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PLUS ONE ZOOLOGY, , The Living World, FOCUS AREA NOTES, For Watching Video click the link below, , https://youtu.be/n4q3UB--dBo, • Scientific name of Man & House Fly, • Man, : Homo sapiens, • House Fly : Musca domestica, Taxonomical aids, • Taxonomical aids help to identify the species, helps to place the, organism in taxonomical hierarchy and also to store the specimen, for future use., • Taxonomical aids such as herbarium, museum, botanical Gardens,, zoological parks, keys, Flora, Manuals, Monographs etc are used for, taxonomical studies., , Herbarium, • Herbarium is a store house of collected plant specimens that are, dried, pressed and preserved on sheets., • Herbarium sheets are arranged according to universally accepted, system of classification.

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• These specimens become a store house for future use and serve as a, quick referral system in taxonomy., •, , The herbarium sheets carry a label providing information about, date and place of collection, English, local and botanical names,, collector’s name etc., , Botanical Gardens, • Botanical gardens are specialized gardens which have collections of, living plants for reference., • Plant species in these gardens are grown for identification purposes., • Each plant is labeled indicating its botanical / scientific name and, its family., •, , The famous botanical gardens are at Kew (England), Indian, Botanical Garden-Howrah (India), and at National Botanical, Research Institute (Lucknow)., , Museum, • Museums are places where plant animal specimens are preserved, for study and reference., •, , Specimens are preserved in the containers or jars in the, preservative solutions., , • Plant and animal specimens are also preserved as dry specimens., •, , Insects are preserved in insect boxes after collecting, killing and, pinning., , • Larger animals like birds and mammals are usually stuffed and, preserved., • Museums also have collections of animal skeletons., Zoological Parks, , • These are the places where wild animals are kept in protected, environments under human care.

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• This helps to learn about the behavior of animals and also their, food habits., In zoological parks, we provide a natural habitat to the animals., , •, , • These parks are commonly called zoos., , Key, • Key is a taxonomical aid used for identification of plants and, animals based on their similarities and dissimilarities., • The keys are based on the contrasting characters generally in pair, called couplet., • Each statement in a key is called a lead., • Separate taxonomic keys are required for each taxonomic category, such as family, genus and species for identification purposes., •, , Keys are generally analytical in nature.

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Alternation of Generations (Metagenesis), , Examples:, • Physalia (Portuguese man-of-war),, • Adamsia (Sea anemone),, • Pennatula (Sea-pen),, • Gorgonia (Sea-fan) and, • Meandrina (Brain coral), , Phylum – Ctenophora, Comb Plates, • The body of Ctenophores bears eight external rows of ciliated comb, plates, which help in locomotion., , Bioluminescence, • It is the property of a living organism to emit light., • It is well-marked in ctenophores

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Examples:, • Pleurobrachia and, • Ctenoplana, , Phylum – Platyhelminthes, Adaptations of Parasitic forms, • Hooks and suckers are present in the parasitic forms., • Some of them absorb nutrients from the host directly through, their body surface., Examples:, •, , Taenia (Tapeworm),, , •, , Fasciola (Liver fluke)., , Phylum – Aschelminthes, Difference between male and female worms, • Sexes are separate (dioecious), i.e., males and females are distinct., • Often females are longer than males., , Examples :, •, , Ascaris (Round Worm),, , •, , Wuchereria (Filaria worm),, , •, , Ancylostoma (Hookworm)., , Phylum – Annelida, Metamerism, • The body surface of members of Annelida is distinctly marked out, into segments or metameres (Latin, annulus : little ring) and, hence,, the phylum name Annelida and the phenomenon is metamerism.

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Examples:, •, , Pila (Apple snail),, , •, , Pinctada (Pearl oyster),, , •, , Sepia(Cuttlefish),, , •, , Loligo (Squid),, , •, , Octopus (Devil fish),, , •, , Aplysia (Sea-hare),, , •, , Dentalium (Tusk shell) and, , •, , Chaetopleura (Chiton)., , Phylum – Echinodermata, Water vascular system, • The most distinctive feature of echinoderms is the presence of water, vascular system which helps in locomotion, capture and transport of, food and respiration., , Examples:, •, , Asterias (Star fish),, , •, , Echinus (Sea urchin),, , •, , Antedon (Sea lily),, , •, , Cucumaria (Sea cucumber) and, , •, , Ophiura (Brittle star)., , Phylum – Chordata, Fundamental Characters, • Animals belonging to phylum Chordata are fundamentally, characterised by the, • presence of a notochord, a dorsal hollow nerve cord and paired, pharyngeal gill slits .

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Class – Osteichthyes, Cycloid/Ctenoid scales, •, , Skin of osteichthyes is covered with cycloid/ctenoid scales, , Significance of air bladder, • Air bladder of osteichthyes regulates buoyancy., , Example:, Hippocampus (Sea horse), , •, , Comparison between Chondrichthyes and Osteichthyes, , Class – Amphibia, Respiration of amphibians is by gills, lungs and through skin., , •, , Cloaca, • Alimentary canal, urinary and reproductive tracts of amphibians open, into a common chamber called cloaca which opens to the exterior., , Examples:, •, , Rana (Frog), , •, , Salamandra (Salamander)

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Class – Reptilia, Epidermal scales or scutes, • The body of reptiles are covered by dry and cornified skin, epidermal, scales or scutes., , Skin cast, • Snakes and lizards shed their scales as skin cast., , Class – Aves, Adaptations, • The characteristic features of Aves (birds) are the presence of feathers, • The forelimbs are modified into wings., • The hind limbs generally have scales and are modified for walking,, swimming or clasping the tree branches., •, , Endoskeleton is fully ossified (bony) and the long bones are hollow, with air cavities (pneumatic)., , • Air sacs connected to lungs supplement respiration., , Examples, •, , Corvus (Crow),, , • Columba (Pigeon),, • Psittacula (Parrot),, • Struthio(Ostrich),, • Pavo (Peacock),, • Aptenodytes (Penguin),, • Neophron (Vulture).

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Class – Mammalia, • The most unique mammalian characteristic is the presence of milk, producing glands (mammary glands) by which the young ones, are nourished., • They have two pairs of limbs, adapted for walking, running, climbing,, burrowing, swimming or flying ., • The skin of mammals is unique in possessing hair., •, , External ears or pinnae are present., , • Different types of teeth are present in the jaw., •, , Heart is four-chambered., , • They are homoiothermous., • Sexes are separate and fertilisation is internal., • They are viviparous with few exceptions and development is direct.

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TLB’S Biology Classes, , STRUCTURAL ORGANISATION IN ANIMALS, Focus Area Notes, For Video , Use the link below, https://youtu.be/dvghq4dXpK8, There are two types of epithelial tissue., , A. Simple epithelium, B. Compound epithelium, , A. SIMPLE EPITHELIUM, • Simple epithelium is composed of single layer of cells., • It functions as lining for body cavities, ducts and tubes, On the basis of structural modification of cells simple epithelium is, further divided into 3 types., , 1.Squamous epithelium, • It is made of a single thin layer of flattened cells with irregular, boundaries., •, , They are found in the walls of blood vessels and air sacs of lungs, and are involved in a functions like forming a diffusion boundary., , 2.Cuboidal epithelium, •, , It is formed of single layer of cube like cells., , •, , It is commonly found in ducts of glands and tubular parts of, nephrons in kidneys.

