Page 2 :
This reading content version herein developed by www.gneet.comfor, personal/academic use only. any use for commercial purpose will lead, to infringement of the of the rights of www.gneet.com, , Disclaimer, The information contained in this pdf is for general information, purposes only. The information is provided by Gore Coaching Classes, and while we endeavour to keep the information up to date and correct,, We make no representations or warranties of any kind, express or, implied, about the completeness, accuracy, reliability, suitability or, availability with respect to the pdf or the information, products,, services, or related graphics contained in the pdf for any purpose. Any, reliance you place on such information is therefore strictly at your own, risk., In no event will we be liable for any loss or damage including without, limitation, indirect or consequential loss or damage, or any loss or, damage whatsoever arising from loss of data or profits arise out of, or in, connection with, the use of this pdf, , email about error to, , [email protected] for corrections, , www.gneet.com

Page 3 :
www. gneet.com, , TOPIC INDEX, 1.0 Types of glands, 2.0 Hormones, 2.01 Properties of hormones, 2.02 Classification of hormones, 2.03Role of hormones in homeostasis, 3.0 Mechanism of hormone action, 3.1 Hormone Feedback system, 3.02 Peptide hormone action, 3.03 Steroid hormone action, 4.0 Pineal gland, 5.0 Hypothalamus Gland, 6.0 Pituitary glands, 6.01 Hormones secreted by adenohypophysis, 6.02 Hormones secreted by neurohypophysis, 6.03 Pituitary disorders, 7.0 Thyroid gland, 8.0 Parathyroid gland, 8.01 Disorders of pyrathyroid gland, 9.0 Thymus gland, 10.0 Adrenal glands, 10.1 Adrenal cortex, 10.2 Adrenal medulla, 11.0 Hormones disorders, 12. Kidney, 13.0 Pancreas, 14.0 Gonads, 14.01Male sex hormones, , www.gneet.comP a g e | 1

Page 4 :
www. gneet.com, , 14.01.01 Eunuchoidism, 15.0 Female sex hormones, 16.0, , Puberty related endocrine abnormalities, , 16.1 Hypogonadism, 16.2 Precocious puberty, 16.3 Gynaecomastia, 17.0 other organs which secrete hormones, 17.1 Heart, 17.2 Salivary glands, 17.3 Gastrointestinal mucosa, 18.0 Hormones which always remains in tissue fluid, 19.0 Distinguish, 20.0 Important feedback mechanism, , •, , Body functions are controlled and regulated by two neuro, endocrine system, nervous and endocrine., , •, , Nervous regulation is very fast, taking only milliseconds, and limited to only a part of target. Hormonal regulation is, a bit slower but influence all the sensitive cells of target, tissue., , •, , Nervous system is also known to stimulate endocrine, system., , •, , Endocrine system is a system of isolated glands that pour, their secretions directly into venous blood or lymph for, passage to different body organs in order to control their, functioning, metabolism, cell permeability growth,, differentiation and stress conditions. Endocrine system, comprises endocrine glands and their hormones. The, branch of science that is connected with the study of, , www.gneet.comP a g e | 2

Page 5 :
www. gneet.com, , endocrine glands, hormones and their effects is known as, endocrinology., •, , “Thomas Addison” is known as father of Endocrinology, , 1.0Types of glands, •, , Glands is an organ, tissue or cell that secretes a chemical, from performing a particular functions., , (i), , Exocrine glands: It is a gland that pours its, secretion on the surface or into a particular region by, means of ducts for performing a metabolic activity., Example, sebaceous glands, sweat gland, salivary, glands, gastric glands, intestinal gland., , (ii), , Endocrine glands: It is an isolated gland which, secretes informational molecules or hormones that are, poured into venous blood or lymph for reaching the, target organ because the gland is not connected with, the target organ by any duct. Endocrine gland is, therefore, also called duct less glands., , (iii), , Heterocrine gland: It is a gland that has both, exocrine and endocrine region, the former pouring, their secretion through ducts and latter pouring their, secretion directly into blood., , (iv), , Mixed organs: It is an organ which has both an, endocrine activity and a metabolic or cytogenic, activity. Example; gonads, , •, , Target cell/ organ: It is organ/ cell on which the product of, another system acts. In hormonal system there can be, three types of targets- primary, secondary and final. For, example, the primary target of TRH ( Thyrotropin, Releasing Hormone) is anterior pituitary which releases, , www.gneet.comP a g e | 3

