and thus affects wilting of leaves., It also promotes the falling of leaves (abscission) and senescence in leaves., Ans.:, 6., , 4., Ans.:, , 5., , What are plant hormones?, plant hormones are chemicals present in, plants which help to coordinate growth,, development and responses to stimuli and, environment., For, example,, auxins,, gibberellins, cytokinins, abscisic acids are, different plant hormones., Give an example of a plant hormone that, promotes growth., , Ans.:, , 4, , Auxin is the plant hormone that helpls in cell, growth and elongation., How do auxins promote the growth of a, tendril around a support?, When tendrils come in contact with any, support, the part of the tendril in contact with, the object does not growl as rapidly as the, part of the tendril away from the object. This, is caused by the action of auxin hormone. Less, auxin occurs on the side of contact as, compared to the free side. As a result, auxin

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7., Ans.:, , 8., Ans.:, , promoters growth on the free side and the, tendrils coil around the support., Name various plant hormones., The various plant hormones are auxins,, gibberellins, cytokinins, ethylene and abscisic, acid., Why plant hormones are also called plant, growth regulators?, Plant, hormones, or, phytohormones, (‘Phyto’means plant) are naturally occurring, organic chemical substances present in plnats, which bring about control and coordination of, various activities in them. They do so by, controlling one or the other aspect of growth, of the plant. Therefore, plant hormones are, also known as plant growth substances or, plant growth regulators., , nervous system. But in higher animals (the, vertebrates) the coordination takes place through, both the nervous system as well as the hormonal, system., The nervous system is composed of specialized cells, called neurons (nerve cells) which exercise control by, sending electrical signals called nerve impulses. The, nervous control is speedy and flexible but its effect is, localized., The endocrine system consists of specialized glands, (endocrine glands) which bring about control by, sending chemical messengers termed hormones. The, hormonal control is usually slow acting and its effect, is diffuse., NERVOUS SYSTEM, Except sponges, all multicellular animals possess, simple or complex nervous system. In all these, animals, nervous system is comprised of nervous, tissue having specialized cells called neurons or nerve, cells to respond to stimuli and coordinate animals', activities., Nerve cells or neurons are, in fact, the structural and, functional units of nervous system. In higher, multicellular animals, the nervous tissue consists of, nerve cells or neurons, nerve fibres, bundle of nerve, fibres forming nerves, packing cells (neuroglia),, ependymal cells and neurosecretory cells., , Role of auxin in phototropism, Plants respond to light by showing growth movement, towards light (phototropism). This growth movement, of the plant part (stem) is caused by the action of, auxin hormone. The auxin hormone is synthesized by, the meristematic tissue at the tip of the stem (or tip, of the shoot). It is illustrated below:, (i) Auxin diffuses uniformly down the stem in plant, kept in the open and receiving sunlight from above., Due to presence of auxin equally on both the sides,, the stem grows up straight because both the sides of, the stem show growth at the same pace (Figure A)., , Structure of neuron, The units which make up the nervous system are, called nerve cells or neurons. Neuron is the largest, cell in the body. It carries messages in the form of, electrical signals called nerve impulses. Neuron is and, elongated branched cell having three components –, cell body dendrites and axon, (i) Cell body or Cyton: Cell body is like a typical cell, containing a central nucleus and surrounding cytoplasm. Around the nucleus there are granules called, Nissl’s grnules. The cytoplasm has mitochondria, Golgi, apparatus, neurofibrils: neurotubules. Cell body is, concerned with metabolic maintenance and growth. It, also receives nerve impulses from dendrites and, transmits them to axon., (ii) Dendrites: Dendrites are several short, tapering,, much branched protoplasmic processes stretching out, from the cell body of a neuron. They receive sensation, or stimulus, which may be physical, chemical,, mechanical or electrical. The stimulus is passed onto, cyton., (iii) Axon: Axon is the longest part of the neuron. It is, a single, elongated fibre arising from one side of, cyton. It conducts impulses away from the cell body., The axon endings are highly branched and the, , Fig. Effect of auxin on the growth of a plant in response to light (Phototropism), , (ii) The second plant received light only from one side., In this case, the auxin hormone moved from the tip of, stem and concentrated more on the side not receiving, light (shady side, i.e., the side of stem away from, light). Due to presence of more auxin hormone, the, shady side of stem grew faster than the side of stem, receiving light. As a result, the stem bent towards the, direction of light., CONTROL AND COORDINATION IN ANIMALS, In animals two kinds of coordination — nervous and, chemical — are present. The nervous coordination is, brought about by the nervous system and the, chemical coordination by hormones. In lower animals, like Hydra and insects, coordination is through the, 5

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terminal branches are called terminal arborizations., Axon terminals are often knob-like and these may end, in nerve fibres (forming neuromuscular junction) or, glands or form synapses with dendrites of other, neurons., Axon is covered with one or two sheaths. Sheathed, axon is termed nerve fibre. The cell membrane of the, axon is called axolemma and its cytoplasm is termed, axoplasm. It lacks Nissl's granules. However,, neurofibrils are present. The single sheath present, over the axon is made of Schwann cells and is called, neurilemma. The axon has an insulating and, protective sheath of myelin around it. Nerve fibres, (axons) having myelin sheath are termed myelinated, nerve fibres and those without this sheath are termed, non-myelinated nerve fibres. Myelinated nerve fibres, conduct impulses more efficiently than nonmyelinated nerve fibres. At intervals, myelinated, nerve fibres possess unmyelinated areas called nodes, of Ranvier., Neurons transmit messages in the form of nerve, impulses. They have following special properties:, (i) They do not divide., (ii) From shortly after birth, new neurons do not, develop., (iii) They are not repaired, when injured., (iv) They use only glucose as a respiratory substrate., (v) They die if deprived of oxygen for over five, minutes., , and it is thought that the impulse is transmitted, across the synapse by chemical means., , At the synapse, axon terminal comes in close, proximity to the dendron terminal of next neuron., Axon terminal is expanded to form presynaptic, knob. On the other hand, the dendrite terminal forms, post-synaptic depression. In between the two, lies a, narrow fluid filled space called synaptic cleft. As the, nerve impulse reaches the presynaptic knob, the, synaptic vesicles get stimulated to release, neurotransmitter in the synaptic cleft. The, neurotransmitter molecules diffuse across the gap to, come in contact with post-synaptic membrane. In this, way, nerve impulse passes across the gap come in, contact with post – synaptic membrane. In this way,, nerve impulse passes across the minute gap to, stimulate dendron of other neuron. The synapse acts, as a one-way valve to conduct impulse in one, direction only. This is so because chemical substance, called neurotransmitter is secreted only on one side, of the gap i.e., on axon's side. It carries impulse across, the synapse and passes it to the dendron of the other, neuron. In this way, impulses travel across the, neurons only in one direction, i.e., from axon of one, neuron to dendron of other neuron through a, synapse., Types of neurons, The neurons are of three types: (i) sensory (receptor), neurons, (ii) motor (effector) neurons, and (iii), relaying (connector) neurons., (i) Sensory (receptor) neurons: These often occur in, sense organs, and receive stimuli by their dendrites., The sensory neurons transmit impulses towards the, central nervous system (brain and spinal cord), through their axons., (ii) Motor (effector) neurons: The dendrites of these, neurons synapse with axons of sensory neurons in, central nervous system. They transmit impulses from, central nervous system towards effectors (muscles or, glands). The latter respond to stimuli., (iii) Relaying (connector) neurons: These occur in the, central nervous system (brain and spinal cord). These, , Synapse, Synapse is the functional junction between neurons. It, is the point of contact between the terminal branches, of the axon of one neuron with the dendrites of, another neuron. There is no Mitochondrion., Presynaptic cytoplasmic connection between the two, 6

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serve as links between sensory and motor neurons for, distant transmission of nerve impulses., SENSORY RECEPTORS, All higher chordate animals (vertebrates) receive a, variety of external stimuli through specialized neurons, termed sensory receptors or sensory neurons. These, sensory receptors may be simple in structure or most, complex sense organs., These are cell or group of cells specialized to detect a, particular stimulus and to initiate the transmission of, impulses via the sensory nerves., The eyes, ears, nose, tongue and skin all contain, specific receptors responding to external stimuli., There are five receptors or sense organs through, which the animals receive stimuli or external, informations. These receptors are photoreceptors for, light (eyes), photoreceptors for sounds (ears),, gustatory, receptors, for, taste, (tongue),, olfactoreceptors for smell (nose) and thigmoreceptors, for touch (skin). The receptors pass information to the, brain. The brain transmits motor impulses to, appropriate effectors (muscles or glands) which, produce suitable responses., , Reflex are: It is the pathway taken by the nerve, impulses and responses in a reflex action, i.e., from, the receptor organs like skin to the spinal cord and, from the spinal cord to the effector organs like, muscles., Some common examples of reflex action are:, - Blinking of eyes in response to a foreign particle, that has entered the eye. - Sneezing or coughing,, if any unwanted particle enters the nose or, throat., - Watering of mouth at the sight of tasty food., - Immediate withdrawal of hand if a person, touches a hot object unknowingly., - Withdrawal of the leg by a person walking bare, feet if happens to step on a nail., Advantages of reflex action:, (a) Enables the body to give quick responses to, harmful stimuli and thus protects our body., (b) Minimises the overloading of brain., (ii) Voluntary actions: These are the actions which, need thinking and are performed knowingly, i.e., are, controlled by conscious thought. In each voluntary, action, the animal exercises its choice so that the, same stimulus may receive different responses at, different times depending upon the situation. For, instance, on seeing a snake in the way, one may run, away on first occasion or call for help on secondoccasion or try to kill it to save himself on the third, occasion. All such actions are voluntary actions that, are controlled by cerebellum part of hind brain., Similarly, walking in a straight line, riding a bicycle,, picking up a pencil are also voluntary actions, controlled by cerebellum. This part of the brain is, responsible for precision of voluntary actions and, maintains the posture and balance of the body., (iii) Involuntary actions: These are not under the, control of the will of an individual and are automatic, response to a stimulus which is not under the, voluntary control of the brain. Such actions are meant, for controlling and coordinating the functioning of, internal organs. Many of these involuntary actions are, controlled by the mid brain and hind brain. Regular, beating of heart, blood pressure, movements of, diaphragm during normal respiration, peristaltic, movements in the oesophagus, salivation, vomiting,, , REFLEX ACTIONS, INVOLUNTARY AND VOLUNTARY, ACTIONS, Specific change in the environment evokes an, appropriate response in the form of movement/, action, in, all, living, organisms., Such, movements/actions in these organisms are carefully, controlled. Animals perform three types of actions., These actions are: reflex actions, voluntary actions, and involuntary actions., (i) Reflex action: It is defined as an unconscious,, automatic and involuntary response of effectors, i.e.,, muscles and glands, to a stimulus, which is monitored, through the spinal cord. The journey (a - d) of reflex, action is called reflex arc., (a) Receptor organ like skin perceives the stimulus, and activates a sensory nerve impulse., (b)Sensory, organ, carries, message, in, Spinal cord (CNS) Message to brain the form of, sensory impulse to the spinal cord., (c) The spinal cord acts as modulator. The neurons of, spinal cord transmit the sensory nerve impulse to, motor neuron, (d) Motor nerve conducts these impulses to the, effectors like leg muscles which responds by pulling, back the organ away from the stimulus., , 7

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movement of the internal viscera etc. are all, involuntary actions and are controlled by hind brain., , muscular activities,, hearing and sight., For example,, , touch,, , smell,, , temperature,, , HUMAN NERVOUS SYSTEM, Nervous system in humans consists of three parts:, (i) Central nervous system (CNS) consisting of brain, and spinal cord. The brain and spinal cord receive, information from all parts of the body and integrate it., (ii) Peripheral nervous system (PNS) consisting of, nerves that arise from brain (cranial nerves) and from, spinal cord (spinal nerves). Through the nerves, the, nervous system communicates with the muscles., (iii) Autonomic nervous system (ANS) made up of, parasympathetic and sympathetic nervous systems., Though connected with the CNS, it works, independently and regulates involuntary activities of, the body like heartbeat, and peristaltic movements of, alimentary canal., , -, , Occipital lobe is the region for sight, i.e., visual, reception., - Temporal lobe is the region for hearing i.e.,, auditory reception., - Frontal lobe is the region for speech, facial, muscular activities and higher mental activities., - Parietal lobe is the region for taste, smell, touch, and conscious association., The cerebral hemispheres have an outer region of, densely packed nerve cells called cerebral cortex. This, is the region of various kinds of activities. These are, broadly classified into three areas — the sensory, areas, the motor areas and the association areas. The, sensory areas receive impulses from receptors and, register impressions of what we hear, see or feel. The, motor areas transmit impulses to various organs and, control voluntary movement like those of limbs and, face. The association areas give the ability to register, impressions and respond by interpreting past, experiments. These are associated with hunger,, memory, learning, reasoning and intelligence., Cerebrum, thus, is the most important part of the, brain as this is the seat of mental abilities, memory,, reasoning, speech and consciousness., (b) Olfactory lobes: The anterior part of the brain is, formed by a pair of short club-shaped structures, the, olfactory lobes. Each lobe consists cerebral, hemisphere and are, therefore, only visible in the, ventral view of the brain. A pair of olfactory nerves, arises from the olfactory lobes. Olfactory lobes are, concerned with the sense of smell., , Central nervous system (CNS), The CNS consists of brain and the spinal cord. The, brain and the spinal cord are protected by the, skeleton-brain by the cranium and spinal cord by the, vertebral column., Brain, Brain is the highest coordinating centre in the body. It, is situated in the cranial cavity of the skull in the head, region of the body. The bones of cranium or brain box, protect this delicate organ from mechanical injury., Inside the box, the brain is contained in a fluid-filled, balloon which provides further shock absorption., The brain is soft, whitish organ. It weighs 1.2 - 1.4 kg, and forms about 98% of the weight of the whole, central nervous system. It has about 100 billion, neurons (nerve cells). Brain is surrounded by three, membranes called meninges which provide protection, to it. The space between these three meninges is, filled with cerebrospinal fluid which protects the brain, from mechanical shocks., The brain is broadly divided into three regions: Fore, brain, mid brain and hind brain., (i) Fore brain (prosencephalon): Fore brain includes, cerebrum (cerebral hemispheres), olfactory lobes and, diencephalon. Fore brain is the main thinking part of, the brain., (a) Cerebrum:It the largest part of the brain and is, proportionately larger in humans than in any other, animal. It consists of two cerebral hemispheres (right, and left) joined together by a broad curved thick band, of nerve fibres called corpus callousum. Each cerebral, hemisphere is divided into four lobes. These lobes, control different activities of the body like those of, , 8