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TLB’S Biology Classes, •, , The main function are secretion and absorption., , •, , The epithelium of proximal convoluted tubule (PCT) of nephron in, the kidney has microvilli which help in absorption., , 3.Columnar epithelium, It is formed of a single layer of tall and slender cells., , •, , •, , Their nuclei are located at the base., , • Free surfaces may have microvilli., They are found in the lining of stomach and intestine and help in, , •, , secretion and absorption., , Ciliated epithelium, • If the columnar or cuboidal cells bear cilia on their free surface, they are called ciliated epithelium., • Their function is to move particles or mucus in a specific direction, over the epithelium., •, , They are mainly present in the inner surface of hollow organs like, bronchioles and fallopian tubes.

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TLB’S Biology Classes, , Cell junctions in epithelial tissues, • All cells in epithelium are held together with little inter cellular, material., •, , Specialized junctions provide both structural and functional links, between individual cells., , Mainly three type of cell junctions are found in epithelial cells, , 1. Tight junctions, Help to stop substances from leaking across a tissue, , 2. Adhering junctions, Perform cementing to keep neighbouring cells together., , 3. Gap junctions, Facilitate the cells to communicate with each other by connecting the, cytoplasm of adjoining cells, for rapid transfer of ions, small molecules, and sometimes big molecules., , Loose connective tissue, • These tissues have cells and fibers loosely arranged in a semi-fluid, ground substance., , Eg . Areolar tissue, Adipose tissue, Areolar tissue, • Areolar tissue is present beneath the skin., • It contains fibroblasts (cells secrete fibers),macrophages and mast, cells., , Adipose tissue, • Adipose tissue is also present beneath the skin. These tissues are, specialized to store fat.

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TLB’S Biology Classes, , Tendons – attach muscles to bones, Ligaments – attach one bone to another bone, , Muscle tissue, • Muscles play an active role in all the movements of the body., • Muscles are of three types, , 1. Skeletal muscles, 2. Smooth muscles, 3. Cardiac muscles, 1.Skeletal muscles(striated muscle), • Skeletal muscle tissue is closely attached to the skeletal bones, , 2.Smooth muscles, • The smooth muscle fibers taper at both ends and do not show, striations., • Cell junctions hold them together and they are bundled together in a, connective, tissue sheath.

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TLB’S Biology Classes, , • The wall of internal organs such as the blood vessels, stomach and, intestine contains this type of muscle tissue., • Smooth muscles are involuntary as their functioning cannot be directly, controlled., , 3.Cardiac muscle, • The muscle present only in the heart is known as cardiac muscle., • Cell junctions fuse the plasma membranes of cardiac muscle cells and, make them stick together., • Communication junctions (intercalated discs) at some fusion points, allow the cells to contract as a unit. I.e., when one cell receives a signal to, contract, its neighbours are also stimulated to contract.

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TLB’S Biology Classes, , Neural tissue, The neuroglia cells constitute the major part of the neural system which, protect and support neurons., Neuroglia makes up more than one half the volume of neural tissue in, our body., , Mouth Parts of cockroach( Biting and Chewing type), Anterior end of the head bears appendages forming biting and, chewing type of mouth parts., a labrum (upper lip),, a pair of mandibles,, a pair of maxillae and, a labium (lower lip) hypopharynx (acting as tongue)

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TLB’S Biology Classes, , Alimentary canal of Cockroach, The alimentary canal is divided into three regions:, • foregut, • midgut, • hindgut., , Fore gut consists of, • Mouth, • Pharynx, • Oesophagus, • Crop, • Gizzard or proventriculus., The entire foregut is lined by cuticle., , Crop, , •, , Oesophagus opens into a sac like structure called crop which is used, for storing of food., , Gizzard or proventriculus, • Gizzard helps in grinding the food particles.

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TLB’S Biology Classes, , • It has an outer layer of thick circular muscles and thick inner culicle, forming six highly chitinous plate called teeth., , Hepatic or Gastric caecae, , •, , A ring of 6-8 blind tubules present at the junction of foregut and, midgut are known as Hepatic or Gastric caecae., , • Its function is secretion of, , digestive juice., , Malphigian tubules, , •, , A ring of 100-150 yellow coloured, thin filamentous tubules present, at the junction of midgut and hindgut are known as Malphigian, tubules ., , •, , Their function is removal of excretory products from haemolymph., , Hind Gut, • The hindgut is broader than midgut and is differentiated into, • ileum,, • colon and, • Rectum., • The rectum opens out through anus.

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TLB’S Biology Classes, , Nervous system,  Compound eyes are present, consists about 2000 ommatidia, which, make several images of an object. This is known as mosaic vision.

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TLB’S Biology Classes, , Structural Levels of Proteins, Proteins exists at 4 structural levels, • Primary structure, • Secondary structure, • Tertiary structure, • Quaternary structure, , 1. Primary Structure:, Primary structure refers to the linear sequence of amino acids in a, protein molecule., • A protein is imagined as a line, the left end represented by the first, amino acid and the right end represented by the last amino acid., •, The first amino acid is called as N-terminal amino acid and the last, amino acid is called is C-terminal amino acid., •, , 2. Secondary Structure:, • The right handed helical, , form of proteins are known as secondary, , structure., • A protein thread does not exist throughout as an extended rigid rod., • The thread is folded in the form of a revolving staircase known as, helix., , 3.Tertiary Structure:, The polypeptide chains of protein molecules bend and fold to attain, a three dimensional shape called Tertiary structure., • The structure is helpful for many biological activities., •, , 4. Quaternary Structure:, •, , More than one polypeptide chains unite together to form the, complicated folded structure called Quaternary structure of, protein., , Eg: Human haemoglobin, •, •, , Adult human Haemoglobin has 4 polypeptide chains., Two are identical known as alpha chains and other two are also, identical known as beta chains.

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TLB’S Biology Classes, , • The alpha and beta chains folded together to form a compact, globular structure of haemoglobin, , , Peptide bonds, The chemical bond which connect amino acids are known as, peptide bond., Each peptide bond is formed by the reaction between the carboxyl group, (COOH) of one amino acid with the amino group (NH ) of next amino, 2, acid with the elimination of water (dehydration reaction), , Glycosidic bond, • In a polysaccharide individual monosaccharide are linked by, glycosidic bond formed between two carbon atoms of the adjacent, monosaccharides., , Phosphodiester bond, • In nucleic acid phosphate is attached to the sugar by an ester bond., • Phosphate is linked to sugars of two adjacent nucleotide form, Phosphodiester bond.