Page 6 :
www. gneet.com, , TSH( Thyrotropin or Thyroid Stimulating Hormone) that, has thyroid as secondary target. The secondary target or, thyroid releases thyroxine which controls metabolic, relations of different body cells ( final target)., , 2.0Hormones, •, , Hormones are secreted in minute quantities and are, transported through blood to different parts of the body or, target organs., , •, , When some hormones work together to control a process,, this is called synergism e.g. FSH and LH., , •, , When two hormones work against each other to control a, process, this is called antagonism eg. Insulin and glucagon, and calcitonin and parathormone., , •, , Hormones receptors are found either exposed on the, surface of the cell or within the cell, depending on the type, of hormone. In very basic terms, binding of hormone to, receptors triggers a cascade of reactions within the cell, that affects function., , •, , The secretion of hormones is regulated by feed back, mechanisms, , •, , Synthesis and release of some hormones is regulated by, nerves and the hormones may also influence nerve, activities., , 2.01Properties of hormones, (i), , They have low molecular weight., , (ii), , They are soluble in water and blood., , (iii), , They have no cumulative effect., , www.gneet.comP a g e | 4

Page 7 :
www. gneet.com, , (iv), , They can act in very low concentration., , (v), , They are non-antigenic., , (vi), , They are organic catalysts., , (vii), , They may act slowly or quickly., , (viii), , Hormone controlled reactions are not reversible., , (ix), , Their excess or deficiency leads to disorders., , (x), , They do not provide energy or building materials, , (xi), , Hormones are produced in inactive form called, prohormones. Eg. Proinsulin Insulin, , (xii), , It is also called messenger because it has effect at a, site different from the site it is synthesized., , (xiii), , Hormones, unlike enzymes do not catalyze any, reaction., , 2.02 Classification of hormones, (i), , Amino acid derivative hormones, The hormones epinephrine ( adrenaline),, norepinephrine ( noradrenaline) and thyroxine are, derived from amino acid tyrosine., , (ii), , Peptide hormones, The hormones oxytocin and vasopressin are composed, of peptides., , (iii), , Protein hormones, The somatotropic, thyrotropic and gonadotropic, hormones, insulin, glucagon, parathormone, human, chorionic gonadotropin, human chorionic, somatomammotropin ( HCS) andrelaxin are made up, of proteins., , (iv), , Steroid hormones, , www.gneet.comP a g e | 5

Page 8 :
www. gneet.com, , The hormones secreted by the adrenal cortex, testes, and ovaries are composed of steroids. Placental, estradiol and progesterone are also steroid hormones., , 2.03 Role of hormones in homeostasis, •, , Homeostasis means keeping the internal chemical, environment of the body constant. Hormones help, maintain homeostasis by these integrated action and, feedback control, , •.The regulation of the amounts of water and minerals in, the body. This is known as osmoregulation. This happens, primarily in the kidneys., , www.gneet.comP a g e | 6

Page 9 :
www. gneet.com, , • The removal of metabolic waste. This is known as, excretion. This is done by the excretory organs such as the, kidneys and lungs., • The regulation of body temperature. This is mainly done, by the skin., • The regulation of blood glucose level. This is mainly done, by the liver and the insulin and glucagon secreted by the, pancreas in the body, , 3.0 Mechanism of hormone action, •, , All hormones produce their specific effects on the target, tissues /cells by binding to the specific proteins called as, hormone receptors. These receptors are located on target, tissues only. There are basically two types of receptors, present in target tissues. These are:, , 1., , Membrane bound receptors, , 2., , Intra cellular receptors, , •, , The hormone receptors present on the cell membrane of, the target cells are called membrane – bound receptors., , •, , The receptors present inside the target cell are called, intracellular receptors. The binding of hormone to its, receptors leads to the formation of hormone –receptor, complex. The formation of this complex leads to some, biochemical changes in the target tissue. The target tissue, metabolism and the physiological functions are regulated, by the hormones., , 3.1 Hormone Feedback system, Negative feedback control, , www.gneet.comP a g e | 7