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1. It is the part of fore, brain., 2. It is the largest part, constituting 80% of the, brain., 3. It forms the front,, superior and lateral, sides of the brain, 4. It has two parts called, cerebral hemispheres., , It has three parts: two, lateral, cerebellar, hemispheres and one, central vermis., 5. It has two cavities Cavity is nearly absent., called lateral ventricles., 6. Cerebrum is the seat of Cerebellum coordinates, intelligence, and muscular activity., memory., 7. It controls movements, It maintains equilibrium, speech, sight, smell, of the body., taste,, hearing,, intelligence, etc., , (c) Diencephalon: It lies on the inferior side of the, cerebrum and thus is visible in the ventral view of the, brain. Its roof is called epithalamus, sides are called, thalami and its floor is termed hypothalamus., Diencephalon has a narrow cavity called third, ventricle. Hypothesis (pituitary) is attached by a stalk, or infundibulum to the hypothalamus region., Hypothalamus has control centres for hunger/ thirst,, fatigue, sleep, body temperature, sweating and, emotions. It secretes neurohormones which regulate, the secretions of anterior lobe of pituitary., (ii) Mid brain (Mesencephalon): It connects the fore, brain to hind brain. It is significantly small region. It, consists of two fibre tracts called crura cerebri and, two swellings called superior and inferior colliculi on, each side. The fibrous tracts, i.e., crura cerebri, connect hind brain with the fore brain. The four, swellings of both sides are together known as corpora, quadrigemina. The two superior colliculi have centres, for auditory reflexes. The mid brain controls reflex, movements of:, - the head, neck and trunk in response to visual and, auditory stimuli, and, - the eye muscles; changes in pupil size as well as, shape of the eye lens., (iii) Hind brain (Rhombencephalon): It consists of, three parts called cerebellum, pons and medulla, oblongata. Cerebellum lies at the roof of the hind, brain. This region controls the coordination of body, movements and posture. Pons lie just above the, medulla and take part in regulating respiration., Medulla oblongata lies at the floor of the hind brain, and continues into the spinal cord. It controls rate of, heart beat, breathing movements, expansion and, contraction of blood vessels to regulate blood, pressure, swallowing, coughing, sneezing and, vomiting., , Function of brain, The functions of brain are given below:, (i) The brain receives information carrying impulses, from all the sensory organs of the body., (ii) The brain responds to the impulses brought in by, sensory organs by sending its own instructions to the, muscles and glands causing them to function, accordingly., (iii) The brain correlates the various stimuli from, different sense organs and produces the most, appropriate and intelligent response., (iv) The brain coordinates the bodily activities so that, the mechanisms and chemical reactions of the body, work together efficiently., (v) The brain stores 'information' so that behaviour, can be modified according to the past experience., This function makes brain the organ of thought and, intelligence., Spinal cord, Spinal cord extends from the medulla oblongata, portion of the brain to the lumbar region, passing, through the neural canal of the vertebral column. It is, cylindrical in shape and from each segment of the, spinal cord, two spinal nerves arise. In man, 31 pairs, of spinal nerves are present. Each spinal nerve is a, mixed nerve and possesses both sensory and motor, fibres., , Table: Differences between cerebrum and cerebellum, , Cerebrum, , It is the part of hind, brain., It is much smaller,, constituting 12.5% of, the brain., It lies in the posterior, region of the brain., , Cerebellum, Functions of spinal cord, The functions of spinal cord are given below:, (i) Spinal cord is the main centre of reflex action., , 9

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(ii) It is concerned with the conduction of nerve, impulses to and from the brain., Autonomic nervous system (ANS), Peripheral nervous system (PNS), , Autonomic nervous system means 'self-governing, nervous system’. It operates automatically or, involuntarily. It includes all those responses against, stimuli which are not under the control of animal, involuntary activities). Visceral nerves of autonomic, nervous system control the activities of internal gans., Autonomic nervous system, therefore, is also termed, as visceral nervous system., The autonomic nervous system can be classified, anatomically and functionally into sympathetic and, parasympathetic nervous system. The smooth uscles, of various internal organs receive both sympathetic, and parasympathetic nerve fibres. Both the systems, have involuntary opposing effects. If one system, exerts stimulatory effect on an organ the other, system exerts inhibitory effect on that organ. Their, effects are tabulated in the given table., , Peripheral nervous system constitute the cranial and, spinal nerves along with their branches.,  Cranial nerves arise from the brain and spread, throughout the head. There are twelve pairs of, cranial nerves. Cranial nerves I, II and VIII are, sensory nerves; cranial nerves III, IV, VI, XI and, XII are motor nerves; and cranial nerves V, VII, IX, and X are mixed nerves (containing both sensory, and motor nerve fibres).,  Spinal nerves arise from the spinal cord along, most of its length and spread throughout the, body. There are 31 pairs of spinal nerves—eight, in the neck region, twelve in chest region, five in, abdominal region, five in hip region and one in, the coccyx region. Coccyx is the last bone of the, vertebral column. These are all mixed nerves as, they carry both sensory and motor nerve fibres., , Table: Effects of sympathetic system and parasympathetic system, Organ, Heart, Blood vessels, Lungs, Eyes, , Sympathetic system, Increases contraction and rate of heart beat., Constriction of blood vessels., Dilates bronchi and bronchioles., Dilates pupils., , 10, , Parasympathetic system, Decreases contraction and rate of heart beat., Dilation of blood vessels., Constricts bronchi and bronchioles., Constricts pupils.

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Stomach, Inhibits secretion of gastric juice in stomach. Stimulates secretion of gastric juice in stomach., Salivary glands Inhibits secretion of saliva in the bucal cavity. Stimulates secretion of saliva in the buccal cavity, Urinary bladder Relaxation., Contraction., Some important facts, , , , , , , , , , , , , , , , Brain is the highest coordination centre of human, body., Human brain is about 1200-1400 gm in weight, and has more than 100 billion (1010) neurons., Left half of brain controls right side of body and, vice versa., Lobes of human brain are hollow and their, cavities are called ventricles., Hypothalamus is commonly called thermostat of, body as it helps in regulation of body as it helps in, regulation of body temperature., Optic chiasma is cross of two optic nerves in front, of hypothalamus, Cavity of vertebral column in which spinal cord, lies, is called neural canal., Spinal cord acts as a link between brain and, peripheral nerve., Meningitis is inflammation of meningeal, membranes., Cerebellum is also called little brain, Brain stem is formed of mid brain, pons and, medulla oblongata., Vagus (x) cranial nerve is longest cranial nerve, and is the only cranial nerve which extends upto, abdomen., Near the sarcolemma, an axonal ending of motor, nerve fibre forms a flat motor end plate to, conduct the electrical impulses., Reflex arcs between the input nerve and the, output nerve are formed in the spinal cord,, although the spinal cord sends certain, information inputs to the brain through ascending, nerve fibres., , 9, Ans., , 10, , Ans., , 11, Ans.:, , 12, Ans.:, 13, Ans.:, , Synapse is the gap between nerve ending of, one neuron and dendrites of another. At, synapse, the electrical impulse generated at, dendrites of a neuron is passed on to dendrite, of another neuron in the form of chemicals by, axon ending of the first neuron. Synapse, ensures that nerve impulse travels only in one, direction. A Similar synapse allows the, delivery of impulse from the neuron to the, other cells, like muscle cells., Which part of the brain maintains posture and, equilibrium of the body?, Cerebellum, which is a part of the hind brain, maintains posture and equilibrium of the, body., How do we detect the smell of an agarbatti, (incense stick)?, Smell of and incense stick is detected by the, olfactory receptors located in the fore brain., What is the role of the brain in reflex action?, Nerves from all over the body meet in a, bundle in the spinal cord on their way to the, brain. Reflex arcs are formed in this spinal, cord itself, although the information input, also goes on to reach the brain, CHEMICAL COORDINATION IN ANIMALS, , In animals, the message, communicated in the form of, nerve impulses, from receptors (sensory neurons) to, central nervous system and from latter to the, effectors (muscles and glands) is very quick. The, nervous coordination in animals, however, has certain, limitations. For instance, - Nerve impulses can reach, only those animal cells which are connected by, nervous tissue, and - Such cells, after generation and, transmission of nerve impulses, take some time to, reset their mechanisms before a new impulse is, generated and transmitted., In other words, cells cannot continuously generate, and transmit electrical impulses. This is the reason, why most multicellular organisms use another means, of communication between cells, commonly termed, chemical communication. The stimulated cells release, a chemical directly into the blood. Other body tissue, cells have the means to detect this chemical using, special molecules (receptors) present either on their, surfaces or inside their cytoplasm. The message is, then transmitted and these chemicals produce their, effects., Chemical communication is, however, slow but it can, potentially reach all the cells of the body regardless of, , What is the difference between a reflex action, and walking?, Reflex action takes place without thought, i.e.,, it gives a reaction to stimuli. It is controlled, of one neuron and dendrites of another. At, synapse, by the spinal cord. It is an, involuntary action, Walking takes place after, thought, i.e., according to our wishes. It is, controlled by a part of hind brain called, cerebellum. It is a voluntary action,, What happens at the synapse between two, neurons?, , 11

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nervous connections. These chemicals are called, hormones and are secreted by various endocrine, glands. The latter constitute endocrine system., Hormonal information, like nervous system, is meant, for internal communication and regulation of animal, body functions. However, there are some basic, differences between the two controlling systems. Still,, the two systems (nervous system and endocrine, system) operate in a coordinated way on many, occasions. Many important functions of the endocrine, system are, in fact, under the control of nervous, system. Therefore, the two systems are often, collectively termed as neuroendocrine system., , fact, pancreas, ovaries and testes are both exocrine as, well as endocrine glands., The hormones in animals show following, characteristic feates:, , Table: Differences between nervous and hormonal information, , Nervous information, , 1. It is sent as an, electrical, impulse, along axons, and as a, chemical, across, 2. synapse., Information, ravels, 3. rapidly,, in, milliseconds., Information is directed, to specific receptors one or a few nerve, fibres, gland cells or, other neurons, i.e., it is, 4. addressed by name., , Hormonal information, , It is sent as a chemical, messenger via blood, stream., , Information, travels, slowly., Information is spread, throughout the body by, blood from which the, target cells or organs, pick it up, i.e., it is, addressed to 'whom it, may concern'., It gets response usually, slowly., 5. It, gets, response Its effects are generally, immediately., more prolonged., Its effects are shortlived., , (i) They are synthesized by endocrine glands., (ii) They are produced at a place other than the site of, action. They travel through blood to other parts, where they cause changes., (iii) They are secreted directly into the blood stream., (iv) They act on specific tissues or organs. The tissues, or organs that respond to the hormones are called as, target organs., (v) They are secreted in response to changes in the, external or the internal environment of the body and, are also called as chemical messengers, (vi) They may stimulate or inhibit the activity of the, target organ, thus regulating its activity., (vii) They are effective in minute quantities, often in, trace amounts which are difficult to detect at times., (vii) They are effective in minute quantities, often in, trace amounts which are difficult to detect at times., (viii) Excess or deficiency of a hormone may lead to, serious consequences., , Just as in plants, certain hormones control the life, activities in animals. These hormones are produced in, special organs called endocrine glands. Endocrine, glands are also called ductless glands as they have no, ducts and their secretions are poured directly into the, blood. Endocrine glands though present in different, regions of the body, work in coordination as an, integrated system. A variety of chemical substances/, called hormones, are secreted in trace amounts by, endocrine glands., Hormones, therefore, are chemical substances, secreted in trace amounts by endocrine glands and, are the means of information transmission., In animals, in. addition to ductless endocrine glands,, some glands with ducts are also present. These, glands, like the pancrease, ovaries and testis, have, ducts and are called exocrine glands. As a matter of, , Human endocrine glands, The major endocrine glands, their secretions, principal, functions of the various hormones secreted by them, are listed in the given table., , Table: Major hormones secreted in the human body, their sources and principal function, , 12

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Endocrine glands and their locations, , HEAD REGION, 1. Hypothalamus, 2. Pituitary gland, • It has three lobes. It is attached, to the lower surface of the, brain., (i) Anterior lobe, • It produces six hormones., , ., , (ii) Intermediate lobe, (iii)Posterior lobe, , 3. Pineal gland, • It lies between the two, cerebral hemispheres of the, brain., NECK & CHEST REGION, 4. Thyroid gland, • It is situated in the neck region, on the ventral side of the body., It has two lateral lobes one on, either side of the trachea., 5. Parathyroid gland, • These are four small oval, bodies which lie embedded in, the lobes of the thyroid gland., , Hormones secreted, , Principal functions, , Thyrotrophin-releasing hormone, (T-RH), , (a) Growth hormone (GH) or Controls the overall development or, Somatotrophic hormone (STH), growth of the body, muscles, bones and, tissues. Lack of this hormone (hypoactivity), causes dwarfness. Its excessive secretion, (hyperactivity) causes excessive growth of, bones making the person very tall, (gigantism)., (b) Thyroid stimulating hormone Controls the growth and functioning of the, (TSH), thyroid gland. Stimulates the thyroid gland, to produce thyroxine., (c) Adrenocorticotrophic, Stimulates the adrenal cortex to secrete its, hormone (ACTH), hormones., (d) Follicle stimulating hormone In males, it stimulates the process of, (FSH), spermatogenesis (sperm formation). In, females, it stimulates the follicle cells in the, ovaries to develop into mature eggs and, also stimulates them to produce oestrogen., (e) Luteinising hormone (LH) (FSH In males, it stimulates the secretion of male, and LH are together called hormone, testosterone (sex hormone in, gonadotropins’), males). In females, it stimulates the, secretion of oestrogen and progesterone, (sex hormones in females)., (f) Prolactin hormone (PRL), Enhances mammary gland development and, milk production in females., Melanocyte stimulating hormone Stimulates the synthesis of melanin in the, (MSH), skin., (a) Oxytocin, Stimulates contraction of smooth muscles at, the time of child birth. It also helps in milk, ejection (lactation) from the mammary, glands., (b) Vasopressin or Antidiuretic Regulates water and electrolyte balance in, hormone (ADH), body fluids., Melatoni, Regulates the working of gonads, , T4 T3 & T4 stimulates the rate of cellular, (a) Thyroxine or T4 of, oxidation and metabolism., (b) Triiodothyro- of nine or T3, Calcitonin lowers calcium level when by, (c)Calcitonin., suppressing release of calcium ions from the, Parathyroid hormone (PTH) or bones, calcium level is high in blood., parathormone., Regulates calcium and phosphate levels in, the blood. When blood calcium level is, below normal, it mobilizes the release of, calcium into the blood from bones. It has an, , 13