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TLB’S Biology Classes, , Structure of DNA, Pyrimidine bases of DNA, • cytosine ,, • thymine (in DNA), , Purine bases, • Adenine and, • guanine, Sugar in DNA, •, , The sugar present in DNA is, , Deoxy ribose, , Watson – crick model of DNA, • This model says that DNA exists as a double helix., • The two strands of polynucleotide are antiparallel i.e., run in the, opposite direction., • The back bone is formed by the sugar – phosphate – sugar chain., • The nitrogen bases interconnect the backbone., • Adenine of one strand pairs with thymine of the other strand, (A-T base pair) by two hydrogen bonds., •, , Guanine pairs with Cytosine (G-C base pair)by three hydrogen, bonds., , • One full turn of helical stair case has Ten base pairs., •, , The total length of a turn is 34A0 and the distance between two base, pairs is 3.4A0., , •, , This type of DNA is known as B-DNA

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TLB’S Biology Classes, , Factors Affecting Enzyme Activity, • The activity of an enzyme can be affected by a change in the, conditions which can alter the tertiary structure of the protein., • These include Temperature, pH, change in substrate concentration, or, binding of specific chemicals that regulate its activity., Temperature and pH, • Enzymes generally function in a narrow range of temperature and, pH., • Each enzyme shows its highest activity at a particular temperature, and pH called the optimum temperature and optimum pH., • Activity declines both below and above the optimum value., • Low temperature preserves the enzyme in a temporarily inactive, state whereas high temperature destroys enzymatic activity because, proteins are denatured by heat.

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TLB’S Biology Classes, , Concentration of Substrate, • With the increase in substrate concentration, the velocity of the, enzymatic reaction rises at first., • The reaction ultimately reaches a maximum velocity(Vmax) which, is not exceeded by any further rise in concentration of the substrate., • This is because the enzyme molecules are fewer than the substrate, molecules and after saturation of these molecules, there are no free, enzyme molecules to bind with the additional substrate molecules., , Classification and Nomenclature of Enzymes, • Enzymes have been classified into different groups based on the, type of reactions they catalyse., • Enzymes are divided into 6 classes

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TLB’S Biology Classes, , Co-Factors, • The non-protein parts associated with enzyme are called co-factors.,  The co-factors are of three types, , • prosthetic group,, • co-enzymes and, • metal ions., Prosthetic Group, • The organic compounds which are tightly bind to the apoenzyme, are called prosthetic group., •, , Eg: the prosthetic group Haem is a part of the enzyme Peroxidase, and Catalase, which catalyse the breakdown of hydrogen peroxide, to water and oxygen., , Co-Enzymes, • The organic compounds which are not firmly bound to the, apoenzyme are called co-enzymes., • Many co-enzymes are vitamins., • Eg: NAD (Nicotinamide Adenine Dinucleotide), NADP (Nicotinamide, Adenine Dinucleotide Phosphate) contains the vitamin Niacin., , Metal Ions, •  A number of enzymes require metal ions for their activity., •  Eg: Zinc is a co-factor for the proteolytic enzyme carboxy, peptidase.

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TLB’S Biology Classes, , DIGESTION AND ABSORPTION, Focus area Notes, For viewing video, click the link below, https://youtu.be/--gtiZ7-O0c, , DENTITION, • Each tooth is embedded in a socket of jaw bone., • This type of attachment is called thecodont., , •, , Most mammals have two types of teeth-milk teeth or deciduous teeth, and permanent teeth., , • This type of dentition is called diphyodont dentition., , Heterodont dentition, An adult human has 32 permanent teeth which are of four different types, (Heterodont dentition), namely,, • incisors (I),, • canine (C),, • premolars (PM) and, • molars (M)., , •, , Arrangement of teeth in each half of the upper and lower jaw in the, order I, C, PM, M is represented by a dental formula which in human is, 2123/2123., , • The hard chewing surface of the teeth, made up of enamel, helps in the, mastication of food.

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TLB’S Biology Classes, , Layers of Alimentary Canal, The wall of alimentary canal from oesophagus to rectum possesses four, layers namely, • Serosa,, • Muscularis,, • Sub-mucosa and, • Mucosa., , Serosa, , • Serosa is the outermost layer and is made up of a thin, , mesothelium (epithelium of visceral organs) with some, connective tissues., , Muscularis, • Muscularis is formed by smooth muscles usually arranged into, , an inner circular and an outer longitudinal layer., , Sub-mucosal layer, • The sub-mucosal layer is formed of loose connective tissues, containing nerves, blood and lymph vessels., • In duodenum, glands are also present in sub-mucosa., , Mucosa, , • The innermost layer lining the lumen of the alimentary canal, is the mucosa.

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TLB’S Biology Classes, , Digestion of Food, Functions of mucus and bicarbonate ions, • The mucus and bicarbonates present in the gastric juice play an, important role in lubrication and protection of the mucosal epithelium, from damage by the highly concentrated hydrochloric acid., , Inactive Enzymes of Pancreatic Juice, • The pancreatic juice contains inactive enzyme., • trypsinogen,, • Chymotrypsinogen, and, • procarboxypeptidases,, , • Trypsinogen is activated by an enzyme, enterokinase, secreted, by the intestinal mucosa into active trypsin, which in turn, activates the other enzymes in the pancreatic juice., , Functions of Goblet cells, • The intestinal mucosal epithelium has goblet cells which secrete mucus., • The secretions of the brush border cells of the mucosa along with the, secretions of the goblet cells constitute the intestinal juice or, , succus entericus.

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TLB’S Biology Classes, , • This juice contains a variety of enzymes like disaccharidases (e.g.,, maltase), dipeptidases, lipases, nucleosidases, etc., • The mucus along with the bicarbonates from the pancreas protects the, intestinal mucosa from acid as well as provide an alkaline medium (pH, 7.8) for enzymatic activities. Sub-mucosal glands (Brunner’s glands), also help in this., , DISORDERS OF DIGESTIVE SYSTEM, Jaundice, • The liver is affected, skin and eyes turn yellow due to the deposit of bile, pigments., , Vomiting, • It is the ejection of stomach contents through the mouth., • This reflex action is controlled by the vomit centre in the medulla., • A feeling of nausea precedes vomiting., Diarrhoea, • The abnormal frequency of bowel movement and increased liquidity of, the faecal discharge is known as diarrhoea., • It reduces the absorption of food., Constipation, • In constipation, the faeces are retained within the colon as the bowel, movements occur irregularly., Indigestion, • In this condition, the food is not properly digested leading to a feeling, of fullness., • The causes of indigestion are inadequate enzyme secretion, anxiety,, food poisoning, over eating, and spicy food.

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TLB’S Biology Classes, , BREATHING AND EXCHANGE OF GASES, Focus area notes, For viewing video, click the link below, https://youtu.be/LniwqXupJrg, , HUMAN RESPIRATORY SYSTEM, Pharynx, , •, , It is the common passage for food and air., , Glottis & Epiglottis, • Opening of the larynx is called glottis, • A large leaf like cartilaginous lid guards the opening of larynx (glottis), called epiglottis., • Epiglottis prevent the entry of food into the larynx., , Pleura, • Two lungs which are covered by a double layered pleura, with pleural, fluid between them., • It reduces friction on the lung surface., • The outer pleural membrane is in close contact with the thoracic lining, whereas the inner pleural membrane is in contact with the lung, surface., , Steps in Respiration, • (i) Breathing or pulmonary ventilation by which atmospheric air is, drawn in and CO2 rich alveolar air is released out., • (ii) Diffusion of gases (O2 and CO2 ) across alveolar membrane., • (iii) Transport of gases by the blood., • (iv) Diffusion of O2 and CO2 between blood and tissues., • (v) Utilisation of O2 by the cells for catabolic reactions and resultant, release of CO2.