Page 10 :
www. gneet.com, , •In this, synthesis of hormonal slows or halts when its, level in the blood rises above normal. Eg. Blood – glucose, homeostasis. Secretion of hormone may be under the, negative feedback control of a metabolite., •For instance, increase in blood-glucose level on eating a, carbohydrate-rich meal, stimulates pancreas to secrete, insulin. Insulin stimulates the target cells to take up, glucose, which is utilized in cell respiration or is stored as, glycogen. This lowers the blood-glucose level to normal., •With the fall in blood-glucose level, insulin secretion, decreases., Positive feedback control, •In the positive feedback control an accumulating, biochemical increases its own production., •For example, uterine contraction at the onset of labour, stimulates the release of the hormone, oxytocin, which, intensifies uterine contractions., •The contraction further stimulate the production of, oxytocin. The cycle of increase stops suddenly after the, birth of the baby., , www.gneet.comP a g e | 8

Page 11 :
www. gneet.com, , 3.02Peptide hormone action, The hormones that are derivatives of amino acids,, , -, , polypeptides or proteins are formed of large molecules are, called peptide hormones. These being insoluble in lipids, cannot enter the target cell., These act at the surface of target cell as primary, , -, , messengers and bind to the cell surface receptor forming, the hormone receptor complex. This mechanism was, discovered by Nobel Prize winner EW Sutheland in 1950. It, involves following steps:, (i), , Hormone called first messenger attaches to the cell, surface receptors proteinon the outer surface of, plasma membrane of the target cell, forming a, hormone receptor complex., , (ii), , These complex activates the enzyme adenyl-cyclase, , www.gneet.comP a g e | 9

Page 12 :
www. gneet.com, , (iii), , Adenylcyclasecatalyses the conversion of ATD to cyclic, AMP(Cyclic adenosine monophosphate or cAMP) on, the inner surface of plasma membrane., , (iv), , cAMP serves as the ‘second messenger’ or intercellular, hormonal mediator delivering information inside the, target cells. This activates appropriate cellular enzyme, by cascade effect. This induces the cell machinery to, perform its specialized function., , (v), , Ca2+ may be involved along with cAMP., , (vi), , cAMP has a very short existence. It is rapidly, degraded by the cAMPphosphodiesterase., , -, , Water soluble hormones, such as amines, peptides, proteins, and glycoproteins exert their control through cyclic AMP., These are quick acting hormones and produce immediate, effect., , 3.03Steroid hormone action, -, , Steroid hormones and thyroid hormones do not bind to the, cell surfaces receptors. Being lipid soluble, these are able to, enter the cells and their nuclei and influence the gene, action., , -, , The hormone binds the receptors forming a hormone –, receptors complex. It binds to the transcription factors that, in turn bind to DNA and particular gene is activated and, transcribed. Their transcription leads to the synthesis of a, specific protein to influence the metabolism of recipient cell., , -, , Thus, the peptide hormones activate existing enzymes in, the cell, while steroid hormones bring about the synthesis, , www.gneet.comP a g e | 10

Page 13 :
www. gneet.com, , of new enzymes. Steroid hormones act slowly than peptides, but have a more sustained effect on metabolism, , 4.0 Pineal gland, •, , It is a stalked small rounded gland named so after its, resemblance with pine cone. Pineal gland is found behind, the anterior choroid plexus on the epithalamus. It has a, variable size. Weight is about 150 mg. The gland is richly, vascularised. Unlike lower animals, human pineal gland is, devoid of light sensitive cells. The gland is neurosecretory, transducer and functions as biological clock, calcification, occurs in middle age. It has pineal and glial cells. The, gland secretes two biogenic amine hormones., (i), , Serotinin: Also by disintegrating blood cells., Constricts ( vasoconstriction) blood vessels at a, place of injury., , (ii), , Melatonin: The hormone develops pale skin colour, in amphibians. Its release is governed by diurnal, , www.gneet.comP a g e | 11

