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CHAPTER â 7, , Control and Coordination, Living organisms respond and react to various stimuli like heat, light, cold, touch,, pressure etc. Plants and animals both respond to stimuli but in different manner., Example : withdrawl of hand on touching a hot object., Control and Coordination in Animals, It is brought about in all animals with the help of two main systems, a) Nervous System, , b), , Endocrine System, , Nervous System :, Functions, i), , To receive the information from environment, , ii) To receive the information from various, body parts. (Stimuli fi, Response), iii) To act accordingly through muscles and glands., Stimulus : Any change in environment or within that bring about the reaction eg:, touching a hot plate., Response : The reaction of our body to these changes. eg. withdrawal of our hand, How do we detect that we are touching a hot object?, Receptors : Are specialised tips of some nerve cells that detect the information, from the environment., Receptors, are, Sense Organs, Inner, Ear, , Photo receptors, Eyes, , Skin, , Olfactory, Receptor, (Nose), , Gustatory, Receptor, (Tongue), , Hearing/, Balance of, the body, , Visual, Stimulus, , Pain, Touch, Heat, , Smell, Detection, , Taste, Detection, , 63, , X-Science
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Neuron : Structural and functional unit of nervous system., Neuron (3 main parts), I, , II, , III, , Dendrite, , Cell body, and Axon, , Synapse, , Information is, acquired, , Information, travels as an, electrical impulse, , Part where, electrical signal, is converted into, chemical message, for onward transmission, to next neuron, by release of neurotransmitters, , Nucleus, Nerve, ending, , Dendrite, Axon, , Cellpody, , Structure of neuron, Fig. 7.1 (a) P 115, , Synapse : The point of contact between the terminal branches of axon of one, neuron with the dendrite of another neuron is called synapse., Reflex Action, A quick, sudden, immediate response of the body to the certain stimuli that, involves Spinal cord. eg. (not brain) withdrawal of hand, knee jerk etc., Reflex arc : The pathway through which impulses pass is called reflex arc., , 64, , X-Science
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Stimulus, âº, eg. Heat, , Sensory Nerves, , RECEPTOR, ORGAN, (SKIN), , Spinal Cord, Response, âº, eg. Withdrawal, of, Hand, , EFFECTOR, ORGAN, (MUSCLE), , Motor Nerves, , Refer to diagram Fig 7.2 Reflex arc, Response, Responses are of three main types, Voluntary : Controlled by fore brain, eg. Talking, Writing, Involuntary : Controlled by mid and hind brain, eg. Heart beat, vomiting, regulation of heartbeat, Reflex action : controlled by spinal cord, eg. Withdrawl of hand on touching a hot object., Human Nervous System, Central Nervous, System, , Peripheral, Nervous, System, , Autonomic, Nervous, System, , (CNS, , (PNS), , (ANS), , Brain, , Spinal, Cord., Fore Brain, Mid Brain, , Cranial, Nerves, , Spinal, Nerves, , Arise from, the brain, , Arise from, Spinal Card, , Sympathetic, Nervous, System, , Para, Sympathetic, Nervous, System, , Hind Brain, , 65, , X-Science
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Human Brain, Human brain has three major parts or regions, a) Forebrain b) Mid Brain c) Hind Brain, FOREBRAIN, Most complex/specialized part of the brain is CEREBRUM, FUNCTIONS :, 1. Thinking part of the brain, 2. Control the voluntary actions., 3. Store information (Memory), 4. Centre associated with HUNGER, 5. Receives sensory impulses from various body parts and integrates it, Mid Brain :, HYPOTHALAMUS : Chemical co-ordination, PITUITARY GLAND : Secretes hormones, Hind Brain :, CEREBELLUM i) Controls posture and balance, ii) Control precision of voluntary actions, MEDULLA, , Controls involuntary actions, eg. blood pressure, salivation, vomiting, , PONS, , Involuntary action, regulation of respiration, , Fig 7.3 Human Brain, 66, , X-Science
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PROTECTION OF BRAIN AND SPINAL CORD, Brain :, Spinal Cord :, , Brain is protected by a fluid filled balloon which acts as shock, absorber and enclosed in cranium (Brain Box), Spinal Cord is enclosed in Vertebral column., , Coordination between Nervous and Muscular Tissue, Information, [collected by, Nervous tissue], (Sensory Nerve), , Central, Nervous, System, [CNS], , Information, Processed, by, [CNS], Decesion, made, [by CNS], , Action, Muscle shorten, Contraction, [Muscle cell], , (Motor Nerves), Message, Muscles, [Change in shape, and arrangement, of proteins], , Passed to, muscles, , Coordination in Plants, Movement in Plants, Movement dependent, on growth, , Movement independent, of growth, [immediate response, to stimulus], eg. dropping of leaves, of Touch-me-not, plant on touching it, , Tropic movements, [directional movements, in response to stimulus], Phototropism, , Geotropism, , Chemotropism, , Hydrotropism, , Movement, towards light, , Movement, towards gravity, , Movement, towards Chemicals/, growth of pollen, tube towards avule, , Movement, towards /, water, , 67, , X-Science