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TLB’S Biology Classes, , MECHANISM OF BREATHING, Breathing involves two stages :, • Inspiration during which atmospheric air is drawn in and expiration, by which the alveolar air is released out., , INSPIRATION, 1. Diaphragm contracts., 2. Volume of thoracic chambers increases in anterio posterior axis., 3. External inter coastal muscles contracts., 4. The ribs and the sternum raised., 5. Volume of thoracic chamber increases in dorso ventral axis, 6. Pulmonary volume increases., 7. Intra pulmonary pressure becomes less than atmospheric pressure., 8. Air from outside move in to the lungs., , EXPIRATION, 1. Diaphragm and inter costal muscles relaxes, 2. Thoracic and pulmonary volume decreases., 3. Intra pulmonary pressure increases above the atmospheric pressure, 4. Air from lungs expelled.

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TLB’S Biology Classes, , RESPIRATORY VOLUMES AND CAPACITIES, Tidal Volume (TV):, • Volume of air inspired or expired during a normal respiration., • It is approx. 500 mL., i.e., a healthy man can inspire or expire, approximately 6000 to 8000 mL of air per minute., Residual Volume (RV):, • Volume of air remaining in the lungs even after a forcible expiration., • This averages 1100 mL to 1200 mL., , TRANSPORT OF GASES, , Transport of Oxygen, • About 97 per cent of O2 is transported by RBCs in the blood., • The remaining 3 per cent of O2 is carried in a dissolved state through, the plasma., • The red coloured pigment present in RBC is haemoglobin., •, , Haemoglobin binds with O2 in a reversible manner, , • One haemoglobin molecule binds with four O2 molecule, • In tissues oxyhaemoglobin dissociates to O2 and haemoglobin.

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TLB’S Biology Classes, , What are the factors, oxyhaemoglobin in lungs ?, , which, , favour, , the, , formation, , of, , • High PO2,, • low PCO2,, • lesser H+ concentration and, • low temperature in the alveoli help in the formation of, oxyhaemoglobin in the lung alveoli., What are the factors which, oxyhaemoglobin in tissues?, , favour, , the, , dissociation, , of, , In tissues, • low PO2,, • high PCO2,, • high H+ ion concentration and, • higher temperature favour dissociation of oxyhaemoglobin in, tissues., • Every 100 ml of oxygenated blood can deliver around 5 ml of, O2 to the tissues under normal physiological conditions., , Oxygen dissociation curve, •, , •, , •, , The binding O2 with haemoglobin is mainly related to partial, pressure of O2., If we plot the partial pressure of O 2 against percentage of, saturation of haemoglobin with O2 a sigmoid curve is, obtained., This curve is known as oxygen dissociation curve., , • This curve is highly useful in studying the effect of factors like, PCO2 ,H+ conc., temperature etc.

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TLB’S Biology Classes, , DISORDERS OF RESPIRATORY SYSTEM, ASTHMA, • Difficulty in breathing causing wheezing due to inflammation of, bronchi and bronchioles., EMPHYSEMA, • Chronic disorder in which alveolar walls are damaged due to which, respiratory surface is decreased., • One of the major causes of this is cigarette smoking., , Occupational Respiratory Disorders, • This is due to the exposure of harmful substances like fumes or dust, present in the environment where a person works., • Long exposure can give rise to inflammation leading to fibrosis, (proliferation of fibrous tissues) and thus causing serious lung damage.

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TLB’S Biology Classes, , BODY FLUIDS AND CIRCULATION, Focus Area Notes, For video use the link below, https://youtu.be/3TURYCsp6FAh, BLOOD GROUPS,  Two types of blood grouping is widely used.,  They are, , ABO type and Rh type ., , ABO grouping,  ABO grouping is based on the presence or absence of two surface, antigen A and B on the RBC and the antibodies present in the plasma.,  A group has antigen A and antibody b,  B group has antigen B and antibody a,  AB group has antigen A and B but no antibody,  O group has antibody a and b but no antigen, BLOOD GROUPS AND DONOR COMPATIBILITY,  During blood transfusion inorder to avoid clotting donor’s blood is, matched with recipient’s blood.,  Antibody a reacts with antigen A and in the same way antibody b, reacts with antigen B leading to the destruction of RBCs ., , ‘universal donors’ and ‘universal recipients’,  Group ‘O’ blood can be donated to persons with any other blood, group and hence ‘O’ group individuals are called ‘universal, donors’.

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TLB’S Biology Classes, ,  Persons with ‘AB’ group can accept blood from persons with AB as, well as the other groups of blood.,  Therefore, such persons are called ‘universal recipients’., , Rh GROUPING,  Surface of RBC contains another antigen known as Rh antigen.,  Rh antigen is first observed in Rhesus monkey , hence the name.,  Persons with Rh antigen is Rh positive and without Rh antigen is Rh, negative.,  If an Rh negative person receives blood from Rh positive one, his, blood will develop antibody against Rh antigen., ERYTHROBLASTOSIS FOETALIS,  This is an Rh incompatibility disease.,  This can be seen in Rh positive foetus which is developing in the, uterus of Rh negative lady who became pregnant in the second time.,  During the delivery of first child mixing of maternal and foetal blood, occurs .,  Then the mother begins to produce antibodies against Rh antigen in, her blood,  This Rh antigen enters in to the foetus if the lady conceives the, second child and destroy the foetal RBC .

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TLB’S Biology Classes, ,  This can be avoided by injecting anti Rh antibodies to the mother, immediately after the first child., , COAGULATION OF BLOOD,  Blood exhibits clotting or coagulation in response to an injury, inorder to prevent excessive loss of blood from the body.,  Clotting involves the conversion of soluble plasma protein fibrinogen, into an insoluble form called fibrin.,  This reaction is catalysed by the enzyme thrombin.,  Thrombin is found in the blood in an inactive form called, prothrombin,  The enzyme complex thrombokinase convert prothrombin to, thrombin through a series of reactions.,  Thromboplastin released from platelets and damaged tissues initiates, the formation of thrombokinase,  Ca2+ ions are essential for the activation and action of thrombin.

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TLB’S Biology Classes, , HUMAN CIRCULATORY SYSTEM, Pericardium,  The double walled membrane which protect the heart is pericardium,  Pericardium has a fluid in it known as pericardial fluid., , Valves in Heart,  The opening of atria to the ventricle is guarded by valves.,  Tricuspid valve guard the opening of right atrium and right ventricle.,  Bicuspid or mitral valve guard the opening of left atrium and left, ventricle.,  Semilunar valves guard the openings of pulmonary artery and aorta,  These valves allow the blood to flow in only one direction., CONDUCTING SYSTEM IN HEART, Sino –atrial node (SA Node),  This is a special type of muscle tissue present in the right upper, corner of the right atrium which initiates and maintain the rhythmic, contractile activity of the heart., Atrio – Ventricular Node (AV Node),  The mass of nodal muscle tissue seen in the lower left corner of, the right atrium close to the atrio ventricular septum is atrio, ventricular node, Purkinje fibers,  The right and left bundles from AVN branches again and give rise, to minute fibers throughout the ventricles known as purkinje, fibers., Bundle of His,  Purkinje fibres along with right and left bundles are known as, Bundle of HIS.