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action opposite to that of calcitonin on, calcium metabolism., Stimulates, the, development, and, differentiation of lymphocytes (white blood, cells)., , 6. Thymus gland, Thymosin, • It is situated in the upper chest, near the front side of the heart., • It atrophies in the adult., ABDOMINAL REGION, 7. Adrenal gland, • In human beings, a pair of, adrenal glands are present, one, on top of each kidney, so, also, called, suprarenals., Each, adrenal gland has an outer part, called the cortex and an innerpart, medulla., (i) Adrenal cortex, (a) Glucocorticoids, • It secretes 3 groups of steroid, hormones., , Regulates the metabolism of protein, fats, and carbohydrates in the body and the level, of blood sugar. Regulates heart rate and, blood pressure., (b), Mineralocorti, coids Regulates water and mineral balance in, (Aldosterone), body., (c) Sex corticoids, Stimulates the development of secondary, sexual characters both in males and, females., (ii)Adrenal medulla A, Adrenaline, Epinephrine) and Both these hormones together control, • It secretes 2 hormones., Nor-adrenaline, emotions, ear, anger, blood pressure, heart, ( Nor-epinephrine), beat, espiration and relaxation of smooth, muscles., Regulates the coversion of glucose to, glycogen; e., it lowers blood glucose level., 8. Pancreas, (a) Insulin, Regulates the conversion of glucose to, It is a compound gland in the, glycogent; i.e., it lowers blood glucose level., abdominal region located posterior (b) Glucagon g, Regulates the conversion of glycogen back, to the stomach. Its (b endocrine, to glucose i.e., it increases blood glucose, part is Islets of Langerhans, which, level., secretes 2 hormones, 9. Ovaries, • These are a pair of organs Progesterone and Oestrogen, Plays an important role in ovulation. These, present in the lower abdominal, help in the preparation of uterus for the, region in females., reception of fertilized ovum., These hormones also help in the, maintenance of pregnancy., Oestrogens are responsible for development, of secondary sexual characteristics in, females like mammary gland, voice, hair, 10. Testes, pattern, etc., • These are extra- abdominal in Testosterone, Regulates the growth, development and, position., functioning of accessory sex organs and, • The interstitial or Leydig cells, controls the secondary sexual characteristics, present in testes produce the, in males, such as enlargement of penis and, male hormone., scrotum, growth of facial and pubic hair,, and enlargement of larynx that causes, deepening of voice., , 14

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Table: Summary of hypothalamic hormones and pituitary response, Hypothalamic hormones, 1. Thyrotrophin-releasing hormone (T-RH), 2. Andrenocorticotrophin- releasing hormone, (A-RH), 3. Follicle stimulating hormone- releasing, hormone (FSH-RH), 4. Luteinising hormone- releasing hormone, (LH-RH), 5. Growth hormone-releasing hormone (GHRH), 6. Growth hormone releaseinhibiting, hormone (GH- RIH) or somatostatin, 7. Prolactin-releasing hormone, (P-RH), 8. Prolactin release-inhibiting hormone (P-RIH), , Response of pituitary Thyroid, Target organ, stimulating hormone (TSH) secretion, Thyroid, Adrenocorticotrophic hormone, Adrenal cortex, (ACTH) secretion, Follicle stimulating hormone (FSH) secretion Ovary/Testis, Luteinising hormone (LH) secretion, , Ovary/Testis, , Growth hormone (GH) or somatotrophic Most tissues, hormone (STH) secretion, Growth hormone secretion inhibited, –, Prolactin hormone (PH) or luteotrophic Mammary glands, hormone (LTH) secretion, Prolactin secretion inhibited, –, , DISORDERS OF ENDOCRINE GLAND, , common salt is iodised to provide required iodine to, the thyroid gland., (iii) Myxoedema: It is caused by deficiency of thyroid, hormones in adults. It is more common in women, than in men., (iv) Cretinism: Hypothyroidism (hypoactivity of, thyroid gland) causes cretinism in young children. Its, symptoms are stunted growth, short club-like fingers,, deformed bones and teeth. Skin is rough, dry and, wrinkled with scanty hair growth. Pot-bellied, abdomen. Idiocy of varying degree is observed., , Disorders of pituitary, (i) Dwarfism: Dwarfism is caused due to deficiency of, growth hormone from early age., (ii) Gigantism: It is giant size of the youngs with very, tall skeleton and proportionally large muscles and, viscera. It is caused due to excess secretion of growth, hormone from childhood., (iii) Acromegaly: It is caused due to excess secretion, of growth hormone after adolescence. Acromegaly in, adults leads to overgrowth of the jaw bones and, bowing of me spine (backbone)., (iv) Diabetes insipidus: Deficiency of ADH reduces, reabsorption of water and increases urine output/, causing excessive thirst. This disorder is called, diabetes insipidus. No glucose is lost in the urine of, such a patient., , Deficiency of insulin, Diabetes mellitus: Deficiency of insulin hormone in, the body causes a disease known as diabetes mellitus., In this disease, the patient excretes sugar (glucose) in, urine, feels excessive thirst and also does excessive, urination., , Improper secretion of thyroid hormones, (i) Grave's disease (exophthalmic goitre): It is caused, by hyper secretion (over secretion) of thyroid, hormones due to enlargement of thyroid gland., Excess of thyroid hormones increases metabolic rate, and accelerates oxidation. This results in quick, consumption of food, leaving nothing for storage and, causing emaciation (excessive leanness)., (ii) Simple goitre (iodine deficiency goitre or endemic, goitre): It is the enlargement of thyroid gland, accompanied with cretinism or myxoedema. It is, caused due to dietary deficiency of iodine. The, disease is common in hilly areas. It causes, enlargement of thyroid gland. Swollen neck is one of, the symptoms of this disorder. Addition of iodides to, the table salt prevents the disorder. In our country,, , 14., Ans., , 15, , How does chemical coordination take place in, animals?, In animals, chemical coordination is, maintained by hormones secreted by, endocrine glands, which function as chemical, messengers. They are released by endocrine, glands directly into the blood without any, involvement of special ducts from where they, reach the target tissue or organ to act. These, organs and tissues then responses and, enables the body to deal with different, situation.

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15., Ans., , 16., Ans., , Why is the use of iodized salt advisable?, Iodine is necessary for the thyroid gland to, make thyroxine hormone. Thyroxine regulates, carbohydrates, protein, and fat metabolism in, the body so as to provide the best balance for, growth. If iodine is deficient in our diet, there, is a possibility that we might suffer from, goiter. The thyroid gland enlarges causing, swelling in the neck. Iodized common salt, contains proper content of iodine. Thus, to, avoid deficiency of iodine, iodized salt is, recommended., How does our body respond when adrenaline, is secreted into the blood?, Adrenaline hormone is secreted in large, amounts when a person is frightened, or, mentally disturbed. When it reaches the, , 17., Ans., , 16, , heart, it beats faster to supply more oxygen to, our muscles. The breathing rate also increases, because of the contraction of diaphragm and, the rib muscles. It also raises the blood, pressure, and allows more glucose to enter, into the blood. All these responses together, enable our body to deal with the emergency, situations., Why are some patients of diabetes treated by, giving injections of insulin?, Diabetes is caused due to less or no secretion, of hormone inulin by pancreas. In such a, person, blood sugar level is high. Insulin, converts extra sugar present in blood into, glycogen. Thus, patients suffering from, diabetes are given insulin injection to control, their blood sugar level.

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, , , , , PHOTOPERIODISM, , , , , , , The duration of sunlight regulates the, germination of seeds and flowering in plants. The, length of the day (in hours) during which the, sunlight is available to the plants is called, photopenod the effect of photopenod on the, germination of seeds and flowering in plants is, called photoperiodism., Photoperiod acts as a stimulus for plants. The, plants respond to this stimulus with the help of a, special kind of pigment present in them in very, small amounts. This special pigment is called, phytochrome which is a blue-green pigment., Seeds of many plants germinate only if they are, exposed to particular day length of light showing, involvement of phytochrome pigment, e.g., seeds, of lettuce., Photopenod exerts significant effect in the, flowering of plants. Gamer and Allard (1920), recognized three classes of plants according to, their photoperiodic responses :, (i) Short day plants (SDP): Such plants need, longer dark periods for flowering, e.g., tobacco,, rice, dahlia, soyabean tec., (ii) Long day plants (LDF): Such plants need, shorter dark periods for flowering, e.g., wheat,, oat, radish, tettuce etc., (iii) Long day plants (LDP): Such plants are not, dependent on photopenod for flowering, e.g.,, tomato sunflower etc., , ABSCISSION, , , , , , , , , , , , , , , , , There are plants for which flowering is either, quantitatively or qualitatively dependent on, exposure to low temperature. This phenomenon, is termed vernalisation. It prevents precocious, reproductive development late in the growing, season, and enables the plant to have sufficient, time to reach maturity., Site of vernalisation is apical meristematic cells,, e.g., shoot tip, embryo tips, root apex, etc, As a result of vernalisation, a flowering hormone, called vemalin is formed (reported by Melchers),, but vemalin has never been isolated., , Seeds of some plants like rice/ maize, germinate, immediately after reaching the ground Seed of, Citrus and Rhizophora germinate "in situ". This is, called vivipary., But in majority of plants seeds remain in an, inactive state and germinate only after a specific, period of rest. Such inactive state is called, dormancy or quiescence, Dormancy may be denned as, "the inactive state, of the seed in which growth of the embryo is, temporarily suspended for a specific length of, time"., After the onset of specific conditions, seed, dormancy is broken. Dormancy of seed can break, naturally or it can be induced artificially., PHYTOHORMONES, , , , •, , , •, , , Importance of vernalisation, , , It is a natural shedding of leaves, fruits or flowers, from the plants without any response to injury, but due to change in hormonal balance., A special narrow zone called abscission zone, develops in the area of future abscission It may, have a shallow growth or different colour. Both, xylem and phloem get blocked initially by tyioses, and callose respectively., It produces degenerative changes, phloem plugs, soon dissolve and various nutrients present in, abscising organ pass back into the plant., SEED DORMANCY, , VERNALISATION, , , Plants can be grown in such regions where, normally they do not grow., Yield of the plant is increased., Resistant to cold and frost is increased., Resistance to fungal diseases is increased., , •, , Crops can be grown earlier. Juvenile or vegetative, period is shortened and brings about early, flowering., , , , 19, , Gibberellin was first reported from the fungus, Gibberella fujikuroi which causes bakanae disease, (foolish seedling) in rice., Most commonly found gibberellin is gibberellic, acid-3 (GA3 )., First natural cytokinin reported was zeitin. Natural, cytokinins are also found in coconut water and, apple fruit extract., Kinetin is a synthetic cytokinin., Climacteric fruits release ethylene phytohormone, during their ripening, e.g., apple, banana etc, Abscisic acid (ABA) is also called dormin and tress, hormone., Morphactins are a group of artificially synthesized, substances which affect morphology and hence, called morphactms. These contain "fluorene ring"

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, , , , in their structure. Generally these are growth, inhibitors., Haberlandt (1913) reported that injured plant, cells release a chemical substance (wound, hormone), which stimulate the adjacent cells to, divide rapidly in order to heal up the wound, English et. al (1939) finally isolated and, crystallized this wound hormone and named it as, traumatic acid., FIorigen is unidentified hypothetical flowering, hormone thought to be present in photo induced, leaves of plants. This hormone neither has been, isolated not its chemical nature has been, determined., , , , , •, , •, , NERVOUS COORDINATION IN LOWER ORGANISMS, , , , , , , , , meninges (singular meninx) between the brain or, spinal cord and their respective bony cases., There are 3 meninges in humans - piamater,, arachnoid and duramater., Duramater is the outermost double layered thick, and tough, non-vascular meninx. It lines the, cranial cavity., Arachnoid is thin, webby and slightly vascular, middle sheath. There is a space between, duramater and arachnoid named as subdural, space that is filled with fluid (not cerebrospinal, fluid)., Piamater is the inner one and thinnest of all, meninges. It is vascular and pigmented sheath, that lies in contact with brain., CEREBROSPINAL FLUID, , In coelenterates (e.g., Hydra), diffused nervous, system is present. It is formed of epidermal nerve, net and gastro dermal nerve net of nerve cells, present on outer and inner border of a gelatinous, layer, called mesoglea., In flatworms (e.g., Planaria, liver fluke, tape, worm, etc.), nervous system is of ladder type It is, formed of a ganglionated nerve ring (a ganglion is, a mass of neurons) and the nerve cords. The latter, are interconnected by a number of transverse, connectives., Annelids (e.g., earthworm) were the first animals, to have a well-organized centralized nervous, system. This comprises a circum-phaiyngeal nerve, ring and a nerve cord. Nerve ring is formed of a, bilobed brain dorsal to pharynx and a bilobed, subphaiyngeal ganglia ventral to pharynx which, are interconnected by a pair of circum pharyngeal, connectives. Nerve cord is ventral single, ganglionated and lies below the alimentary canal., Each ganglion gives nerves to different parts of, the body, In insects (e.g., cockroach, grasshopper, etc.), central nervous system is similar to that of, annelids except:, - Nerve ring is circum-oesophageal (i.e., around, the oesophagus)., - Nerve cords are ventral solid, ganglionated, but double. Two nerve cords remain separate, except at the ganglia., , , , , , , Cerebrospinal fluid is a clear, colourless, slightly, alkaline fluid present in the ventricles of the brain,, central canal of spinal cord and spaces between, the meninges. It protects the CNS from shocks, and keeps it moist., It also carries harmful metabolic wastes, drugs, and other substances from the brain to the blood., CSF also maintains a constant pressure inside the, cranium inspite of variation in the pressure of, blood in the cranial vessels., ELECTROENCEPHALOGRAPH, , , , Electroencephalograph is an instrument which, records the electrical activity of the brain in the, form of a graph of electric potentials generated, with time. Such a record is called, electroencephalogram, (EEG)., The, electroencephalogram (EEG) of a patient is done, by, placing, two, electrodes, of, electroencephalograph instrument on the scalp of, the patient. Then, a record of four different types, of waves (alpha, beta, delta and theta) is, produced on the graph paper. These waves vary, in their frequency. These waves give the, characteristic activity of the brain of a person. The, EEG of a patient is useful to diagnose brain, ailments., DISORDERS OF NERVOUS SYSTEM, , PROTECTIVE COVERINGS, , , •, , Both brain and spinal cord are protected from, mechanical injury and shock by bony cases around, them. Brain is protected by cranium while spinal, cord is protected by vertebral column. There are, also present additional protective coverings called, , •, , 20, , Poliomyelitis: Poliomyelitis is an acute viral, infection that destroys the cell bodies of motor, neurons in the anterior horn of the spinal cord., Meningitis: Meningitis, an inflammation of the, meninges, is usually caused by an infectious, organism. Several kinds of bacteria and viruses, can infect the meninges.