Page 15 :
www. gneet.com, , Stimulates secretion of gonadotropins by adenohypophysis, which are of two types, FSH and LH., 4., , Somatotropin Releasing Hormone or Growth Hormone, Releasing Hormone ( SRH or GHRH), Stimulates production of growth hormone or, somatotrophic hormone by anterior pituitary., , 5., , Somatostatin or Growth Hormone Inhibiting Hormone (, GHIH), It inhibits adenohypophysis to secrete growth hormone., , 6., , Prolactin Releasing Hormone ( PRH), The anterior pituitary is stimulated to secrete prolactin., , 7., , Prolactin Inhibiting Hormone (PIH), The hypothalamic hormone stops synthesis of PRH by, anterior pituitary. Hormone prolactin is under predominant, inhibitory control through neurotransmitter dopamine, produced by tubero-infundibular neurons., , 8., , Melanocyte Stimulating Hormone Releasing Hormone (, mSH – RH), The releasing hormone induces intermediate pituitary to, secrete mSH, , 9., , Melanocyte Stimulating Hormone Inhibiting Hormone (, mSH – IH), The inhibiting hormone stops synthesis of mSH., , 6.0 Pituitary glands, •, , The pituitary or master gland acts as a regulating unit of, the activity of most of the other endocrine glands. It is the, most protected gland and lies in a bony cavity called as, hypophysial fossa or shell turcica of besiphenoid bone. This, gland is attached to hypothalamus by infundibulum., , www.gneet.comP a g e | 13

Page 16 :
www. gneet.com, , •, , The gland consists of two parts: adenohypophysis and, neurohypophysis., , 6.01 Hormones secreted by adenohypophysis, -, , The adenohypophysis is formed of two lobes i.e. anterior, and intermediate lobe. These both lobes are formed by, embryonic buccal cavity ( Rathke’s pouch)., Adenohypophysis contains three types of cells. These are, basophils acidophils, chromophils., a), , Growth Hormone or Somatotropin Hormone ( GH or, STH), i), , It stimulates body growth, protein and fat, and carbohydrate metabolism, , ii), , Hyposecretion of this hormone causes, dwarfism during the skeletal growth period., , iii), , Hypersecretion of this hormone during the, period of skeletal growth causes gigantism, characterized by excessive growth of bones,, with the enlargement of internal organs as, well., , iv), , Hypersecretion in adulthood causes, acromegaly. Here, the bones becomes, abnormally thick due to ossification of, periosteum and thickening of soft tissues as, well., , b), , FSH or Follicle Stimulating Hormone., i), , It is produced by the basophilic cells, along, with galactose mannose etc., , ii), , Function: In females  growth of ovarian, follicles up to ovulation, , www.gneet.comP a g e | 14

Page 17 :
www. gneet.com, , In males  Development of seminiferous, tuble and maintenance of spermatogenesis., c), , LutenizingHormone or interstitial cell stimulating, hormone ( LH or ICSH), i), , It is produced by basophilic cells. The, hormone stimulates the testis to secrete the, male sex hormones, testosterone and the, corpus luteum in ovaries to secrete female, sex hormones called progesterone., , d), , Prolactin, It is produced by acidophilc cells. This hormone, stimulates lactation ( milk production) and has a, direct effect on the breasts immediately after, parturition., , e), , Adrenocorticotropic Hormone, i), , It is secreted by the corticotropic cells of, anterior pituitary., , ii), , It stimulates the flow of blood to the adrenal, cortex, increases the concentration of, cholesterol and steroids within the gland and, increases the output of steroid hormones,, especially cortisol., , iii), , Hyposecretion causes acute psoriasis and, dermatitis ( the diseases of skin), , iv), , Its hypersecretion causes cushing’s disease, characterized by obesity, skin pigmentation, increases, excessive hair, demineralization of, bone and loss of sexual function., , f), , Thyroid stimulating hormone or TSH, , www.gneet.comP a g e | 15

Page 18 :
www. gneet.com, , It is secreted by special basophilic cells. The hormone, promotes growth and function of thyroid gland. It, secretion is stimulated by a hypothalamic thyrotropin, release factor (TRF), g), , Lipotropin Hormone, It is in the form of a complex with I, II and βLipotropins. It stimulates fatty acid liberation from, adipose tissue. Hyposecretion causes obesity and, hypersecretion causes thickness., , 6.02 Hormones secreted by neurohypophysis, •, , The neurohypophysis is formed by the posterior lobe of, pituitary gland. This lobe is developed from the, diencephalon of brain. It is a part, developed from, hypothalam and remains connected to it. Its cells are, called pituicytes., , •, , These are called supraoptic and paraventicular nuclei. The, hormones of nerohypophysis are transported from, hypothalamus to the gland via specialized portal system, called hypophysial portal system. This lobe secretes two, hormones. Which are synthesized in hypothalamus., a), , Oxytocin, A peptide hormone, initiates vigorous uterine, constrictions in females at the time of child birth, milk, secretion by mammary glands, contraction of smooth, muscles and stimulates adenohypophysis to secrete, prolactin., , b), , Vasopressin or ADH ( Antidiuretic hormone), i), , Increases reabsorption of water in kidneys, resulting in the decrease in the rate of urine, , www.gneet.comP a g e | 16