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TLB’S Biology Classes, , Functions of SAN,  The nodal musculature has the ability to generate action potentials, without any external stimuli, i.e., it is autoexcitable.,  The SAN can generate the maximum number of action potentials,, i.e., 70-75 min–1 , and is responsible for initiating and maintaining, the rhythmic contractile activity of the heart.,  Therefore SAN is called the pacemaker of heart, Flow chart of the path of Impulse conduction in Heart

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TLB’S Biology Classes, , CARDIAC CYCLE – SYSTOLE & DIASTOLE,  Contraction of the heart chambers is systole,  Relaxation of the heart chambers is diastole,  The contraction and subsequent relaxation of the chambers of the, heart constitute a heart beat .,  The sequential event in the heart which is cyclically repeated is called, the cardiac cycle and it constitute atrial and ventricular systole, and, diastole.,  The heart beats 72 times/mt.,  So the duration of cardiac cycle is 0.8 seconds, Atrial systole,  All the 4 chambers are in the relaxed state.,  Tricuspid and bicuspid valves are open .,  Blood from the pulmonary veins and venacava flows into the left and, right ventricles through the right and left atria.

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TLB’S Biology Classes, , Ventricular systole,  The contraction of the ventricles is ventricular systole.,  It begins when the ventricles are full of blood .,  When the ventricles begin to contract, the tricuspid and bicuspid, valves close and the deoxygenated blood is forced to enter the, pulmonary artey and oxygenated blood enter the aorta opening the, semilunar valves., Diastole,  The relaxation of heart chambers after contraction is diastole,  The atria and ventricles relax simultaneously .,  So it is known as joint diastole.,  During atrial diastole right atrium is filled with deoxygenated blood, and left atrium is filled with oxygenated blood from the lungs., Sounds of heart,  During each cardiac cycle two prominent sounds are produced which, can be heard using a stethoscope.,  The first heart sound is lub , which is associated with the closure of, the tricuspid and bicuspid valves.,  The second sound is dub, which is associated with the closure of the, semilunar valves.,  These sounds are of clinical diagnostic significance., , Electrocardiograph(ECG),  The machine used to record the electrical activity of the heart during, cardiac cycle is called electrocardiograph.,  The graph obtained from the machine is electrocardiogram,  The ECG has 3 peaks- P , QRS and T .,  The P-wave represents the electrical excitation or depolarization of, the atria.,  The QRS complex represents the depolarization of the ventricles,  The T wave represents the return of the ventricles from excited to, normal state(repolarisation).

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TLB’S Biology Classes, ,  The end of the T- wave marks the end of the systole,  The deviation from the standard shape indicates abnormality or, disease. Hence it has great significance., , Disorders of circulatory system, High Blood Pressure (Hypertension),  Normal blood pressure is 120/80 mm of Hg,  120 mm of Hg is the systolic pressure and 80 mm of Hg is the, diastolic pressure,  If the blood pressure rises to 140 / 90 , that condition is known as, hypertension,  Hypertension leads to heart diseases , damage to brain and kidney., , Atherosclerosis (coronary artery disease)(CAD),  It is an arterial disease due to the deposition of calcium , fat ,, cholesterol and fibrous tissues on the inner lining of the large and, medium sized arteries ,which make the arteries narrower., , Angina ( angina pectoris),  A symptom of acute chest pain due to the deficiency of oxygen to the, heart muscles,  It is more common in middle – aged and elderly

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TLB’S Biology Classes, ,  It occurs due to the block of blood flow.,  It may lead to heart attack., Heart failure,  This is a condition in which the heart is not pumping enough blood to, meet the needs of the body.,  It is sometimes called congestive heart failure because congestion of, the lungs is one of the main symptoms of this disease.

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TLB’S Biology Classes, , EXCRETORY PRODUCTS AND THEIR ELIMINATION, Focus Area Notes, , For watching video, click the link below, https://youtu.be/FoqyNFhqvy8, Based on the mode of nitrogen excretion there are three type of excretion., • Ammonotelism, • Ureotelism, • Uricotelism, , Ammonotelism, • The process of excretion of nitrogenous waste in the form of ammonia, is called ammonotelism., • The animals which excrete ammonia are called ammonotelic ., Ammonotelism is seen in aquatic animals. Why ?, • Ammonia is highly toxic and water soluble ., • A large amount of water is required for its elimination ., • So ammonotelism is seen in aquatic animals., , Ureotelism, • The process of excretion of nitrogenous waste in the form of urea is, called ureotelism., • The animals which excrete urea is called ureotelic ., • Urea is less toxic and highly soluble in water than ammonia., • Eg . man and other mammals ,terrestrial amphibians , marine fishes, etc., , Uricotelism, • The animals which excrete the nitrogenous waste in the form of uric, acid are called uricotelism., • Uric acid is less soluble in water and hence it does not require water for, its excretion

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TLB’S Biology Classes, , • So Uricotelism, conservation., , is, , exhibited, , by, , animals, , which, , require, , water, , Eg . reptiles , birds , insects land snails etc, , HUMAN EXCRETORY SYSTEM, , NEPHRON, • Each kidney has nearly one million tubular nephrons., • Nephrons are the structural & functional units of kidney., , Parts Nephron, 1. Bowman’s capsule, , •, , At the proximal end nephron is curved and expand inwardly to form, , double walled cup shaped structure called bowman’s capsule., 2. Glomerulus, , •, , The network of capillaries within the bowman’s capsule is glomerulus., , 3. Malpighian corpuscle, • Glomerulus along with Bowman’s capsule, is called the malpighian, body or renal corpuscle.

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TLB’S Biology Classes, , 4. Proximal convoluted tubule(PCT), • The coiled portion of nephron after the malpighian corpuscle is, proximal convoluted tubule ., 5. Afferent arteriole, • The artery through which the blood enters the glomerulus is afferent, arteriole, 6. Efferent arteriole, • The artery from which the blood leaves the glomerulus is efferent, arteriole., 7. Loop of Henle, • A hairpin shaped tubular portion in between proximal and distal, convoluted tubule is Loop of Henle., • It consists of a descending limb and an ascending limb ., 8. Distal convoluted tubule (DCT), • The highly coiled tubular portion after the ascending limb is distal, convoluted tubule., 9. Collecting duct, • The distal convoluted tubule of many nephrons open into a straight, tube called Collecting duct .

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TLB’S Biology Classes, , URINE FORMATION, • Urine is formed in the nephrons ., • It involves 3 steps, , 1. Glomerular filtration, 2. Tubular reabsorption, 3. Tubular secretion, Glomerular Filtration, • It occurs in the malpighian corpuscles., • When blood flows under high pressure through the glomerular, capillaries , water and dissolved substances of blood filter out into the, lumen of the bowman’s capsule ., • The glomerular capillary blood pressure causes filtration of blood, through 3 layers –, • the endothelium of glomerular blood vessel ,, • the epithelium of bowman’s capsule and, • a basement membrane between these two layers., • The epithelial cells of bowman’s capsule called podocytes are arranged, in an intricate manner so as to leave some minute spaces called, filtration slits or slit pores., • This fluid is known as glomerular filtrate., • The glomerular filtrate contains all the constituents of blood except, blood corpuscles and plasma proteins ., • It contains glucose , urea , creatinine , mineral salts etc. ., • Therefore it is known as ultra filtration., • The volume of glomerular filtrate formed in bowman’s capsule per unit, time is called glomerular filtration rate (GFR)., • In man GFR rate is 125ml/ minute or about 180L/ day.