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•, •, , , , , •, , , , , Neuritis: Neuritis is a general term for, disturbances of the peripheral nervous system., Multiple sclerosis: Multiple sclerosis is a, progressive degenerative disease of central, nervous system., ', Sciatica: It is an irritation or neuritis of the sciatic, nerve. In fact it is pain along the sciatic nerve., Neuralgia: Neuralgia is pain in a circumscribed, area innervated by a sensory nerve of the, peripheral nervous system., Parkinson's disease: It is caused by the, destruction of the neurons of basal ganglia that, produce the neurotransmitter dopamine. Thus, dopamine is reduced in the brain. Symptoms, include tremors and shakes in the limbs, a slowing, of voluntary movements and feeling of, depression., Wilson's disease: Along with all symptoms of, Parkinson's disease, there is degeneration of liver, tissues also., Alzheimer's disease (AD): It is caused due to, destruction of vast numbers of neurons in the, hippocampus (a part of brain). Evidence suggests, that it is due to a combination of genetic factors,, environmental or lifestyle factors and the ageing, process., - There, is, loss, of, neurotransmitter, acetylcholine., - Individuals with AD initially have trouble, remembering recent events. In the later, stages, the patients may fail to recognize their, spouse or children., Schizophrenia: It is a severe mental illness, characterized by a disintegration of the process of, thinking, of contact with reality, and of emotional, responsiveness. Positive symptoms, such as, delusions and hallucinations (especially of voices),, are common., , , , , , HOMEOSTASIS AND FEED BACK, , , Homeostasis means keeping the internal chemical, environment of the body constant. Hormones, help to maintain homeostasis by their integrated, action and feedback control. Feedback control is, mostly negative, and rarely positive., Negative feedback control, , , , TYPES OF GLANDS, , , (iii) Heterocrine glands consist of both exocrine, tissue and endocrine tissue. The exocrine tissue, sends its secretion or product by way of a duct;, the endocrine tissue discharges its secretion into, the blood. Pancreas and gonads (testes and, ovaries) are examples of heterocrine glands. The, endocrine portion of pancreas secretes insulin, and glucagon hormones. On the other hand, the, exocrine portion secretes pancreatic juice, containing digestive enzymes (trypsin, lipase and, amylase) into the pancreatic duct that leads to the, alimentary canal., Similarly, endocrine portion of the testis (male, gonad) secretes testosterone hormone while the, exocrine part releases sperms (male gametes) into, the duct., Ovaries (female gonad) too have endocrine as, well as exocrine tissues; the former secretes, estrogen and progesterone hormones, and the, latter release ova (female gametes) into the duct., , Animals have three types of glands as following :, (i) Exocrine glands have ducts for discharging, their secretions on to the body surface or into the, cavities in the body. Sweat and sebaceous glands, in the skin, salivary glands around the buccal, cavity, gastric glands in the stomach wall, and liver, are some examples of exocrine glands., (ii) Endocrine glands lack ducts and pass their, secretions into the surrounding blood for, transport to the site of action. They are also called, ductless glands. Pituitary, thyroid, parathyroid, glands, adrenal glands etc. are examples of, endocrine glands., , In a negative feedback control, synthesis of a, hormone slows or halts when its level in the blood, rises above normal. The given example of bloodglucose homeostasis is cited to explain the, negative feedback control., Blood-glucose homeostasis: When we eat a, Carbohydrate-rich meal blood sugar level is, increased. It stimulates pancreas gland to secrete, insulin. The latter stimulates the target cells to, take up extra glucose which is either utilized in, cell respiration or is stored as glycogen. In this, way, blood-glucose level is brought back to, normal, , Positive feedback control, 21

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, , , , , In the positive feedback control, an accumulating, biochemical substance increase its own, production., For example, at the onset of labour pain in female, before child birth, uterine contraction stimulates, the release of oxytocin hormone from posterior, lobe of pituitary gland. The latter intensifies, uterine contractions. The contractions further, stimulate the production of oxytocin. The cycle of, increase stops suddenly after birth of the baby., , , , , , MODE OF ACTION OF HORMONES, , , , , , , , , , CELLS OF PANCREAS, , , The secretion of hormone from an endocrine, gland is controlled by its circulating level in the, blood., Action of hormones are carried via the blood, throughout the entire body, yet they affect only, certain cells., The specific cells that respond to a given hormone, have receptor sites for that hormone. This is a, sort of lock and key mechanism., If a hormone fits the receptor site, then there will, be an effect. All the cells that have receptor sites, for a given hormone make up the target tissue for, that hormone., In some cases, the target tissue is localized in a, single, gland or organ. In other cases, the target, tissue is diffused and scattered throughout the, body so that many areas are affected. Hormones, bring about their characteristic effects on target, cells by modifying cellular activities., Hormones can be classified by the location of the, receptor and by the nature of the signal or second, messenger used to mediate hormone action, within the cell., , , , , , , , , , Pancreas has groups of cells called islets of, Langerhans. These produce endocrine secretions., Four kinds of cells have been identified in the, islets., (i) Alpha cells (about 15 %) produce glucagon., (ii) Beta cells (about 65 %) produce insulin., (iii)Delta cells or D-cells (about 5 %) produce, somatostatin (SS)., (iv) Pancreatic polypeptide cells or PP cells or F, cells (15 %), produce pancreatic polypeptide (PP)., Somatostatin seems to suppress the release of, hormones from the pancreas and digestive tract., Pancreatic polypeptide inhibits the release of, digestive secretion of the pancreas., HORMONES OF THYROID, , , , , , HORMONES OF KIDNEYS, , , The oxygen shortage stimulates the kidney cells to, secrete a hormone named erythropoietin (a, circulating glycoprotein) into the blood., Erythropoietin stimulates the bone marrow to, increase the production of RBCs., Vitamin D exists in two forms: calciferol or D2 and, cholecalciferol or D3, Calcitriol is the active form of vitamin, cholecalciferol (D3). It promotes absorption of Ca2+, and phosphorus in the small intestine and, accelerates bone formation., , , , The kidneys secrete three hormones: renin,, erythropoietin and calcitriol., Whenever the rate of ultrafiltration falls, the cells, of their juxtaglomerular complex secrete and, release into blood a compound named renin. It, acts upon a plasma-protein, angiotensinogen,, separating a compound, called angiotensin-II from, it., Angiotensin-II accelerates heart beat and, constricts arterioles, thereby increasing blood, pressure. This enhances the rate of ultrafiltration., Simultaneously, the angiotensin-II stimulates, adrenal cortex to secrete aldosterone and, enhances water and sodium reabsorption from, nephrons. These factors also elevate blood, pressure., , Thyroid hormones are produced by the secretory, cells lining the follicle and stored in the colloid, (homogenous materials in follicles) until needed., So each follicle accumulates a storage form of the, circulating thyroid hormones - thyroglobulin., Thyroglobulin is a large protein molecule that, contains multiple copies of one amino acid, tyrosine., Thyroid gland produces two hormones - thyroxine, (T4) and tri-iodothyronine (T3) together called, (homogenous material in follicles) thyroidal, hormone. Both are iodinated forms of an amino, acid called tyrosine. T3 and T4 contain 3 and 4, iodine atoms respectively. T3 is more potent and, active than T4, GLANDS OF EMERGENCY, , , , , 22, , The medulla of the adrenal glands secretes two, hormones: nor-epinephrine (noradrenaline) and, epinephrine (adrenaline)., Nor-epinephrine (Nor-adrenaline) regulates the, blood pressure under normal condition. It causes, constriction of essentially all the blood vessels of, the body. It causes increased activity; of the heart,

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, , , , , inhibition of gastrointestmal tract, dilation of the, pupils of the eyes and so forth., Epinephrine (Adrenaline) is secreted at the time, of emergency. Hence it is also called emergency, hormone. It causes almost the same effects as, those caused by nor-epinephrine, but the effects;, differ in the following respects., - First, epinephrine has a greater effect on, cardiac activity than norepinephrine., - Second, epinephrine causes only weak, constriction of the blood vessels of the, muscles., - A third difference is that epinephrine, probably has several times as great metabolic, effect as nor-epinephrine., Because of the role of their hormones, the, adrenal glands are also called 'glands of, emergency’., The above role of adrenaline and nor-adrenaline, is often called "fight or flight reaction". It prepares, the body to face stress or danger., , 1., , Ans., 2., , Ans., 3., , Ans., 4., Ans., 5., Ans., 6., Ans., , 7., , Ans., , 8., , Ans., , 9., Ans., , 10., Ans., , Name the element of halogen family which is, required for the proper functioning of thyroid, gland., Iodine., A doctor advised a patient to take less sugar, in her diet. Which disease is she suffering, from?, Diabetes, due to deficiency of insulin., A patient is not able to balance his body and, cannot walk properly by keeping the balance, and cannot coordinate it. Name the part of, brain which is affected., Hind brain., What are the limitations of electrical impulse?, It reaches only to target organs and it cannot, recreate the signal again., If there is no neuron in an organ, how will the, message reach in other way?, The message can be sent by hormones if the, nervous system or nerves lack., How does chemical coordination take place in, plants?, Unlike animals, plants do not possess nervous, system and rely entirely on chemical, coordination. Their, responses, are, therefore slower and often involve growth., Since in plants, chemicals have their effects, on, some aspect of growth, they are, called growth substances., What is a stimulus?, , 11., , Ans., , 12., Ans., 13., Ans., , 23, , A stimulus may be an external or internal, factor which initiates a response in a living, organism due to its, property, of, irritability., Give the technical names for the following, receptors in the animals:, (a) Receptors for light, (b) Receptors for temperature, (c) Receptors for sound, (d) Receptors for smell., (a) Photoreceptors, (b) Thermoreceptors., (c) Phonoreceptors, (d) Olfactoreceptors., What do you mean by CSF? Give its function., CSF or cerebrospinal fluid is a lymph-like fluid, found between the meninges around the, brain and spinal cord. It protects them from, mechanical shocks and keeps it moist., What is the significance of reflex actions?, Reflex action has following significances:, (i) These enable the body to give quick, responses to harmful stimuli. It decreases the, chances, of damage, caused to the body., (ii) These are controlled by spinal cord so, prevent overloading and fatigue of brain., Which hormone is released into blood when, its sugar level rises? Name the organ which, produces the hormones and its effect on, blood sugar level., (i) Insulin hormone is released into blood, when sugar level in blood rises. Insulin, hormone is produced by Pcells, of, endocrine part of pancreas. It converts excess, of sugar - (glucose) into glycogen., Name the hormones secreted by kidneys., The kidneys secrete three hormones: renin,, erythropoietin and calcitriol, What does the given diagram demonstrate?, In this diagram, a pot is lying horizontally. The, shoot is growing upward and the root is, growing, downward., The, diagram, demonstrates, the, phenomenon, of, geotropism. The shoot is moving away from, gravity exhibiting negative geotropism while, the root is growing towards gravity, exhibiting, positive geotropism.

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18., Ans., 14., Ans., , 15., , Ans., , 16., Ans., , 17., Ans., , Why is pancreas called heterocrine gland?, Ductless glands are called endocrine glands, and glands with ducts are called exocrine, glands. Pancreas functions both as endocrine, gland as well as exocrine gland. Its endocrine, parts are the islets of Langerhans from which, important hormones like insulin and glucagon, are produced. Its exocrine parts are the acini, from where digestive enzymes are secreted, Hence, pancreas is heteroclite because of its, dual function as endocrine as well as exocrine, glands., A person has developed goitre in his neck., How would you identify whether it is endea, goitre or exopthalmic goitre?, Endemic goitre occurs due to hypo secretion, of thyroxine while exopthalmic goiter caused, by hyper secretion of thyroxine. If a person, has goitre, symptoms is observed to ascertain, the nature of goitre. Along with goitre, if the, patient has low blood pressure, low sugar, level slow heart beat rate, low body, temperature, loss of appetite, tendency, towards obesity. sluggishness, etc. then he is, having endemic goitre. On the contrary, if, along with goitre the person has high blood, pressure,, high, body, temperature, hyperghicemia, faster heartbeat, increased, appetite, palpitation, restlessness and bulging, eye balls (exophthalmus), then he is having, exophthalmic goitre., What do you mean by short day plant and, long day plants?, Short day plants and long day plants are, categorized according to their photoperiod, responses. Short day plants (SDP) need, longer dark periods for flowering, e.g.,, tobacco, rid dahlia, soyabean, etc. Long day, plants (LDP) need shorter dark periods for, flowering, e. j wheat, oat, radish, lettuce, etc., What causes instant death by hanging?, Brain stem or medulla oblongata is the most, vital part of the brain containing d control, centre for respiration, heartbeat, reflex, action, vasomotor dilation, etc. When, prisoner is hanged, the noose cord breaks the, , 19., Ans., , 20., , Ans., , 1., , Ans., 2., , Ans., 3., 24, , atlas (first vertebra); as a result, the point, odontoid process of the axis (second, vertebra) pierces the brain stem, leading to, instant death., Which plant hormone delays abscission of, leaves and fruits?, Auxin delays abscission of leaves and fruits. It, prevents the formation of abscissia zone, below a leaf or fruit., Abscission zone cuts, off nutrients and water supply resulting fall of, leaves and fruits. Nonformation of abscission, zone due to auxin delays the abscissia of, leaves and fruits., A dog has a better sense of smell as compared, to human beings. Give reasons., Olfactory receptor cells present in the nasal, epithelium function as chemoreceptors as, they are stimulated by specific chemical, substances present in odour. In human, beings, the olfactory receptor cells are, present only in a small area in the roof of the, nasal cavity near the nasal septum. But it is far, more extensive in animals like dogs. This is, the reason why dogs possess such an acute, olfactory sense. Many thousand types of, odours are discernible to dogs., Take a live frog. Insert your dissecting box pin, in between skull and first vertebra and, damage the connection between brain and, spinal cord (a process called pithing). Now,, dissect the frog. You will find that the frog,, though alive, will not move out of pain., Explain why it happens?, The centres for pain and movement are, situated in brain. The stimulus reaches brain, through spinal cord., When communication, between spinal cord and brain has been, disrupted, neither the stimulus of pain, reaches the brain nor the message from brain, reaches the limbs to move or to become, restless. So, the pain- free frog will not, move., , Which of the following is a plant hormone?, (a) insulin, (b) thyroxine, (c) oestrogen, (d) cytokinin, Cytokinin., The gap between two neurons is called a, (a) dendrite, (b) synapse, (c) axon, (d) impulse, Synapse., The brain is responsible for

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Ans., 4., , Ans., , 5., Ans.:, , (a) thinking, (b) regulating the heart beat, (c) balancing the body, (d) all of these., All of these., What is the function of receptors in our, body? Think of situations where receptors do, not work properly. What problems are likely, to arise?, The receptors in our body collect information, about changes in the environment around us, in the form of stimuli. They are located in our, sense organs such as the inner ear, nose,, tongue, eye, etc. These then pass the, information in the form of nerve impulses to, central nervous system (spinal cord and brain), where message is interpreted and instructions, are sent to effectors which reveal responses., When receptors do not work properly, the, environmental stimuli are not able to create, nerve impulses and body does not respond., Draw the structure of a neuron and explain, its function., Functions- The information acquired at the, end of the dendritic tip of a neuron sets off a, chemical reaction which creates an electrical, impulse. The impulse travels from the, dendrite along the axon of its end. At the end, of axon/ the electrical impulse sets off the, release of some chemicals, which cross the, synapse and start a similar impulse in a, dendrite of the next neuron., , 7., Ans., , 8., Ans., , 9., Ans., , 10., Ans., , 6., Ans., , In this way nerve impulses travel in the body., Thus, nervous tissue is made up of an, organized network of neurons which are, specialized for conducting information via, electrical impulse from one part of the body, to another., How does phototropism occur in plants?, Phototropism is a directional growth which, occurs in response to unidirectional exposure, to light. Phototropic movement is generally, caused by increased auxin on the dark side, and lesser auxin on the illuminated side. Due, to the presence of more auxin, the part of the, plant stem in the dark grows faster, causing it, to bend towards the source of light., 25, , Which signals will get disrupted in case of a, spinal cord injury?, The following signals will get disrupted in case, of a spinal cord injury:, - Reflex action, - Impulses from various body parts will not, be conducted to brain., - Message from brain will not be conducted, to various organs of the body., How does chemical coordination occur in, plants?, In plants, chemical coordination occurs by, plant hormones or phytohormones; Plant, hormones are chemical substances other than, nutrients, which are produced at specific, places in the plant (usually from tips of, shoots, roots and branches), and then are, diffused to a specific site without, translocation to other sites. Phytohormones, produce effects like cell multiplication,, growth, opening of flowers and regulate, physiological processes., What is the need for a system of control and, coordination in an organism?, The body of a multicellular organism consists, of a number of components and subcomponents and each is specialized to, perform a particular function. Therefore, it is, necessary that various organs of the body of, an organism work together in a proper, manner for proper functioning to a stimulus., In human beings nervous system and, endocrine system work together for control, and coordination., How are involuntary action and reflex action, different from each other?, Involuntary action, (i) Involuntary action involves autonomic, nervous system., (ii) They occur in response to internal stimuli,, (iii) They are connected with functioning of, internal body parts., (iv) It occurs without the will of the organism., For example, heartbeat, breathing, etc., (v) These are regulated by medulla oblongata, (hind brain)., Reflex action, (i) Reflex action involves all parts of voluntary, nervous system though they are not, voluntary,, (ii) They operate against harmful stimuli which, are generally external., (iii) They are connected with emergency i.e.,, response to stimuli.