Page 19 :
www. gneet.com, , production. Its other function include, contraction of arterioles, capillaries., ii), , It reduces heart rate and helps in micturition, as well. Hyposecretion of this hormone, causes diabetes insipidus. Water balance is, distributed unless fluid intake is greatly, increased to compensate for excess loss., , 6.03 Pituitary disorders, a), , Gigantism, It is caused by excess of growth hormone from early age., It is characterized by large and well proportioned body., , b), , Simmond’s disease, It is caused due to the atrophy or degeneration of anterior, lobe of pituitary gland. In this disease, the skin of face, becomes dry and wrinkled and shows premature ageing., , 7.0 Thyroid gland, •, , Thyroid gland ( largest endocrine gland) is present in the, neck between the trachea and larynx. It is bilobed with a, connecting isthmus., , •, , The microscopic structure of the thyroid gland shows, thyroid follicles composed of cubical epithelium and filled, with a homogenous material called colloid. Small amount, of loose connective tissue forms stroma of thegland., Besides containing blood capillaries, the stroma contains, small clusters of specialized parafollicular cells or ‘c’ cells., , •, , Thyroid hormones are produced by the secretory cells, lining the follicle and stored in the colloid until needed. So, , www.gneet.comP a g e | 17

Page 20 :
www. gneet.com, , each follicle accumulates a storage form of the circulating, thyroid hormone- 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 thyroidal hormone., Bothe 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., , •, , Thyroid hormones, (i), , Increases the metabolic rate of the body and, enhance heat production and maintain BMR (, basal metabolic rate), , (ii), , Promote growth of body tissues and mental, faculties., , (iii), •, , Stimulates body differentiation., , The deficiency of thyroid hormone secretion(, hypothyroidism) during infancy causes cretinism and, myxoedema ina adults., , •, , Symptoms of cretinism includes slow body growth and, mental development, low heart rate blood pressure and, body temperature, pot belly pigeon chest and protruding, tongue., , •, , Symptoms of myxoedema or Gull’s disease includes puffy, appearance, lack of alertness, intelligence and initiative,, slow heart beat, low body temperature and reproductive, failure., , •, , Simple goiter ( Iodine deficiency goiter is the enlargement, of thyroid gland accompanied with cretinism or, , www.gneet.comP a g e | 18

Page 21 :
www. gneet.com, , myxoedema. It is caused due to dietary deficiency of, iodine., •, , 21st October is celebrated as Iodine Deficiency Disorder, Day, , •, , Exophthalmic goiter or Grave’s disease is caused due to, over secretion of thyroid hormones. It is an autoimmune, disease in which the person produces antibodies that, mimic the action of TSH but are not regulated by normal, negative feedback control. Its symptoms includes, protrusion of eye balls, loss of weight, rise in body, temperature, rapid heartbeat, nervousness, tremor and, tastelessness., , •, , Hashimoto’s disease- In this disease all aspects of thyroid, hormone are impaired. It is an autoimmune disease in, which the thyroid gland is destroyed by autoimmunity., , •, , Thyroid gland also secretes non-iodinized calcium lowering, hormone call calcitonin or thyrocalcitonin from, parafollicular cells lying scattered in between the thyroid, follicles., , •, , Calcitonin is hypocalcemic and hypophosphatemic peptide, hormone of parafollicular or c-cells of extra-follicular part, of thyroid. It checks excess plasma Ca2+ and phosphate by, decreasing mobilization from bones and prevention of reabsorption in nephrons. The hormone has an opposite, effect to parathormone produced by parathyroid., Deficiency of calcitonin results in osteoporosis or loss of, bone density, , www.gneet.comP a g e | 19

Page 22 :
www. gneet.com, , 8.0 Parathyroid gland, •, , Parathyroid gland is present as four small pouches, two of, each are embedded in the posterior surface of each lobe of, thyroid gland. The gland is developed as epithelial buds, from third and fourth pairs of pharyngeal pouches. The, hormone secreted by parathyroid gland is parathormone or, collip’s hormone., , •, , It is a linear polypeptide with about 84 amino acids and, molecular weight of 9500 Daltons., , •, , The two types of cells present in parathyroid gland are, (i), , Oxyphil cells or Chief cells or principal cells, These cells contain prominent Golgi apparatus,, endoplasmic reticulum and secretory granules., They are involved in the synthesis and secretion, of parathormones., , (ii), , eosinophils, , www.gneet.comP a g e | 20