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TLB’S Biology Classes, , 2.Tubular reabsorption, • Out of 180L of glomerular filtrate formed , only 1.5 L of urine is, released ., • So 99% of the filtrate is reabsorbed ., • Proximal and distal convoluted tubules , the loop of henle and, collecting duct are involved in reabsorption., • Sugar , vitamins , organic nutrients and water are reabsorbed., , 3.Tubular secretion, • It is the final step in urine formation and it involves the active secretion, of some substances from the blood into the filtrate., • Proximal and distal convoluted tubules are the main parts of tubular, secretion., • It helps in the maintenance of acid – base balance of the body., , REGULATION OF KIDNEY FUNCTION, 1. Control By Antidiuretic Hormone (ADH), 2. Control By Juxta Glomerular Apparatus (JGA), 3. Control By Atrial Natriuretic Factor (ANF), , 1. Control By Antidiuretic Hormone (ADH), • ADH is also called vasopressin ., • It is secreted by hypothalamus and released into blood by pituitary., • An excessive loss of fluid from the body can activate Osmoreceptors of, hypothalamus to release antidiuretic hormone (ADH) or vasopressin, from the neurohypophysis., • When body fluid decreases, ADH is secreted and more water is, reabsorbed in the kidney tubules ., • Deficiency of ADH leads to the impermeability of tubules and excretion, of large amont of hypotonic urine ., • This diseases is Diabetes insipidus.

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TLB’S Biology Classes, , 2. Control By Juxta Glomerular Apparatus (JGA), • When the blood pressure in the afferent arteriole decreases JGA, releases an enzyme known as renin into the blood ., • Renin converts a plasma protein , angiotensinogen to a hormone, known as angiotensin II., • Angiotensin II , constricts the arterioles and blood pressure is increased, and there by GFR., • Angiotensin II also activates the adrenal cortex to release Aldosterone., • Aldosterone causes reabsorption of Na+ and water from the distal, parts of the tubule., • This also leads to an increase in blood pressure and GFR., • This complex mechanism is generally known as the Renin-Angiotensin, mechanism.

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TLB’S Biology Classes, , 3. Control By Atrial Natriuretic Factor (ANF), • An increase in blood flow to the atria of the heart can cause the release, of Atrial Natriuretic Factor (ANF)., • ANF can cause vasodilation (dilation of blood vessels) and thereby, decrease the blood pressure., • ANF mechanism, therefore, acts as a check on the renin-angiotensin, mechanism., , DISORDERS OF THE EXCRETORY SYSTEM, UREMIA, • The accumulation of urea in blood due to the malfunctioning of kidneys, is uremia., GLOMERULONEPHRITIS, • Inflammation of glomeruli of kidney

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TLB’S Biology Classes, , LOCOMOTION AND MOVEMENT, , Focus Area Notes, For watching video, click the link below, https://youtu.be/VAfeklmIPDs

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TLB’S Biology Classes, , SKELETAL SYSTEM, •, , Ribs, • There are 12 pairs of ribs., • Each rib is a thin flat bone connected dorsally to the vertebral column, and ventrally to the sternum., • It has two articulation surfaces on its dorsal end and is hence called, bicephalic.

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TLB’S Biology Classes, , • First seven pairs of ribs are called true ribs., • Dorsally, they are attached to the thoracic vertebrae and ventrally, connected to the sternum with the help of hyaline cartilage., •, , The 8, , th, , ,9, , th, , and 10, , th, , pairs of ribs do not articulate directly with the, , sternum but join the seventh rib with the help of hyaline cartilage., • These are called vertebrochondral (false) ribs., th, th, • Last 2 pairs (11 and 12 ) of ribs are not connected ventrally and are, therefore, called floating ribs., • Thoracic vertebrae, ribs and sternum together form the rib cage

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TLB’S Biology Classes, , JOINTS, •, , The place of articulation between two or more bones or between a, bone and a cartilage is known as joints., , • 3 types of joints are there, , 1. Fibrous joints, • Fibrous joints do not allow any movement., • This type of joint is shown by the flat skull bones which fuse end-to-end, with the help of dense fibrous connective tissues in the form of sutures,, to form the cranium., , 2. Cartilaginous joints, • In cartilaginous joints, the bones involved are joined together with the, help of cartilages., • The joint between the adjacent vertebrae in the vertebral column is of, this pattern and it permits limited movements., , 3. Synovial joints, • Synovial joints are characterised by the presence of a fluid filled, synovial cavity between the articulating surfaces of the two bones., • Such an arrangement allows considerable movement., • These joints help in locomotion and many other movements., , • Ball and socket joint, (between humerus and pectoral girdle(Shoulder joint) femur and pelvic, girdle (Hip joint)),, , • hinge joint (knee joint, elbow joint),

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TLB’S Biology Classes, , • pivot joint (between atlas and axis),, • Gliding joint (between the carpals), • saddle joint (between carpal and metacarpal of thumb) are, some examples., , DISORDERS OF MUSCULAR AND SKELETAL SYSTEM, Arthritis, , •, , inflammation of joints, , Osteoporosis, , • Age related disorder characterized by decreased bone mass, and increased chances of fractures., • Decreased levels of oestrogen is a common cause, , Gout, • Inflammation of joints due to accumulation of uric acid crystals

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TLB’S Biology Classes, , NEURAL CONTROL AND COORDINATION, Focus Area Notes, For watching video, click the link below, https://youtu.be/bfweNzrYbZA, NEURONS,  The neural system of all animals is composed of highly specialized, cells called neurons.,  Neurons are the structural and functional unit of nervous system., , Structure of neurons,  Neurons are formed of mainly 3 parts –, ,  cell body,,  dendrites and,  axon.,  The cell body contains cytoplasm with typical cell organelles., , Nissl’s granules,  These are the granular bodies present in the cytoplasm of neurons., , Dendrites,  Short fibers which branch repeatedly and project out of the cell body, are known as dendrites., , Axon,  This is the long fiber in the neuron., , Schwan cells,  The special type of cells which cover the axon., , Synaptic knob,  The bulb like structure present at the end of dendrites.

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TLB’S Biology Classes, ,  These, , knobs, , contain, , synaptic, , vesicles,, , which, , contains, , neurotransmitters., Based on the number of axon and dendrites, the neurons are classified, into 3 types., , 1. Multipolar Neurons, • These are neurons with one axon and two or more dendrites., Eg . Neurons in the cerebral cortex., , 2. Bipolar Neurons, • Neurons with one axon and one dendrite, Eg. Neurons in the retina of eye., 3. Unipolar Neurons, • Cell body with one axon only., •, , These types of neurons are found only in the embryonic stage., , Myelinated Nerve Fibre,  Some neurons have a covering of myelin sheath around the schwan, cells of axon are known as myelinated nerve fibers ., Eg. Nerve fibers of the spinal and cranial nerves ., , Non – myelinated nerve fibre,  Nerve fibers without myelin sheath around the axon ., Eg. Nerve fibers in the somatic and autonomous systems ., , Nodes of Ranvier,  The gap between two adjacent myelin sheath is called nodes of, Ranvier .