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(iv) Some reflexes involve the brain, rather, than the spinal cord., (v) Reflex is generally controlled by spinal, cord., Name the organism which lacks nervous, system., Plants lack nervous system., What is the difference between the manner, in which movement takes place in a sensitive, plant and the movement in our legs?, The differences between movement in a, sensitive plant and the movement in our legs, are given below:, , 11., Ans., 12., , Ans., , 1., , 2., , 3., , Movement in a sensitive plant, , Movement in legs, , It occurs in response to, an external stimulus like, touch,, pressure, or, shock., It is brought about by, turgor, changes, in, specific cells., It is controlled by plant, hormones., , It occurs voluntarily in, response to our need, and will., , 13., , Ans., , 2., , It is brought about by, contraction, and, relaxation of muscles., It is controlled by, cerebellum of the hind, brain., , Ans., , Compare and contract nervous and, hormonal mechanisms for control and, coordination in animals., , Ans., 1., 2., , 3., 4., 5., , Nervous System, , Endocrine System, (Hormonal System), , Made of neurons or, nerve cells., Massages transferred, in the form of electrical, impulses., Messages transferred, along the nerve fibres., Messages travel very, quickly., Effect of message, usually last for a very, short time., , Made of secretory cells, and glands., Messages transferred in, the form of chemicals, called hormones., Messages, transmitted, through blood system., Messages travel slowly., , 3., , Effect of message usually, lasts longer., , Ans., , 4., , Multiple Choice Questions (MCQs), 1., , Ans., , Which of the following statements -is correct, about receptors?, (a) Gustatory receptors detect taste while, olfactory receptors detect smelt, (b) Both gustatory and olfactory receptors, detect smell, , 5., , 26, , (c) Auditory receptors detect smell and, olfactory receptors detect taste, (d) Olfactory receptors detect taste and, gustatory receptors smell, (a) A receptor is a cell (or a group of cells) in a, sense organ which is sensitive to a particular, type of stimulus such as light, sound, etc., The common type of receptors are, (i) Photoreceptors (in eyes) detect light, (ii) Gustatory receptors (in tongue) detect, taste, (iii) Olfactory receptors (in nose) detect smell, (iv) The rmoreceptors (in skin) detect heat or, cold., Electrical impulse travels in a neuron from, (a) Dendrite Axon  Axonal end  Cell body, (b) Cell body  Dendrite  Axon  Axonal, end, (c) Dendrite  Cell body  Axon  Axonal, end, (d) Axonal end  Axon  Cell body , Dendrite, (c) The neurons carry messages in the form of, electrical signals called electrical impulses or, nerve impulses. The dendrites pick up the, impulses from receptor and pass them to the, cell body, and then along the axon to its end., At the axonal end, electrical impulse sets off, release of some chemicals that crosses the, gap or synapse and start a similar impulse in, dendrite of the next neuron., In a synapse, chemical signal is transmitted, from, (a) dendritic end of one neuron to axonal end, of another neuron, (b) axon to cell body of the same neuron, (c) cell body to axonal end of the same neuron, (d) axonal end of one neuron to dendritic end, of another neuron, (d) A microscopic gap between a pair of, adjacent neurons over which nerve impulses, pass when going from one neuron to the next, is called synapse., In a neuron, conversion of electrical signal to, a chemical signal occurs at in, (a) cell body, (b) axonal end, (c) dendritic end, (d) axon, (b) At the axonal end, the electrical impulse, releases small amount of chemical substance, (i.e., acetylcholine) into the synapse. This, chemical substance crosses the gap and starts, a electrical impulse in the dendrite of next, neuron., Which is the correct sequence of the, components of a reflex arc

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Ans., , (a) Receptors  Muscles  Sensory neuron,  Motor neuron  Spinal cord, (b) Receptors  Motor neuron  Spinal cord,  Sensory neuron  Muscle, (c) Receptors  Spinal cord  Sensory, neuron  Motor neuron  Muscle, (d) Receptors  Sensory neuron  Spinal, cord  Motor neuron  Muscle, (d) The pathway taken by nerve impulse in a, reflex action is called the reflex arc. A reflex, action is involuntary action in response to a, stimulus, e.g., coughing, sneezing etc., It follows a specific pathway as given below, Stimulus ,  Re ceptors ,  Spinal cord, Sensory, , 8., , Ans., 9., , Ans., , neurons, , Effector ,  Re ceptors, ( Muscale/ Gland ), , 6., , Ans., , 7., , Ans., , Which of the following statements are true?, (i) Sudden action in response to something in, the environment is called reflex action, (ii) Sensory neurons carry signals from spinal, cord to muscles., (iii) Motor neurons carry signals from, receptors to spinal cord., (iv) The path through which signals are, transmitted from a receptor to a muscle or a, gland is called reflex arc., (a) (i) and (ii), (b) (i) and (iii), (c) (i) and (iv), (d) (i) (ii) and (iii), (c) The (ii) statement is false as sensory, neurons carry signals from receptors to spinal, cord., The (iii) statement is false as motor neurons, carry signals from spinal cord to effectors., Which of the following statements are true, about the brain?, (i) The main thinking part of brain is hind, brain., (ii) Centres of hearing, smell, memory, sight,, etc., are located in fore brain., (iii) Involuntary actions like salivation,, vomiting, blood pressure are controlled by the, medulla in the hind brain., (iv) Cerebellum does not control posture and, balance of the body., (a) (i) and (ii), (b) (i) (ii) and (iii), (c) (ii) and (iii), (d) (iii) and (iv), (c) The cerebrum (part of forebrain) is the, main thinking part of the brain. It coordinates, the voluntary actions of the body. It has, different areas for performing different, functions such as centres of hearing, smell,, memory, etc., The hindbrain consists of pons (takes part in, regulating respiration), cerebellum (helps in, , 10., , Ans., , 11., , Ans., , 27, , maintaining posture and balance of body) and, medulla that controls involuntary actions such, as breathing etc. The midbrain controls reflex, movements., Posture and balance of the body is controlled, by, (a) cerebrum, (b) cerebellum, (c) medulla, (d) pons, (b) Cerebellum controls the voluntary actions,, e.g., posture., Spinal cord originates from, (a) cerebrum, (b) medulla, (c) pons, (d) cerebellum, (b) Spinal cord is a cylindrical structure, enclosed in a bony cage called vertebra!, Column., It begins in continuation with medulla and, extends downwards., The movement of shoot towards light is, (a) geotropism, (b) hydrotropism, (c) chemotropism, (d) phototropism, (d) A growth movement of a plant part in, response to an external stimuli, towards or, away from it is called tropism., Common stimuli in environment are as given, in table below, Stimulus, Type of Tropism, Light, Phototropism, Gravity, Geotropism, Touch, Thigmotropism, Chemical, Chemotropism, The main function of abscisic acid in plants is, to, (a) increase the length of cells, (b) promote cell division, (c) inhibit growth, (d) promote growth of stem, (c) The main function of abscisic acid in plants, in to inhibit growth. The other plant, hormones with their functions are given in the, table below, Phytohormone Function, Auxins, Promote cell elongation,, root formation, cell, division, and, other, physiological processes, Gibberellins, Stimulate, stem, elongation,, stem, germination, and, flowering, (opposite, effect of ABA), Cytokinis, Promotes, cytokinesis,, also helps in breaking, dormancy and regulating

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Abscisic acid, , Ethylene, , 12., , Ans., , 13., , Ans., , 14., , Ans., , 15., , Ans., , 16., , phloem transport., Growth inhibitor, causes, dormancy of seeds, etc., promotes leaf and fruit, fall, helps in stomata, closing to prevent loss of, H2O., Promotes, transverse, growth,, senescence,, abscission of leaves, etc., , Ans., , Which of the following is not associated with, growth of plant?, (a) Auxin, (b) Gibberellins, (c) Cytokinins, (d) Abscisic acid, (d) Abscisic acid is a growth inhibitor, hormone, it reverses the growth promoting, effects of auxins and gibberellins. It causes, dormancy of seeds, wilting of leaves, closing, of stomata, etc., Iodine is necessary for the synthesis of which, hormone?, (a) Adrenaline, (b) Thyroxin, (c) Auxin, (d) Insulin, (b) Iodine is necessary for the synthesis of, thyroxin hormone, deficiency of it in the diet, of a person produces less thyroxin hormone, and causes a disease known as goitre., The main symptom of goitre is that the neck, of the person appears to be swollen (due to, the enlargement of thyroid gland situated in, the neck)., Choose the incorrect statement about insulin, (a) it is produced from pancreas, (b) it regulates growth and development of, the body, (c) It regulates blood sugar level, (d) Insufficient secretion of insulin will cause, diabetes, (b) Pancreas secrete the hormone insulin. Its, function is to regulate blood sugar level;, Deficiency of insulin causes a disease known, as diabetes that is characterized by large, quantities of sugar in blood and even urine., Growth hormone secreted by the pituitary, gland regulates growth and development of, body., Select the mis-matched pair, (a) Adrenaline-Pituitary gland, (b) Testosterone-Testes, (c) Estrogen-Ovary, (d) Thyroxin-Thyroid gland, (c) Adrenaline is secreted by the adrenal, glands, located on top of kidneys. Growth, hormone is secreted by the pituitary gland., , 17., , Ans., , 18., , Ans., , 19., , Ans., 20., , Ans., , 28, , The shape of guard cells changes due to, change in the, (a) protein composition of cells, (b) temperature of cells, (c) amount of water in cells, (d) position of nucleus in the cells, (c) The shape of guard cells changes due to, amount of water in them. The guard cells well, when water flows into them, causing the, stomatal pore to open. Similarly, the pore, closes if the guard cells shrink, due to the loss, of water in then., The growth of tendril in pea plants is due to, (a) effect of light, (b) effect of gravity, (c) rapid cell divisions in tendrillar cells that, are away from the support, (d) rapid cell divisions in tendrillar cells in, contact with the support, (c) Tendrils are the thin thread-like growths, on the stem or leaves of climbing plants., These are sensitive to touch of other objects, (i.e., thigmotropic). When a tendril touches an, object, then the side in contact with object, grows slowly than its other side, (i.e., rapid, ceil divisions in cells that are away from the, support)., This causes the tendril to bend towards the, object by growing towards it, wind around, object and cline to it., The growth of pollen tubes towards ovules is, due to, (a) hydrotropism, (b) chernotropism, (c) geotropism, (d) phototropism, (b) The growth of a pollen tube towards ovule, is induced by a chemical (sugar) substance, secreted by the ripened stigma of flower into, the style towards ovary., It is an example of chernotropism, pollen, grain responds to stimulus by growing a, pollen tube in downward direction, towards, ovule for fertilization., The movement of sunflower in accordance, with the path of sun is due to, (a) phototropism, (b) geotropism, (c) chernotropism, (d) hydrotropism, (a) The movement of a plant part in response, to light is called phototropism, The substance that triggers the fall of mature, leaves and fruits from plants is due to, (a) auxin, (b) gibberellin, (c) abscisic acid, (d) cytokinin, (c) Abscisic acid is responsible for the, formation of layer of abscission. This layer

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21., , Ans., , 22., , Ans., , 23., , Ans., , 24., , Ans., , disconnect the living tissue of leaf from the, other parts., Which of the following statements about, transmission of nerve impulse is incorrect?, (a) Nerve impulse travels from dendritic end, towards axonal end, (b) At the dendritic end electrical impulses, bring about the release of some chemicals, which generate an electrical impulse at the, axonal end of another neuron, (c) The chemicals released from the axonal, end of one neuron cross the synapse and, generate a similar electrical impulse in a, dendrite of another neuron, (d) A neuron transmits electrical impulses not, only to another neuron but also to muscle and, gland cells, (b) The information acquired at the end of the, dendritic tip of a neuron causes a chemical, reaction that produces an electrical impulse., This impulse travels from dendrite to cell, body and then along axon to its end., Involuntary actions in the body are controlled, by, (a) medulla in fore brain, (b) medulla in mid brain, (c) medulla in hind brain, (d) medulla in spinal cord, (c) Medulla is part of hind brain. It controls, the involuntary action and regulate reflex, responses. The other parts of hind brain are, cerebellum and pons., Which of the following is not an involuntary, action?, (a) Vomiting, (b) Salivation, (c) Heart beat, (d) Chewing, (d) Involuntary actions are those actions that, are not under our direct control such as heart, beat. breathing, peristatic movements, etc., These are controlled by medulla., Chewing is under voluntary control and, controlled by lobes present in cerebral cortex., When a person is suffering from severe cold,, he or she cannot, (a) differentiate the taste of an apple from, that of an ice cream, (b) differentiate the smell of a perfume from, that of an agarbatti, (c) differentiate red light from green light, (d) differentiate a hot object from a cold, object., (b) During cold, mucus in nasal passages, becomes too thick, so that odour molecules, can't reach the olfactory receptor cells. Thus,, brain receives no signal identifying the odour,, , 25., , and so the smell of a perfume cannot be, differentiated from that of an agarbatti., What is the correct direction of flow of, electrical impulses?, , (a), , (b), , (c), , (d), , Ans., , 26., , Ans., 27., , Ans., , 28., , 29, , (c) Direction of flow of electrical impulse., Impulse  Dendrite  Cell body  Axon , Release of chemicals that cross synapse , Dendrite of next neuron, Which statement is not true about thyroxin?, (a) Iron is essential for the synthesis of, thyroxin, (b) It regulates carbohydrates, protein and fat, metabolism in the body, (c) Thyroid gland requires iodine to synthesize, thyroxin, (d) Thyroxin is also called thyroid hormone, (a) Iodine is essential for synthesis of thyroxin., Dwarfism results due to, (a) Excess secretion of thyroxin, (b) Less secretion of growth hormone, (c) Less secretion of adrenaline, (d) Excess secretion of growth hormone, (b) Deficiency of growth hormone in, childhood causes dwarfism while excessive, secretion causes gigantism., Deficiency of thyroxin causes goitre., Adrenaline is secreted in small amounts all, the time but is secreted in large amounts to, prepare our body for action during flight or, fight., Dramatic changes of body features associated, with puberty are mainly because of secretion, of, (a) oestrogen from testes and testosterone, from ovary, (b) estrogen from adrenal gland and, testosterone from pituitary gland