Page 23 :
www. gneet.com, , These cells contain oxyphil granules and large, number of mitochondria in cytoplasm. Their, function is unknown., •, , Parathormone (PTH) acts directly on bone to increases, bone reabsorption and mobilize Ca2+ ions in the blood. It is, a hypercalcemic and hypophosphetemic hormone., , 8.01 Disorders of pyrathyroid gland, (a) Hyperparathyroidism, Excess secretion of parathormone, usually by benign, tumours of all the gland, causes reabsorption of calcium, from bones, raising the blood calcium level., The effects may be formation of renal calculi complicated, by pyelonephritis and renal complicated by pyelonephritis, and renal failure, muscle weakness, general fatigue,, calcification of soft tissue, osteoporosis., (b) Hypoparathyroidism, Parathormone deficiency causes an abnormally low level of, ionized calcium in the blood. This reduces absorption of, calcium from the small intestine and reabsorprtion from, bones and glomerular filtrate lead to tetany, In tetany, there are very strong painful spasms of skeletal, muscles, causing characteristics bending inwards of the, hands forearms and feet., , www.gneet.comP a g e | 21

Page 24 :
www. gneet.com, , 9.0 Thymus gland, •, , The thymus gland is located in the upper part of the thorax, near the heart. It is a soft, pinkish, bilobed mass of, lymphoid tissue. It is a prominent gland at the time of, birth but it gradually atrophies in the adult., , •, , Hassall’s corpuscles are spherical or oval bodies present in, thymus. They are phagocytic in function., , •, , Thymus secretes a hormone named thymosin which, stimulates the development of and differentiation of Tcells, increasing resistance to infections. It also hastens, attainment of sexual maturity., , 10.0 Adrenal glands, •, , There are two adrenal glands, situated on the upper side, of each kidney enclosed within the renal fascia. They are, about 4cm long and 3cm thick. Internally, the gland is, differentiated into cortical and medullary tissues. The, gland was discovered by Eustachius and its endocrine, nature was suggested by WB Canon. It has two parts, adrenal cortex and adrenal medulla., , www.gneet.comP a g e | 22

Page 25 :
www. gneet.com, , 10.1 Adrenal cortex, •, , The adrenal cortex produces three groups of hormones, from cholesterol. They are collectively called, adrenocorticoids., These are given below, , (a) Glucocorticoids, -, , Cortisol and corticosterone are the main glucocorticoids., They are essential for life. Their secretion is stimulated by, Adrenocorticotrophic hormone from the anterior pituitary, and by stress., , -, , Glucocorticoids have widespread effects on body system., The main functions include the regulation of carbohydrate, metabolism promotion of the formation and storage of, glycogen and promotion of sodium and water reabsorption, from the renal tubules. They are released during allergic, reactions., , -, , They secreted by zonafasiculata, middle zone of adrenal, cortex. It consists of cells arranged in long, straight, columns., (b) Mineralcorticoids, Aldosterone is the main mineralocorticoid. It is secreted by, zonaglomerulosa, outer zone that constitutes about 15%, of the gland and has closely packed cells arranged in, spherical clusters and arched columns., , -, , Its functions are associated with maintenance of the, electrolyte balance in the body., , -, , The amount of aldosterone produced is influenced by the, sodium level in blood. If there is a fall in the sodium blood, , www.gneet.comP a g e | 23

Page 26 :
www. gneet.com, , level, more aldosterone is secreted and more sodium is, reabsorbed., (c) Sexcorticoids ( androgen), Zonareticularis is the inner zone and consists of cells, , -, , arranged in branching cords which secrete sexcorticoids., They are associated with deposition of protein in muscles, , -, , and retention of nitrogen., These hormones are secreted as DHEA (, , -, , Dehydroxyepiandrosterone). Which is a precursor of both, testeosterone and oestrogens., Regions of Adrenal cortex, , 10.2 Adrenal medulla, •, , The adrenal medulla is completely surrounded by the, cortex. It is an outgrowth of tissue from the same source, as the nervous system and its functions are closely allied, to those of the sympathetic part of the autonomic nervous, system., , •, , It is stimulated by its extensive sympathetic nerve supply, to produce adrenaline or epinephrine and noradrenaline or, norepinephrine in the ratio of 1:4. These are commonly, called as catecholamines., , (a) Adrenaline : It is associated with potentiating the, conditions needed for fight or flight., , www.gneet.comP a g e | 24