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TLB’S Biology Classes, , TRANSMISSION OF NERVE IMPULSES, SYNAPSE,  Synapse is the junction between two neurons .,  A nerve impulse is transmitted from one neuron to another, through synapse .,  The neuron which bring impulse to synapse is the presynaptic, , neuron, , and the neuron which receive impulse is the post, , synaptic neuron .,  The gap in the synapse is the synaptic cleft ., Two types of synapse are present –

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TLB’S Biology Classes, , • Electrical synapse and, • Chemical synapse ., 1.Electrical Synapse,  Here , the membranes of pre – and post synaptic neurons are very, close .,  Electrical current can flow directly from one neuron into the other, across these synapses .,  Impulse conduction in electrical synapse is always faster than, chemical synapse ., , 2. Chemical Synapse,  Here , the membranes of the pre – and post synaptic neurons are, separated by fluid filled space called synaptic cleft .,  In chemical synapses , impulse conduction occurs through chemical, substances in the synapse called neurotransmitters .,  The axon terminals contain vesicles filled with neurotransmitters .,  When an impulse (action potential) arrives at the axon terminal , it, stimulates the synaptic vesicles to break .,  The synaptic vesicles break to release the neurotransmitters in the, synaptic cleft .,  The neurotransmitters bind to the specific receptors of the post –, synaptic neurons .,  This binding opens ion channels and through these channels action, potential reach the post synaptic neuron.

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TLB’S Biology Classes, , FOREBRAIN,  The forebrain consists of, ,  cerebrum ,,  thalamus and,  hypothalamus, CEREBRUM,  Cerebrum is the major part of the brain .,  Cerebrum is divided longitudinally into two halves , termed as the left, and right cerebral hemispheres, , Corpus callosum,  The group of nerve fibers which connect the two cerebral, hemispheres are called corpus callosum ., HYPOTHALAMUS,  Hypothalamus lies at the base of thalamus .,  It controls body temperature , urge for eating and drinking etc.

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TLB’S Biology Classes, ,  The neurosecretory cells of hypothalamus secrete oxytocin and, vasopressin, , MIDBRAIN,  Dorsal portion of the midbrain consists four round swelling called, , corpora quadrigemina, HINDBRAIN,  The hindbrain consists of, ,  pons ,,  cerebellum and,  medulla,  Pons consists of nerve tracts that interconnect different regions of, the brain .,  Medulla is connected to the spinal cord .,  Medulla oblongata controls respiration , cardiovascular reflexes and, gastric secretions ., REFLEX ACTION AND REFLEX ARC,  Reflex action is the involuntary response towards a nervous, stimulation without the involvement of entire part of the central, nervous system .,  The reflex pathway consists of –, , 1. afferent neuron (receptor) –, which receives the stimulus from a sensory organ and, transmits it to the spinal cord via dorsal nerve root ., , 2. efferent neuron (effector or excitor)which carries signals from the spinal cord to the effetor organ.

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TLB’S Biology Classes, , 3. interneuron which connect afferent and efferent neuron .,  The stimulus and response of the reflex pathway together known as, , reflex arc.,  Knee jerk reflex is an example for reflex action ., , EYE,  Eyes are located in the sockets of the skull called orbits .,  The eye ball is composed of three layers –, 1. Sclera – external layer , composed of dense connective tissue ., 2. Choroid – middle layer , contains many blood vessels and, looks bluish in colour ., 3. Retina - inner layer , contains photosensitive cells ., , Cornea,  The anterior portion of sclera is transparent called cornea ., Ciliary body

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TLB’S Biology Classes, ,  The anterior part of the choroid layer is thick and called ciliary, body ., Iris,  The ciliary body continues forward to form a pigmented and opaque, structure called the iris ., Lens, • The eye ball contains a transparent crystalline lens which is held in, place by ligaments attached to the ciliary body., Pupil,  The aperture in the iris is called pupil .,  The diameter of the pupil is regulated by the muscles fibers of iris ., Retinal Layer,  The inner layer is the retina and it contains three layers of neural, cells – from inside to outside –, , • ganglion cells,, • bipolar cells and, • photoreceptor cells., There are two types of photoreceptor cells, namely, rods and cones, Rods,  Rods contain the light sensitive pigment rhodopsin or visual purple, , which contains a derivative of vitamin A.,  Rods help in twilight vision or scotopic vision., Cones,  Cones, , help in day light vision or, , vision .,  They contain the pigment iodopsin ., , photopic vision, , and colour

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TLB’S Biology Classes, ,  Three type of cone cells which respond to red , green and blue lights, are present . Different colours are produced by the combination of, these colours .,  Equal stimulation of cones produce white colour, Blind spot,  In the retina , at the point where the optic nerve leave the eye , rod, and cone cells are absent . This spot is called blind spot ., Macula lutea & Fovea, , •, , Lateral to the blind spot, there is a yellowish pigmented spot called, macula lutea with a central pit called the fovea., , •, , The fovea is a thinned-out portion of the retina where only the cones, are densely packed., , • It is the point of keenest vision., Aqueous chamber,  The space between the cornea and the lens is called the aqueous, chamber and it contains a thin watery fluid called aqueous humor ., Vitreous chamber,  The space between the lens and the retina is called the vitreous, chamber and is filled with a transparent gel called vitreous humor.

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TLB’S Biology Classes, , THE EAR,  Ear is the organ for hearing and balancing .,  Ear has three regions – outer ear , middle ear and the inner ear ., , Outer ear,  Outer ear consists of the,  pinna,,  external auditory meatus (ear canal) , and,  tympanic membrane (ear drum) .,  Pinna collects the sound and ear canal leads the sound waves to ear, drum,  The minute hairs , and wax secreted by the sebaceous glands in the, ear canal prevent the entry of dust and foreign bodies into the ear ., , Middle ear,  Middle ear contains three bones – malleus , incus and stapes, attached one after the other .,  Malleus is attached to the tympanic membrane .,  Stapes is attached to the oval window of the cochlea .,  Eustachian tube connect the middle ear cavity with the pharynx .,  It helps in equalizing the pressure on either side of the ear drum ., Inner ear,  Inner ear is formed of membranous labyrinth and bony labyrinth .,  The bony labyrinth is filled with a fluid called perilymph.,  The membranous labyrinth lies in this perilymph and it is formed of, two portions called vestibular apparatus and cochlea .

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TLB’S Biology Classes, , Vestibular apparatus,  It is composed of three semicircular canals and the otolith organ, consisting of the saccule and utricle.,  Each semicircular canal is swollen at the base called ampulla .,  Ampulla contains a projecting ridge called crista ampullaris which, has hair cells .,  The saccule and the utricle contain projecting ridge called macula .,  The crista and macula are the specific receptors responsible for the, maintenance of balance of the body and posture ., Cochlea,  The coiled portion of the membranous labyrinth is called cochlea .,  The cochlea has three longitudinal chambers –,  upper scala vestibuli ,,  middle scala media and the,  lower scala tympani .