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(c) testosterone from testes and estrogen, from ovary, (d) testosterone from thyroid gland and, estrogen from pituitary gland, Ans., Gland, Hormone, Testes, Testosterone, (only in, males), , Ovaries Oestrogen, (only in, females), , Progesterone, , 29., , Ans., , 30., , Ans., , 31., , Ans., , 32., , Function, To, control, the, development, of, male sex organs and, male features as, deep voice, etc., i.e.,, changes associated, with puberty., To, control, the, development, of, female sex organs, and female features, as soft skin, etc., To control uterus, changes, during, menstrual cycle and, helps, in, maintenance, of, pregnancy., , Ans., , 33., , Ans., , A doctor advised a person to take an injection, of insulin because, (a) his blood pressure was low, (b) his heart was beating slowly, (c) he was suffering from goitre, (d) his sugar level in blood was high, (d) The person having high sugar level in, blood is called a diabetic. Such persons are, advised to take less sugar in diet, reduce, weight, exercise regularly. Persons with, severe diabetes (high sugar level in blood) are, treated by giving injections of insulin., The hormone which increase the fertility in, males is called, (a) oestrogen, (b) testosterone, (c) insulin, (d) growth hormone, (b) Testosterone is the male sex hormone. It, regulates male accessory sex organs. It is, responsible for secondary sexual characters, like moustache, beard, etc., thus, increasing, fertility in males., Which of the following endocrine glands is, unpaired?, (a) Adrenal, (b) Testes, (c) Pituitary, (d) Ovary, (c) There are two adrenal glands, one on top, of each kidney that make adrenaline, hormone. Testes are paired glands presents in, males, secretes male sex hormone., , Pituitary gland is present just below the brain, and is unpaired. It is also called master gland, as it secretes a number of hormones. Ovaries, are paired glands present in females, secretes, female sex hormones., Junction between two neurons is called, (a) cell junction, (b) neuro muscular junction, (c) neural joint, (d) synapse, (d) Junction between two neurons is coiled, synapse., Cell junction - junction between neighbouring, cells, Neuromuscular junction-connects nervous, system to muscular system, In humans, the life processes are controlled, and regulated by, (a) reproductive and endocrine systems, (b) respiratory and nervous systems, (c) endocrine and digestive systems, (d) nervous and endocrine systems, (d) In human beings, nervous system and, endocrine system work together to control, and coordinate all the activities. Both these, systems consist of a number of organs that, work together in a systematic way, , Short Answer Type Questions, , 30, , 34., , Label the parts (a), (b), (c) and (d) and show, the direction or flow of electrical signals in, given figure., , Ans., , (a) Sensory neuron, (b) Spinal cord (CNS), (c) Motor neuron, (d) Effector (muscle in arm)

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Ans., , 38., , 35., , Ans., , 36., , Name the plant hormones responsible for the, following, (a) elongation of cells, (b) growth of stem, (c) promotion of cell division, (d) falling of senescent leaves, (a) Auxin-elongation of cells, (b) Gibberellin-growth of stem, (c) Cytokinin-promotion of cell division, (d) Abscisic acid-falling of senescent leaves, Label the endocrine gland in figure, , Ans., 39., , Ans., Ans., , 37., , The endocrine glands, follow, Glands, (a) Pineal gland, side of brain, (b) Pituitary gland, (c) Thyroid gland, windpipe, (d) Thymus, , and its location are as, Location, Attached to dorsal, 40., , Just below the brain, Attached, to, the, , Ans., , Lower part of the, neck and upper part, of chest, , In figure (a), (b) and (c), which appears more, accurate and-why?, , 41., , Figure (a) is more accurate. The roots of a, plant always grow downwards in response the, gravity to make sure they find soil and water., On the other hand, the stem always grows up, away from gravity pull to make sure they will, get light. Both these conditions are shown in, figure (a)., Label the part of a neuron in Figure below., , (a) Dendrite, (b) Cell body, (c) Axon, (d) Nerve ending, Match the terms of column I with those of, column II., Column I, Column II, A. Olfactory receptors, 1. Tongue, B. Thermo receptors, 2. Eye, (temperature receptors):, C. Gustatoreceptors, 3. Nose, D. Photoreceptors, 4. Skin, The matching of the column I with column II, Column I, Column II, A. Olfactory receptors, Nose, B. Thermo receptors, Skin, C. Gustatoreceptors, Tongue, D. Photoreceptors, Eye, What is a tropic movement? Explain with an, example., The movement of a plant in the direction of a, stimulus or away from it is called tropic, movement or tropism. It is said to be positive, if it is directed towards the source of stimulus, and negative if directed away from the source, stimulus. e.g., geotropism, the tropic respose, towards gravity. When a growing portion of a, plant is placed horizontally, the stem tip, grows away from the pull of gravity. While the, root tip grows towards it. Thus, the stem is, said to be negatively geotropic and the root, positively geotropic., What will happen if intake of iodine in our, diet is low?, , Iodine (5 necessary for the thyroid gland to, make thyroxin hormone., This, is a case of geotropism, i.e., response of, plants to gravity., , Ans., , 31, , When iodine intake is low, following may, happen, (a) Release of thyroxin from thyroid gland will, be less. This will affect the metabolism of

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42., , carbohydrate, protein and fat and thus slow, down the growth of body, (b) A person might suffer from goitre. One of, the symptom of this disease is a swollen neck, What happens at the synapse between two, neurons?, , Ans., , The gap between the ending of an axon, (synoptic terminals) and the dendrite of, another neuron is called a synapse. A, chemical substance is released at axonal end, that passes through it., Ans., , 43., , Ans., , 44., , (a) Pituitary Hypothalamus gland present in, brain releases hormones that regulate the, secretion of pituitary glands., (b) Pancreas It is a digestive gland as well as it, secretes the pancreatic juice for digestion of, food. It also secretes hormones as insulin., (c) Adrenal Adrenal glands are located on the, top of two kidneys., (d) Testes These are the glands which are, present only in males and secretes male sex, hormone, testosterone., , Long Answer Type Questions, 45., , When an electrical impulse reaches the end of, the axon, it causes the axon bulb to release a, chemical which diffuses across the synapse, and stimulates the dendrites of adjacent, neuron. These dendrites in turn send, electrical signals to their cell body to be, carried along the axon., Answer the following, (a) Which hormone is responsible for the, changes noticed in females at puberty?, (b) Dwarfism results due to deficiency of, which hormone?, (c) Blood sugar level rises due to deficiency of, which hormone?, (d) Iodine is necessary for the synthesis of, which hormone?, (a) Oestrogen At the onset of puberty in, females, the ovaries begin to secrete this, hormone. It produces secondary sexual, characters in females and prepares the body, for pregnancy., (b) Growth Hormone It is secreted by the, anterior lobe of pituitary, it promotes growth, and development of body., (c) Insulin It is secreted by pancreas. It, controls the rate of oxidation of glucose, helps, liver and muscle (cells to absorb glucose from, the blood)., (d) Thyroxine it is secreted by the thyroid, gland. It regulates the carbohydrate, protein, and fat metabolism in the body., Answer the following, (a) Name the endocrine gland associated with, brain?, (b) Which gland secretes digestive enzymes as, well as hormones?, (c) Name the endocrine gland associated with, kidneys?, (d) Which endocrine gland is present in males, but not in females?, , Ans., , 46., Ans., , Draw the structure of a neuron and. explain, its function., Neurons or nerve cells are the units which, make up the nervous system. These are the, structural and functional unit of the nervous, system. It is the largest cell in the body. It, carry messages over large distance in the, body quickly. The messages are in the form of, electrical signals called electrical impulses or, nerve impulses., A neuron is shown in figure below, , A neuron (or nerve ceil} has three, components, (i) Cell body It contains cytoplasm and a, nucleus, (ii) Dendrites These are shorter fibres on the, body of a neuron., (iii) Axon The longest fibre on cell body of a, neuron., The axon has an insulating and protective, sheath of myelin around it. A number of long, and thin fibres stretch out from the cell body, of a neuron called nerve fibres., What are the major parts of the brain?, Mention the function of different parts., Brain is the most important coordinating, centre in the body. It has three major parts or, regions namely the fore-brain, mid-brain and, hind-'brain., , Parts, Fore-brain, Cerebrum, , 32, , Functions, Main thinking part of the, brain

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(ii) Spinal cord It is a long cylindrical structure., It begins from the medulla oblongata and, extends downwards. It is enclosed in a bony, cage called Verebral column that protects it., It is also sorrounded by meninges. It is, concered with spinal reflex actions and, conduction of nerve impulses to and from the, brain., Peripheral Nervous System (PNS), It includes the following, (i) Cranial nerves 12 pairs that emerge from, the brain., (ii) Spinal nerves 31 pairs that arise from the, spinal cord and spread throughout the body., (iii) Visceral nerves They are special kind of, nerves mostly arise from the spinal cord and, are connected to the internal organs of the, body. They carry both sensory and motor, neurons. The PNS works according to our will,, i.e., it is related to voluntary acts., 48., Mention one function for each of these, hormones, (a) Thyroxin, (b) Insulin, (c) Adrenaline, (d) Growth hormone, (e) Testosterone, Hormone, Function, (a) Thyroxin, It regulates carbohydrate,, protein and fat matabolism in, the body so as to provide the, best balance for growth., (b) Insulin, It helps in regulating blood, sugar levels., (c) Adrenaline, Increases heart rate and supply, of blood to various organs., (d) Growth hormone It regulates growth and, development in the body., (e) Testosterone, Controls the changes of body, features, associated, with, puberty in male., , Cerebral hemispheres Intelligence and voluntary, actions, Olfactory lobes, , Centres of smell, , Diencephalon, , Has centres of hunger,, thirst, etc, , Motor areas, , Instructs muscles to do, various types of jobs, , Mid-brain, Tectum, , Controls reflex movements, of the neck, head and trunk, in response to visual and, auditory stimuli, , Cerebral peduncle, , Also controls the reflex, movements of the 'eye, muscles, changes in pupil, size and shape of the eye, lens, , Hind-brain, Pons, , Regulate respiration, Relays information between, the cerebellum and the, cerebrum, Maintaining, posture and balance of the, body, , Cerebellum, , Enables us to make precise, and accurate movements, , Medulla, , Controls involuntary actions, as breathing, etc, Controlling, centre, for, reflexes such as swallowing,, coughing, vomiting, etc, , 47., , Ans., , What constitutes the central and peripheral, nervous systems? How are the components of, central nervous system protected?, The central nervous system consists of the, brain and the spinal cord, (i) Brain It is the main coordinating centre in, the body It is lodged in the brain box or, cranium which protects it. It is covered by, membranes called meanings, which also help, to protect it. The space between the, membranes and the brain is filled with a, cerebrospinal fluid which protect the brain, from mechanical shock. The brain is broadly, divided into three regions fore-brain, midbrain and hind-brain., , 49., , Name various plant hormones. Also give their, physiological effects on plant growth and, development., Plant, Physiological effect, hormone, A. Auxin,  Synthesized in the young tip of, roots and shoots. It diffuses, towards the shady side of plant, which stimulates the cells to, grow longer, resulting in bending, of shoot toward light,  Promotes cell elongation and, division,  Play important role in, , 33

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coordination in human beings.' Justify the, statement., , formation of root, and seedless fruit, B. Bibberellin,  Help in growth of stem and, flower,  Help in germination of seed, C. Cytokinins,  Promote cell division and, delay leaf ageing,  Also stimulate leaf expansion, D., Abscisic  Growth inhibitor, Acid,  Reverses, the, growth, promoting effects of auxins and, gibberellins, E. Ehtylene,  Promotes transverse growth,  Essential for fruit ripening,, promotes,  senescence and abscission of, leaves, 50., Ans., , Receptors  Nervous system  Effector, (Glands/muscles) Release of Hormone, Ans., , What are reflex actions? Give two examples., Explain a reflex arc., Reflex action is a rapid, automatic response to, a stimulus which is not under the voluntary, control of the brain i.e., it is an involuntary, action. It is a simple form of behaviour in, which the same stimulus produces the same, response every time. e.g.,, (i) If we unknowingly touch a hot plate, we, immediately move our hand away from it., (ii) Moving our foot away on stepping, something sharp, Other examples are knee jerk, coughing,, yawning, sneezing etc., The pathway taken by nerve impulse in a, reflex action is called the reflex arc, , 52., Ans., , Reflex arcs have evolved in animals because, the thinking process of brain is not fast, enough. However, even after complex neuron, networks have come into existence, reflex are, continue to be more efficient for quick, responses., 51., , 'Nervous and hormonal systems together, perform the function of control and, , 34, , The working together of various organs of, human being in a systematic, controlled and, efficient way to produce a proper response to, various stimuli is known as coordination. In, humans, the nervous and hormonal system, together, perform, this, control, and, coordination., Nervous System consists of receptors that, receives the stimulus from surrounding, environment and send the message conveyed, by them to the spinal cord and brain in form, of electrical impulses through the sensory, nerves. The motor nerves then transmit the, response to the 'effector'. The effector are, mainly the muscles and glands of our body,, Thus, endocrine glands secreting hormones, are directly or indirectly controlled by the, nervous system., Hence, control and coordination in humans, (or animals) depends on two things for, transmitting information i.e., chemical signals, of hormones and nerve impulses., If they depended only on nerve impulses, through nerve cells, a limited range of tissues, would be stimulated. Since, they get, additional chemical signals as well, a large, number of tissues are stimulated. This is why, animals can show a wide - range of response, to stimulus., How does chemical coordination take place in, animals?, Chemical coordination in animals is, performed by hormones that are chemical, messengers. Different endocrine glands, secrete different hormones to regulate, various processes., These hormones are released into the blood, which carry them to specific tissues or organs, called target tissues/organs. In the target, tissue, hormone triggers a particular, biochemical or physiological activity., The hormones are of different types and, perform different function. Their timing of, release and their amount is gulated by, feedback mechanism.