Page 27 :
www. gneet.com, , When the body is under stress, homeostasis is disturbed., , -, , The immediate response is sometimes described as, preparing for fight or flight, These hormones increasesalertness, pubillary dilation,, , -, , sweating etc. Both these hormones increases heart beat,, strength of heat contraction and rate of respiration., (b) Nor-adrenaline: This is the postganglionic chemical, transmitter of the sympathetic nervous system. The main, function of nor-adrenaline is the maintenance of blood, pressure by causing general vasoconstriction, except of, the coronary arteries., , 11.0 Hormones disorders, (a) Hypersecretion of glucocorticoids, Hyper secretion of cortisol ( cushing’s syndrome ) has a, , -, , wide variety of effects but they may not all be present at, the same time. These include., •, , Painful adiposity of the face ( moon face), neck and trunk, , •, , Excess protein catabolism, causing thinning of subcutaneous tissue and muscle, wasting, especially of the, limbs., , •, , Suppression of growth hormone, causing arrest of growth, in children., , •, , Osteoporosis and kyphosis, if vertebral bodies are involved, , •, , Susceptibility to infection due to reduced febrile response,, depressed immune response and phagocytosis, impaired, migration of phagocytes., , •, , Insomnia, excitability, euphoria, psychotic depression., , •, , Hypertension menstrual disturbances, peptic ulceration, , (b) Hyposecretion of glucocorticoids, , www.gneet.comP a g e | 25

Page 28 :
www. gneet.com, , Inadequate secretion of cortisol causes diminished, gluconeogenesis, low blood glucose, muscle weakness and, pallor., (c) Hypersecretion of mineralocorticoids, Excess aldosterone (conn’s syndrome) affects kidney, function, causing, •, , Excessive reabsorption of sodium chloride and water, causing hypertension, , •, , Excessive excretion of potassium causing hypokalemia,, which leads to cardiac arrhythmia and muscle weakness., , (d) Hyposecretion of mineralocorticoids, Hypoaldosteronism results in failure of kidneys to regulate, sodium, potassium and water excretion, leading to, -, , Blood sodium deficiency and potassium excess, , -, , Dehydration, low blood volume and low blood pressure, •, , Addison’s disease is due to the hyposecretion of all adrenal, cortex hormones. There is electrolyte upset with low, plasma Na+ through increased urinary elimination and high, plasma K+, reduced blood volume, lower blood pressure,, marked anaemia, hypoglycaemia, great muscular, weakness, nausea, vomiting, diarrhoea and bronze, pigmentation., , (e) Hypersecretion of sexcorticoids, •, , Virilism is due to excessive secretion of sex corticoids, caused by adrenal tumour results in appearance of male, secondary characters in females like male voice, beard, moustaches, stoppage of menstruation and growth of, clitoris., , •, , Hirsutism is presence of facial and excess body hair in, females due to adrenal virilism., , www.gneet.comP a g e | 26

Page 29 :
www. gneet.com, , 12. Kidney, The kidneys produce hormones that affect the function of other, organs. For example, a hormone produced by the kidneys, stimulates red blood cell production. Other hormones produced by, the kidneys help regulate blood pressure and control calcium, metabolism., •, , The kidneys secrete three hormones: rennin,, 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, speparating 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, corten to secrete aldosterone and enhances water and, sodium reabsorption from nephrons. These factors also, elevate blood pressure., , •, , 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, , www.gneet.comP a g e | 27