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Plant hormones :, Are chemical compounds which help to coordinate growth, development and, responses to the environment., Plant hormones : Main plant hormones are :, a) Auxin : [Synthesized at shoot tip], Function : â Helps in growth, Phototropism : more growth of cells towards light., b) Gibberellin : Helps in the growth of the stem, c) Cytokinins : Promotes cell division, d) Abscisic acid : Inhibits growth, cause witting of leaves., (Stress hormone), , Hormones in Animals, Hormones : These are the chemical messengers secreted in very small amounts by, specialised tissues called ductless glands. They act on target tissues/organs usually, away from their source., Endocrine System helps in control and coordination through chemical compounds, called HORMONES, , 68, , X-Science
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S., No., , Hormone, , Endocrine, Gland, , Location, , Functions, , 1., , Thyroxine, , Thyroid, , Neck/, Throat, region, , Regulation of metabolism, of carbohydrates, fats, and proteins., , 2., , Growth, hormone, , Pituitary, , Mid, , Regulates growth and, development., , 3., , Adrenaline, , Adrenal, , Above, both, kidneys, , Regulation (increasing), of blood pressure, heart, heat, carbohydrate, metabolism (during, emergency), , Testosterone, in Males, , Testes, , Changes associated, with puberty, (Sexual maturity), , estrogen, , Ovaries, , Genital/, lower, abdomen, area, , Insulin, , Pancreas, , Below, stomach, , Reduces and regulates, blood sugar level, , 4., SEX, Hormone, , 5., , {, , G, O, N, A, D, S, , IODISED SALT IS NECESSARY BECAUSE :, Iodine mineral is essential part of thyronine hormone so it is important that we, must consume iodised salt as in turn it is essential for thyroid gland as it controls, carbohydrate, proteins and fat metabolism for best balance of growth deficiency of, iodine might cause disease called goitre, Diabetes :, Cause : It is due to deficiency of Insulin hormone secreted by Pancreas that is, responsible to lower/control the blood sugar levels., Treatment : Patients have to internally administer injections of insulin hormone, fi, which helps in regulating blood-sugar level., Feedback Mechanism, fi, makes sure that hormones should be secreted in precise quantities and at right, time, which is regulated by feedback mechanism., , 69, , X-Science
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SWITCH OFF, Feedback sent, , Sugar level in the blood rises, Detected by cells of Pancreas, Synthesis insulin, Blood sugar level falls, , (like a float in watertank), Stop secreting more, insulin, , EXERCISE, (Question Bank), Very Short Answers (1 Mark), 1., , Where is auxin synthesized in plants?, , 2., , Which gland is known as Master gland?, , 3., , Name the hormone that regulates blood sugar level., , 4., , What is synapse., , 5., , What are tropic movements? Give one examples, , 6., , Define hormones, , 7., , Which hormone has inhibiting effect on growth of plants, , 8., , What is phototropism?, , 9., , What are the components of central Nervous System., , 10., , What happens at synapse between two neurons., , Short Answers (2 Marks), 1., , Draw diagram of neuron and label cell body, dendrites and axon., , 2., , What is reflex arc? Explain with the help of a flow-chart., , 3., , Mention one function of each of the following, i), , Cerebellum, , ii), , Pons., , 4., , What is the cause of diabetes? How it can be controlled., , 5., , Why it is advisable to use iodised salt., , 70, , X-Science
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6., , What are the different receptors present in our body? What are their, functions., , 7., , What are plant hormones? Name a plant hormone that promotes growth in, plants., , 8., , What are sensory and motor neurons? Write their functions., , Long Answers (5 Marks), 1., , 2., , What are hormones (in animals) List four characteristics of hormones. Name, the hormone required for the following., i), , Development of moustache and beard in human male, , ii), , Lowering of blood glucose., , Mention the functions of, a), , Fore brain, , b), , Mid brain, , c), , Hind brain, , 71, , X-Science