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53., , Why is the flow of signals in a synapse from, axonal end of one neuron to dendritic end of, another neuron but not the reverse?, , 7., , 8., , When an electrical signal reaches the axonal, end of a neuron, it releases a chemical, substance., Ans., , 9., , The synapse actually act like a one-way valve, because the chemical substance is present, only on one side of the gap. This chemical, diffuses towards the dendrite end of next, neuron where it generates an electrical signal., Since, the chemicals are absent at the, dendritic end of neuron, the nerve impulse, can go across only from one side (which, contains the chemical substance). In this way,, it is ensured that nerve impulses travel in only, one direction (through of particular set of, neurons)., , 10., , 11., , 12., , 13., , Multiple Choice Questions, 1., , 2., , 3., , 4., , 5., , 6., , Name the hormone which is commonly, termed 'birth hormone' and 'milk ejecting, hormone'., (a) oxytocin, (b) vasopressin, (c) thyroxine, (d) luteinizing hormone., The directional movement or orientation of a, plant part in response to light is termed, (a) chemotropism, (b) phototropism, (c) thigmotaxis, (d) photoperiodism., Name the plant hormone which is termed, growth inhibitor., (a) auxin, (b) gibberellin, (c) abscisic acid, (d) ethylene., Seismonastic movements are shown by which, plant?, (a) Indian telegraph plant, (b) 'touch-me-not' plant, (c) cucumber plant, (d) rose plant., Which plant hormone plays a role in apical, dominance in plants?, (a) auxin, (b) abscisic acid, (c) ethylene, (d) gibberellin., Bolting in some plants is induced by artificial, treatment of which plant hormone?, (a) auxin, (b) ethylene, , 14., , 15., , 16., , 17., , 18., , 19., , 20., , 35, , (c) gibberellin, (d) abscisic acid., Name the organism which lacks nervous, system., (a) grasshopper, (b) Hydra, (c) human being, (d) plant., Name the part of nervous system which is, generally involved in reflex actions., (a) brain, (b) ganglion, (c) pons, (d) spinal cord., In plants, growth occurs by, (a) permanent tissue, (b) meristematic tissue, (c) ground substance, (d) bark., Cerebral hemispheres are the centres of, (a) posture and equilibrium, (b) reflex actions, (c) thinking and memory, (d) all of these., Phytochrome pigment is present in, (a) stems, (b) leaves, (c) fruits, (d) flowers., Which of the following is not a reflex action?, (a) coughing, (b) blinking of eyes, (c) knee-jerk, (d) weeping., Medulla oblongata of hind brain controls, (a) rate of heat beat, (b) equilibrium, (c) thinking, (d) vision., Name the gland having both exocrine and, endocrine regions., (a) thyroid, (b) pancreas, (c) adrenal gland, (d) pituitary., Auxins inhibit the growth of, (a) apical buds, (b) lateral axillary buds, (c) parthenocarpic development of fruits, (d) roots of cuttings., Gibberellins were first isolated from, (a) algae, (b) bacteria, (c) roots of higher plants, (d) fungus., Cut leaves remain green for longer time when, dipped in, (a) cytokinins, (b) ethylene, (c) gibberellin, (d) auxins., Ethylene is a, (a) gaseous hormone (b) gaseous enzyme, (c) liquid hormone, (d) solid hormone., Production of seedless fruits is referred to as, (a) parthenocarpy, (b) parthenogenesis, (c) endocarpy, (d) exocarpy., Phytohormone which is a growth inhibitor is, (a) abscisic acid, (b) gibberellin, (c) auxin, (d) IAA.

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21., , 22., , 23., , 24., , 25., , 26., , 27., , 28., , 29., , 30., , 31., , Which statement is not true about thyroxine?, (a) Iron is essential for the synthesis of, thyroxine., (b) It regulates carbohydrates, protein and fat, metabolism in the body., (c) Thyroid gland requires iodine to synthesize, thyroxine., (d) Thyroxine is also called thyroid hormone., _______is a naturally occurring cytokinin., (a) zeatin, (b) kinin, (c) kinetic, (d) ribotin., Cell elongation in plants is caused by, (a) abscisic acid, (b) gibberellins, (c) florigens, (d) ethylene., Apical dominance in higher plants is due to, (a) balance between auxins and cytokinins, (b) enzyme activity, (c) supply of carbohydrates, (d) photoperiodism., Which of the following is not a ductless gland?, (a) adrenal, (b) thyroid, (c) pituitary, (d) liver., Which of the following effects of auxins on, plants is the basis for commercial application?, (a) Callus formation,, (b) Curvature of stem., (c) Induction of root formation in stem, cuttings., (d) All of these., Apical dominance means, (a) suppression of growth of apical buds due, to presence of axillary buds, (b) suppression of growth of axillary buds due, to presence of apical bud, (c) stimulation of apical bud growth by, removal of axillary buds, (d) inhibition of growth of axillary buds by, removal of apical bud., Bending of stem towards the sunlight in, plants is due to, (a) unequal distribution of auxins, (b) uniform occurrence of gibberellins, (c) inhibition of cytokinin synthesis, (d) unequal distribution of cytokinins and, gibberellins., Leaf fall can be induced by, (a) florigens, (b) auxins, (c) cytokinins, (d) abscisic acid., Which of the following is a cytokinin?, (a) leucine, (b) phytochrome, (c) ethylene, (d) zeatin., Cytokinins are known to, (a) help in retention of chlorophyll, (b) promote formation of abscission layer, (c) inhibit cytoplasmic movement, , 32., , 33., , 34., , 35., , 36., , 37., , 38., , 39., , 40., , 41., , 42., , 43., , 36, , (d) influence water transport., The effect of duration of light period on, flowering is called, (a) phototropism, (b) photoperiodism, (c) photorespiration, (d) photo oxidation., Growth of the plant or plant part towards the, earth is called, (a) hydrotropism, (b) geotropism, (c) phototropism, (d) thigmotropism., Opening and closing of flowers represent a, kind of, (a) nastic movement, (b) geotropism movement, (c) nutation, (d) autonomic movement., The layer which separates leaves and fruits, from plants is called as, (a) abscission, (b) germinal, (c) hypogeal, (d) epigeal., Cretinism in young children is due to lack of, (a) vitamin D, (b) growth hormone, (c) thyroid hormones (d) insulin., The main function of parathyroid in body is to, (a) built teeth, (b) form calcium compounds, (c) maintain proper amount of calcium and, phosphorus in the blood, (d) build bones., The fight or flight response is developed by, hormones of the, (a) hypothalamus, (b) adrenal medulla, (c) adrenal cortex, (d) pancreas., Which part of human brain is more developed, in comparison of others?, (a) cerebrum, (b) cerebellum, (c) optic lobes, (d) medulla oblongata., Pons varolii found on the ventral side of, medulla oblongata connects two, (a) cerebral hemispheres, (b) lateral lobes of cerebellum, (c) optic lobes, (d) olfactory lobes,, Two systems which exert opposite influence, on the same organs or set of organs are, (a) endocrine and exocrine gland systems, (b) muscular and nervous systems, (c) endocrine and nervous systems, (d) sympathetic and parasympathetic, systems., The chemical transmitter of nerve impulses is, (a) cholinesterase, (b) hexokinase, (c) acetylcholine, (d) acetyl co-A., Parasympathedc nervous system helps in, (a) dilation of pupils, (b) increase in blood pressure

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44., , 45., , 46., , 47., , 48., , 49., , 50., , 51., , 52., , 53., , 54., , 55., , 56., , 57., , 58., , (c) increase in the rate of heart beat, (d) contraction of smooth muscles of, alimentary canal., Due to stimulation of sympathetic nervous, system, (a) tear secretion increases, (b) saliva secretion decreases, (c) sweat secretion increases, (d) all of these., Cakitonin is secreted by _______ gland., (a) parathyroid, (b) thyroid, (c) adrenal, (d) pancreas., Pregnancy hormone is, (a) oxytocin, (b) vasopressin, (c) progesterone, (d) testosterone., Islets of Langerhans secrete insulin and, (a) glucagon, (b) epinephrine, (c) lipase, (d) none of these., Which of the following is not an involuntary, action?, (a) vomiting, (b) salivation, (c) heart beat, (d) chewing., The β – cells of pancreas secrete, (a) insulin, (b) thyroxine, (c) glucagon, (d) none of these., The longest cell in human body is, (a) nerve cell, (b) liver cell, (c) reproductive cell, (d) muscle fibre., FSH is secreted by, (a) posterior lobe of pituitary gland, (b) middle lobe of pituitary gland, (c) anterior lobe of pituitary gland, (d) none of the above., Excess secretion of parathormone results in, (a) osteoporosis, (b) acromegaly, (c) goitre, (d) none., The hormone that helps in the reabsorption, of sodium and water in the body is, (a) testosterone, (b) progesterone, (c) aldosterone, (d) all of these., Master gland in the body is, (a) thyroid, (b) adrenal, (c) islets of Langerhans (d) pituitary., The hormone that helps in the implantation of, zygote is, (a) testosterone, (b) insulin, (c) prolactin, (d) progesterone., Cortisol is secreted by, (a) medulla of pituitary (b) medulla of adrenal, (c) cortex of adrenal, (d) cortex of thyroid., Over secretion of growth hormone leads to, (a) gigantism, (b) dwarfism, (c) acromegaly, (d) both (a) & (c)., Which of the following protects the brain, from shocks?, , 59., , 60., , 61., , 62., , 63., , 64., , 65., , 66., , 67., , 68., , 69., , 70., , 37, , (a) pons, (b) cerebrospinal fluid, (c) duramater, (d) arachnoid membrane., Gustatory receptors detects, (a) sound, (b) smell, (c) taste, (d) sight., Which one of the following does not secrete, any hormone?, (a) thyroid, (b) ovary, (c) testes, (d) spleen., Roots are, (a) positively geotropic, (b) negatively geotropie, (c) positively phototropic, (d) none of these., Stem is, (a) positively geotropic, (b) negatively phototropic, (c) negatively geotropic, (d) none of these., Response of plant roots towards water is, called, (a) chemotropism, (b) phototropism, (c) hydrotropism, (d) geotropism., Plants cannot think because they do not have, (a) nervous system, (b) digestive system, (c) circulatory system, (d) excretory system., Any change in the environment to which an, organism responds is called, (a) response, (b) stimulus, (c) tropism, (d) tonocity., Cavities of brain are called, (a) auricles, (b) ventricles, (c) coelom, (d) lumen., Breathing is controlled by which part of the, brain?, (a) medulla oblongata, (b) hypothalamus, (c) lungs, (d) cerebrum., Which of the following are associated with, protein synthesis?, (a) axon, (b) neurofibrils, (c) dendrons, (d) Nissl's granules., Which part of the brain regulates the body, temperature?, (a) hypothalamus, (b) thalami, (c) pituitary, (d) medulla oblongata., Broca's area is concerned with, (a) smell, (b) learning and reasoning, (c) vision

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71., , 72., , 73., , 74., , 75., , 76., , 77., , 78., , 79., , 80., , 81., , 82., , (d) speech., Primary visual area lies in, (a) frontal lobe, (b) parietal lobe, (c) occipital lobe, (d) temporal lobe., Outermost meningeal membrane is, (a) dura mater, (b) pia mater, (c) arachnoid membrane, (d) myelin sheath., Which of the following is a stress hormone?, (a) auxin, (b) gibberellin, (c) cytokinin, (d) ABA., Which of the following increases the, intermodal length in genetically dwarf plants?, (a) auxin, (b) gibberellin, (c) cytokinin, (d) ABA., The term hormone was coined by, (a) Starling, (b) Went, (c) Yabuta, (d) Wilson., Diabetes mellitus occurs due to deficiency of, which hormone?, (a) ADH, (b) glucagon, (c) insulin, (d) thyroxine., Ductless glands are known as, (a) exocrine glands, (b) endocrine glands, (c) heterocrine glands (d) alveolar glands., By which gland the somatostatin is secreted?, (a) pineal, (b) hypothalamus, (c) thyroid, (d) pituitary., The gland which degenerates with, advancement of age and disappears by, middle age is, (a) thyroid, (b) pituitary, (c) thymus, (d) prostate., Which of the following statements is correct, about receptors?, (a) Gustatory receptors detect taste while, olfactory receptors detect smell., (b) Both gustatory and olfactory receptors, detect smell., (c) Gustatory receptors detect smell and, olfactory receptors detect taste., (d) Olfactory receptors detect taste and, gustatory receptors smell., Electrical impulse travels in a neuron from, (a) dendrite  axon  axonal end  all body, (b) cell body  dendrite  axon  axonal, end, (c) dendrite  cell body  axon  axonal, end, (d) axonal end  axon  cell body , dendrite., In a synapse, chemical signal is transmitted, from, (a) dendrite end of one neuron to axonal end, of another neuron., , 83., , 84., , 85., , 86., , 87., , 88., , 89., , 38, , (b) axon to all body of the same neuron., (c) cell body to axonal end of the same, neuron., (d) axonal end of one neuron to dendritic end, of another neuron., In a neuron conversion of electrical signal to a, chemical signal occurs at in, (a) cell body, (b) axonal end, (c) dendritic end, (d) axon., Which is the correct sequence of the, components of a reflex arc?, (a) receptors  muscles  sensory neuron , motor neuron  spinal cord, (b) receptors  motor neuron  spinal cord,  sensory neuron  muscles, (c) receptors  spinal cord  sensory, neuron  motor neuron  muscles, (d) receptors  sensory neuron  spinal cord,  motor neuron  muscles., Which of the following statements are true?, (i) Sudden reaction in response to stimulus is, called reflex action., (ii) Sensory neurons carry signals from spinal, cord to muscles., (iii) Motor neurons carry signals from, receptors to spinal cord., (iv) The path through which signals are, transmitted from a receptor to a muscle or a, gland is called reflex arc., (a) (i) and (ii), (b) (i) and (iii), (c) (i) and (iv), (d) (i), (ii) and (iii)., Which of the following statements are true, about the brain?, (i) The main thinking part of brain is hind, brain., (ii) Centers of hearing, smell, memory, sight,, etc. are located in for brain., (iii) Involuntary actions like salivation,, vomiting, blood pressure are controlled by the, medulla in the hind brain., (iv) Cerebellum does not control posture and, balance of the body., (a) (i) and (ii), (b) (i), (ii) and (iii), (c) (ii) and (iii), (d) (iii) and (iv)., Posture and balance of the body is controlled, by, (a) cerebrum, (b) cerebellum, (c) medulla, (d) pons,, Spinal cord originates from, (a) cerebrum, (b) medulla, (c) pons, (d) cerebellum., Select the incorrect statement about insulin., (a) It is produced from pancreas.