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TLB’S Biology Classes, ,  Scala vestibuli is separated by scala media by a membrane called, Reissner’s membrane .,  Scala media is separated from scala tympani by Basilar membrane .,  Scala vestibuli, , and, , scala tympani are filled with perilymph and, , scala media is filled with endolymph .,  Organ of Corti, , is the structure located on the basilar membrane, , which acts as auditory receptors .,  Organ of corti contains sensory hair cells arranged in rows .,  The basal end of the hair cells is in close contact with the auditory, nerve fibre .,  The apical part of the hair cells posses a large number of process, called stereo cilia .,  Above the rows of the hair cells a thin elastic membrane called, tectorial membrane is present .

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TLB’S Biology Classes, , CHEMICAL COORDINATION AND INTEGRATION, , Focus area notes, For watching video ,use the link below, , https://youtu.be/tBnfTXjcnpw, HYPOTHALAMUS, Releasing hormones,  The hormones secreted by hypothalamus which stimulate secretion of, pituitary hormones are called releasing hormones., Eg. Gonadotropin Releasing Hormone (GnRH), , Inhibiting hormones,  The hormone secreted by the hypothalamus which inhibit secretions, pituitary hormones are called inhibiting hormones,  Eg. Somatostatin from the hypothalamus inhibits the release of, growth hormone from the pituitary ., PIUITARY GLAND, Hormones of anterior pituitary (pars distalis), 1. Growth hormone (GH), , Gigantism,  Over secretion of growth hormone stimulates abnormal growth of the, body leading to gigantism., Dwarfism,  Low secretion of growth hormone results in stunted growth known as, pituitary dwarfism ., , TLB’S Biology Classes

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TLB’S Biology Classes, , Acromegaly, Excess secretion of growth hormone in adults especially in middle age can, result in severe disfigurement (especially of the face) called Acromegaly., Thyroid stimulating hormone (TSH),  TSH stimulates the synthesis and secretion of thyroid hormones from the, thyroid gland., Function of follicle stimulating hormone (FSH) in males,  In males FSH stimulates spermatogenesis ., Function of follicle stimulating hormone (FSH) in females,  In females FSH stimulates growth and development of ovarian follicles., Function of oxytosin,  Oxytocin stimulates contraction of uterine muscles during child birth, and initiates ejection of milk from mammary gland ., Function of vasopressin (ADH)-antidiuretic hormone.,  It stimulates reabsorption of water and electrolytes from the kidney, tubules and thereby reduces loss of water through urine .(diuresis).,  Defect in synthesis or release of ADH results in a diminished ability of, the kidney to conserve water leading to water loss and dehydration.,  This condition is known as Diabetes Insipidus., , The Pineal Gland, • Pineal gland secretes a hormone called melatonin., •, , Melatonin plays a very important role in the regulation of a 24-hour, (diurnal) rhythm of our body., , TLB’S Biology Classes

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TLB’S Biology Classes, , • It helps in maintaining the normal rhythms of sleep-wake cycle, body, temperature., • Melatonin also influences metabolism, pigmentation, the menstrual, cycle as well as our defense capability., , Thyroid Gland, Functions of Thyroid hormones,  Thyroid hormones play an important role in the regulation of the, basal metabolic rate.,  support the process of red blood cell formation.,  control the metabolism of carbohydrates, proteins and fats.,  Control water and electrolyte balance., , Parathyroid Gland, , , , Four parathyroid glands are present on the back side of the thyroid, gland, one pair each in the two lobes of the thyroid gland., ,  The parathyroid glands secrete a peptide hormone called,  parathyroid hormone (PTH)., , , , Parathyroid hormone (PTH) increases the Ca2+ levels in the blood, (hypercalcemic hormone )., ,  PTH increases blood calcium level by,  bone resorption, , , , reabsorption of Ca2+ by the renal tubules and, , , , increases Ca2+ absorption from the digested food., , TLB’S Biology Classes

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TLB’S Biology Classes, , Adrenal Gland, , •, , Adrenaline and noradrenaline are rapidly secreted in response to, stress of any kind and during emergency situations and are called, emergency hormones or hormones of Fight or Flight., , Pancreas,  Pancreas is a composite gland which acts as both exocrine and, endocrine gland.,  The endocrine pancreas consists of ‘Islets of Langerhans’.,  The two main types of cells in the Islet of Langerhans are called, α -cells and β -cells.,  The α-cells secrete a hormone called glucagon,,  while the β -cells secrete insulin., Role of Insulin,  Insulin decreases blood glucose level by various methods .,  Hence insulin is a hypoglycemic hormone .,  Insulin stimulates conversion of glucose to glycogen known as, glycogenisis,  Insulin promotes synthesis of fat from glucose .,  Enhance cellular glucose uptake and utilization ., , TLB’S Biology Classes

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TLB’S Biology Classes, , Diabetes mellitus,  Prolonged hyperglycemia leads to a complex disorder called diabetes, mellitus which is associated with loss of glucose through urine and, formation of harmful compounds known as ketone bodies.,  Diabetic patients are successfully treated with insulin therapy., Role of Glucagon,  Glucagon is a peptide hormone, and plays an important role in, maintaining the normal blood glucose levels.,  Glucagon acts mainly on the liver cells (hepatocytes) and stimulates, glycogenolysis resulting in an increased blood sugar (hyperglycemia).,  In addition, this hormone stimulates the process of gluconeogenesis, which also contributes to hyperglycemia.,  Glucagon reduces the cellular glucose uptake and utilisation., , , Thus, glucagon is a hyperglycemic hormone., Testis, ,  A pair of testis is present in the scrotal sac (outside abdomen) of male, individuals.,  The leydig cells or interstitial cells of testis produce group of hormones, called androgens mainly testosterones., , TLB’S Biology Classes

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TLB’S Biology Classes, , Functions of Androgens,  Androgens regulate the development, maturation and functions of the, male accessory sex organs like, , epididymis, vas deferens, seminal, , vesicles, prostate gland, urethra etc.,  These hormones stimulate muscular growth, growth of facial and, axillary hair, aggressiveness, low pitch of voice etc.,  Androgens, , play, , a, , major, , stimulatory, , role, , in, , the, , process, , of, , spermatogenesis (formation of spermatozoa)., , Ovary,  Females have a pair of ovaries located in the abdomen.,  Ovary is the primary female sex organ which produces one ovum during, each menstrual cycle.,  Ovary produces two groups of steroid hormones called estrogen and, progesterone.,  After ovulation, the ruptured follicle is converted to a structure called, corpus luteum, which secretes mainly progesterone.,  Progesterone supports pregnancy.,  Progesterone also acts on the mammary glands and stimulates the, formation of alveoli and milk secretion., , TLB’S Biology Classes

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TLB’S Biology Classes, , Functions of Estrogens,  Estrogens produce wide ranging actions such as stimulation of growth, and activities of female secondary sex organs, development of growing, ovarian follicles, appearance of female secondary sex characters,, mammary gland development etc., , Hormones Of Heart , Kidney And Gastrointestinal Tract, Atrial Natriuretic factor (ANF), • It is the hormone secreted by atrial wall of heart ., • When blood pressure increases ANF is secreted and which causes the, dilation of blood vessels .This reduces the blood pressure ., , Juxtaglomerular cells of kidney, , •, , The juxtaglomerular cells of kidney produce a peptide hormone called, erythropoietin which stimulates erythropoiesis (formation of RBC)., , TLB’S Biology Classes