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90., , 91., , 92., , 93., , 94., , 95., , 96., , 97., , (b) It regulates growth and development of, the body., (c) It regulates blood sugar level., (d) Insufficient secretion of insulin will cause, diabetes., Select the mis-matched pair., (a) adrenaline, - pituitary gland, (b) testosterone, - testes, (c) estrogen, - ovary, (d) thyroxine, - thyroid gland., The growth of tendril in pea plants is due to, (a) effect of light, (b) effect of gravity, (c) rapid cell divisions in tendrillar cells that, are away from the support, (d) rapid cell divisions in tendrillar cells in, contact with the support, The substance that triggers the fall of mature, leaves and fruits from plants is due to, (a) auxin, (b) gibberellin, (c) abscisic acid, (d) cytokinin., Involuntary actions in the body are controlled, by, (a) medulla in fore brain, (b) medulla in mid brain, (c) medulla in hind brain, (d) medulla in spinal cord., When a person is suffering from severe cold,, he or she cannot differentiate, (a) taste of an apple from that of an ice cream, (b) smell of a perfume from that of an, agarbatti, (c) red light from green light, (d) a hot object from a cold object., Dramatic changes of body features associated, with puberty are mainly because of secretion, of, (a) oestrogen from testes and testosterone, from ovary, (b) estrogen from adrenal gland and, testosterone from pituitary gland, (c) testosterone from testes and estrogen, from ovary, (d) testosterone from thyroid gland and, estrogen from pituitary gland., A doctor advised a person to take an injection, of insulin because, (a) his blood pressure was low, (b) his heart was beating slowly, (c) he was suffering from goitre, (d) his sugar level in blood was high., The hormone which increases the fertility in, males is called, (a) oestrogen, (b) testosterone, (c) insulin, (d) growth hormone., , 98., , 99., , 100., , 1., 2., 3., 4., 5., 6., 7., 8., 9., 10., 11., 12., 13., 14., , 15., 16., 17., 18., 19., 20., , 39, , Which of the following endocrine glands is, unpaired?, (a) adrenal, (b) testes, (c) pituitary, (d) ovary., Deficiency of vasopressin causes, (a) diabetes mellitus, (b) goitre, (c) diabetes insipidus (d) myxoedema., If the pituitary gland of an adult is surgically, removed, which of the following endocrine, glands will be less affected?, (a) adrenal cortex, (b) adrenal medulla, (c) thyroid, (d) gonads., , Neurons that carry information to an effector, are called ____ neurons., The chemicals stored in synaptic vesicles are, called ____., The _____ of the neuron secretes the neurotransmitter substance., Touch me not shows ________ movement., Temporal lobe of cerebrum is region for, ________reception., The functional junction between two neurons, is called ______., Sneezing is a _______., The nervous system uses ________ to, transmit messages., A feedback mechanism regulates the action of, the________., Central nervous system includes ________, and _____., The control and coordination in plants is, performed by certain chemicals called_____., The movement of plant or plant part due to, gravity is called ________., ________ are chemical messengers secreted, by endocrine glands., ________ stimulates the rate of cellular, oxidation and metabolism of carbohydrates,, proteins and fats., Animals receive external information through, specialized sense organs called __________., Human brain is covered by _____ part of skull., Spinal cord is the extension of __________., ________ nerves carry impulses from, receptors to brain., Spinal cord encloses a cavity the ________, that contains ________., Photoperiodism is controlled by ________.

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1., 2., 3., , 4., 5., 6., 7., 8., 9., 10., 11., 12., 13., 14., 15., 16., 17., , 18., 19., 20., , From a functional perspective, the nervous, system provides slow, long-term coordination., Only the vertebrates have a nervous system., The propagation of a nerve impulse is due to, changes in the permeability of the nerve cell, membrane that allow for a voltage difference, across the membrane., The central nervous system consists of the, brain and spinal cord., Functioning of various organs in uniformity is, called coordination., Thyroxine regulates the blood-sugar., Brain is the structural and functional unit of, nervous system., Feeling hunger is a reflex action., All animals have complex nervous system., One-celled organisms can respond to stimuli., The human brain is the largest of all animals., The growth of pollen tube towards ovary, shows chemotropism., The nervous system is closely associated with, every system in your body., Klinostat is an apparatus by which effect of, gravity can be studied., There is only one type of neuron found in the, human nervous system., The plant hormone named after the bakane, disease caused by fungus is gibberellin., Seismonastic movements involve diurnal, variation in the position of flowers and leaves, in day and night., The growth of pollen tube shows, hydrotropism., Auxin hormone is synthesized by the, meristematic tissue at the tip of the stem., The roots of a plant are positively geotropic, while stem is negatively geotropic., , 2., , 3., , 4., , 5., , 6., , 7., , 8., , 9., , 10., , 11., Directions: In each of the following questions, a, statement of assertion is given and a corresponding, statement of reason is given just below it. Of the four, statements, given below, mark one as the correct, answer, (a) If both Assertion and Reason are true and Reason, is the correct explanation of Assertion, (b) If both Assertion and Reason are true but Reason, is not the correct explanation of Assertion, (c) If Assertion is true but Reason is false, (d) If both Assertion and Reason are false., 1., Assertion: Nerve impulses are carried from, gustatory cells of taste buds to the brain., , 1., 2., 3., 4., , 40, , Reason: Taste centre in brain is responsible, for perceiving the taste sensation., Assertion: Taste buds are called the sense, organs for olfaction., Reason: Taste buds bear olfactory receptor, cells which get stimulated by certain chemical, substances., Assertion: The chemicals stored in the, synaptic, vesicles, are, termed, as, neurotransmitters., Reason: Synaptic vesicles release these, chemicals in the synaptic cleft., Assertion: Brain and spinal cord has a, common covering., Reason: Both the brain and spinal cord, possess meanings., Assertion: Cerebrospinal fluid (CSF) is present, throughout the central nervous system., Reason: CSF has no such function., Assertion: A person has lost most of its, intelligence, memory and judgment., Reason: He has been operated for a tumor, located in the cerebrum., Assertion: Nerve conduction is the one way, conduction., Reason: Nerve impulse is transmitted from, dendrite terminals to axon terminals., Assertion: Auxins are found in the growing, tips of the plant., Reason: The concentration of auxin is highest, at the tip of the root., Assertion: Phototropism in plants is caused by, auxin., Reason: The plant showing bending has more, elongated cells on the illuminated side., Assertion: Gibberellins, when applied to, dwarf plant, increase the length of the plant., Reason: Gibberellins induce intermodal, growth in some genetically dwarf varieties., Assertion: Ethylene is a gaseous hormone., Reason: Ethylene is formed in almost all plant, parts., , Which part of the plant shows positive, geotropism and why?, Define the term photoperiodism., What is parthenocarpy?, What are tropic movements?

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5., , 6., 7., , 8., 9., 10., 11., 12., 13., 14., 15., 16., 17., 18., 19., 20., , 21., 22., 23., , 24., 25., , 26., 27., 28., 29., 30., , Name three disorders which occur due to, improper secretion of growth hormone from, anterior lobe of pituitary., Name the endocrine gland which secretes, neurohormones., Write the full form of ECG and name the, instrument used for recording ECG of a, person., What is phytohormone? Name any two, phytohormones., Why endocrine glands release their secretions, into the blood?, Why movements in plants are not as apparent, as in case of animals?, Which is the posterior most part of the brain?, Name the cavity present in it., What is cranium? What is its function?, What are inhibitory hormones?, Write the functions of any one part of hind, brain., Give the function of any one hormone, secreted by the anterior lobe of pituitary., Name the three major regions of the human, brain., Distinguish, between, voluntary, and, involuntary actions of our body., Why is the use of iodized salt advisable?, Explain the cause of shoots of the plant, bending towards light., “There is a need of a system for control and, coordination in an organism”. Justify the, statement., What are nastic and curvature movements?, Give one example of each., Define chemotropism., Which one of the following actions is an, example of non-directional movement?, (i) Movement in the touch-sensitive plant., (ii) Movement in human leg., Name two plant hormones that help in stem, growth., Name the hormone responsible for, (i) Phototropic movement of plant., (ii) Promoting cell division in plants., What are gustatory receptors?, Name the structural and functional unit of, human nervous system., What could be the possible disadvantage if, reflex action were controlled by the brain?, Why is pituitary gland called master gland?, Name one endocrine gland which performs, dual function., , 1., 2., , 3., , 4., , 5., , 6., 7., 8., 9., 10., 11., , 12., , 41, , Define 'hormones'. Name the hormone, secreted by thyroid. Write its function., (i) Draw the structure of a neuron and label, the nucleus, dendrite, cell body, and axon on, it., (ii) Name the part of neuron, (a) where information is acquired., (b) through which information travels as an, electrical impulse., (i) What is, (a) phototropism and, (b) geotropism., (ii) Mention the role of each of the following, plant hormones., (a) Auxin, (b) Abscisic acid., Which animal or plant hormone is associated, with the following?, (i) Decreases sugar level of blood., (ii) Develop secondary sexual characters at, puberty in boys., (iii) Inhibits growth of plants., (iv) Ripening of fruits., (v) Dwarfism, (vi) Goitre., (i) What are plant hormones? Give one, example of a plant hormone that promotes, growth., (ii) Name the parts labeled A, B and C in the, diagram given below. Write one function of, each part., , Give protective features of the nervous, system., Discuss different tropic movements., How do neurons transmit information?, Give the difference between sensory and, motor nerves., Give the characteristics of hormones., What health disorder may occur if the, following hormones are not secreted, properly?, (i) Insulin, (ii) Thyroxine, (iii) Testosterone, (iv) Growth hormone., What is the role of adrenaline hormone that is, secreted and released in the blood?

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13., 14., , 15., 16., , Compare hormonal and nervous mechanism, for control and coordination., Differentiate between:, (i) Spinal nerve and cranial nerve., (ii) Dendrite and axon., (iii) Central nervous system and peripheral, nervous system., How is involuntary action different from reflex, action?, In figures (a), (b) and (c), which appears more, accurate and why?, , 1., , (i) Improper secretion of growth hormone, secreted by anterior lobe of pituitary, produces three important disorders. Name, them. Also give their cause., (ii) Posterior lobe of pituitary stores and, secretes two hormones. Name these, hormones and also give one important, function of each at these hormones., List the functions of testosterone and, estrogen., (i) Describe various parts of central nervous, system in human beings., (ii) Give three functions of brain., Define reflex arc and draw its labeled, diagram., Nervous and hormonal systems together, perform the function of control and, coordination in human beings. Justify the, statement., Name various plant hormones. Also give their, physiological effects on plant growth and, development., (i) Mention one function of each of these, hormones:, (a) Thyroxine, (b) Insulin, (c) Adrenaline, (d) Growth hormone, (e) Testosterone., (ii) Draw the diagram of section of human, brain., A person is taking cortisone hormone, (glucocorticoids from adrenal) for the, treatment of his ailment. Doctor has advised, him not to stop the medicine all of a sudden,, rather he should taper off the medicine slowly, by reducing the dosage in phases. What is the, logic behind this act?, How does control and coordination take place, in plants?, What do you mean by homeostasis? Explain, negative feedback control of a hormone with, the help of an example., , 2., 3., , 17., 18., 19., , 20., 21., 22., 23., , 24., 25., , 26., , 27., , What are meanings? What is their function?, Name the main parts of the nervous system of, grasshopper (insect)., Give reason, why :, (i) Reflex actions are also generally known as, spinal reflexes?, (ii) Nervous system and endocrine system are, often collectively known as neuroendocrine, system?, What are nastic movements? Give one, example., Describe how auxins are related with the, bending of shoots towards the source of light., Explain apical dominance. Name the hormone, that controls it., Why do the leaves of Touch me not' plant, (Mimosa pudica) droop down when touched?, Name the phenomenon involved in such a, response., Differentiate between endocrine, exocrine, and heterocrine glands., (i) Which hormone is released into blood, when its sugar level rises?, (ii) Name the organ which produces this, hormone., (iii) What is its effect on blood sugar level?, (iv) Name one digestive enzyme that this, organ secretes., (v) Give the function of this enzyme., (i) Give the full form of GH ., (ii) Name the gland that secretes it., (iii)Mention its any two functions. Name the, hormone that inhibits the secretion of GH., Name the disorder that is caused due to the, failure of secretion of GH., Taking the example of auxins and cytokinins, together, explain :, (i) a synergistic action in plants., (ii) an antagonistic action in plants., , 4., 5., , 6., , 7., , 8., , 9., 10., , Multiple Choice Question, 1., 8., 15., 22., 29., 36., 42, , A, D, B, A, D, C, , 2., 9., 16., 23., 30., 37., , B, B, D, B, D, C, , 3., 10., 17., 24., 31., 38., , C, C, A, A, A, B, , 4., 11., 18., 25., 32., 39., , B, B, A, D, B, A, , 5., 12., 19., 26., 33., 40., , A, D, A, C, B, B, , 6., 13., 20., 27., 34., 41., , C, A, A, B, A, D, , 7., 14., 21., 28., 35., 42., , D, B, A, A, A, C

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43., 50., 57., 64., 71., 78., 85., 92., 99., , D, A, D, A, C, B, C, C, C, , 44., 51., 58., 65., 72., 79., 86., 93., , D, C, B, B, A, C, C, C, , 45., 52., 59., 66., 73., 80., 87., 94., , B, A, C, A, D, A, B, B, , 46., 53., 60., 67., 74., 81., 88., 95., , C, C, D, A, B, C, B, C, , 47., 54., 61., 68., 75., 82., 89., 96., , A, D, A, D, A, D, B, D, , 48., 55., 62., 69., 76., 83., 90., 97., , D, D, C, A, C, B, A, B, , 49., 56., 63., 70., 77., 84., 91., 98., , A, C, C, D, B, D, C, C, , Fill in the Blanks, , 1., 3., 5., 7., 9., 11., 13., 15., 17., 19., , motor, axon, auditory, reflex action, hormones, plant hormones, Hormones, sensory receptors, medulla oblongata, central, canal;, cerebrospinal fluid, , 2., 4., 6., 8., 10., 12., 14., 16., 18., 20., , neurotransmitters, nastic, synapse, electrical impulses, brain; spinal cord, geotropism, Thyroxine, cranium, Sensory (afferent), , True or False, , 1. False, 3. True, 5. True, 7. False, 9. False, 11. False, 13. True, 15. False, 17. False, 19. True, , 2. False, 4. True, 6. False, 8. False, 10. True, 12. True, 14. True, 16. True, 18. False, 20. True, Assertion and Reason Type, , 1. A, 5. C, 9. C, , 2. D, 6. A, 10. A, , 3. B, 7. C, 11. B, , 4. A, 8. C, , 43