Page 30 :
www. gneet.com, , •, , Calcitriol is the active form of vitamin cholecalciferol( D3)., It promotes absorption of Ca+2 and phosphrous in the, small intestine and accelerates bone formation., , 13.0 Pancreas, •, , The pancreas lies inferior to the stomach in a bend of the, duodenum. It is both an exocrine and an endocrine gland., , •, , Pancreas has group of cells called islets of Langerhans., These produce endocrine secretions. Four kinds of cells, have been identified in the islets, , -, , Alpha cells ( about 15%) produce glucagon., , -, , Beta cells (about 65%) produce insulin., , -, , Delta cells or D-cells ( about 5%) produce somastostatin., , -, , F cells: Pancreatic polypeptide cells (15%) produce, pancreatic polypeptide., •, , Glucagon stimulates the liver to convert stored glycogen, into glucose in the blood. Glucagon is controlled by, feedback in accordance with the level of glucose in the, blood. When the blood sugar rises, the secretion of, glucagon is suppressed and when it drops the secretion of, glucagon is stimulated. Glucagon is also called an ‘antiinsulin’ hormone., , •, , Insulin is antagonistic to glucagon. Insulin decreases the, level of glucose in the blood. It acts by increasing the rate, at which glucose out of the blood and into the cells and by, stimulating muscle cells to take up sugar from the blood, and convert it to glycogen., , •, , Like glucagon, insulin is primarily regulated by feedback, from the blood glucose concentration., , www.gneet.comP a g e | 28

Page 31 :
www. gneet.com, , •, , When the blood sugar level drops, the secretion of insulin, is suppressed. When the blood sugar level increases, the, secretion of insulin is stimulated., , •, , It promotes protein synthesis in tissue from amino acids, and reduces catabolism of proteins. It is an anabolic, hormone. It increases the synthesis of fat in the adipose, tissue from fatty acids and reduces the breakdown and, oxidation of fat., , •, , 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., , •, , The most common endocrine disorder of the pancreas is, the diabetes mellitus ( hyperglycemia), now recognized to, exist in two forms – insulin dependent and non insulin, dependent., , •, , The insulin dependent diabetes mellitus ( IDDM) is caused, by a failure of the Beta cells to produce adequate amounts, of insulin while the non-insulin dependent diabetes mellitus, ( NIDDM) appears to involve failure of insulin to facilitate, the movement of glucose into the cells., , •, , In both disorders the blood glucose concentration is, elevated above the normal range., , •, , Some of the glucose is excreted in the urine and water, follows the glucose, causing excessive urination and, dehydration of body tissues. The causes excessive thirst (, polydipsia). The cells are unable to utilize their proteins for, it. The person becomes very weak. Degradation of fats, increases, producing ketone bodies ( ketosis). Blood, cholesterol level rises., , www.gneet.comP a g e | 29

Page 32 :
www. gneet.com, , •, , Hypoglycemia occurs when the blood glucose level falls, below normally. Symptoms of hypoglycemia include, weakness, profuse sweating irritability, confusion,, unconsciousness and convulsions., , 14.0 Gonads, •, , Gonads are the sex glands, the ovaries and the testis., They produce ova and sperm respectively but also secrete, hormones., , 14.01Male sex hormones, -, , Male sex hormones or androgens are produced by testis., They are secreted by Leydig cells or interstitial cells found, , www.gneet.comP a g e | 30

Page 33 :
www. gneet.com, , in the connective tissue around seminiferous tubules., Androgens are steroid hormones produced under control of, ICSH ( LH) of pituitary gland with maximum activity at, puberty. Two common androgens are testosterone and, androsterone. Dihydrosterone is the active form of, testosterone., -, , Testosterone is first produced during foetal growth under, the influence of chorionic gonadotropin of placenta. There is, a spurt of testosterone production at the age of 10-13 years, when puberty begins. Testosterone production declines, after the age of 50 years. At the time of puberty, testosterone causes development of male secondary sex, organs external / accessory male sex characters, growth of, body tissue, broadening of shoulders, growth of muscles,, higher metabolism, increased sebaceous gland activity,, normal skin and formation of sperms through, spermatogenesis is mainly due to FSH. Development of, external genitalia in the male foetus is under the control of, testosterone produced by testes. Deficient androgen, secretion causes eunuchoidism, , 14.01.01 Eunuchoidism, -, , Eunuchoidism is a hormonal disorder due to non-secretion, of testosterone in a genetically male individual. The, secondary male sex organs are under developed and nonfunctional. The accessory male character fails to develop., Spermatozoa are not formed. Castration is artificial removal, of testes. Secondary male characters do not differentiate., Castrated human males are called eunuchs., , www.gneet.comP a g e | 31

Page 34 :
www. gneet.com, , 15.0 Female sex hormones, They belong to both steroid and protein categories. The, , -, , hormones are secreted by growing graafian/ ovarian,, corpus luteum and placenta., 1., , Estrogens, They are steroid hormones secreted by growing ovarian, follicles under instructions from anterior pituitary through, FSH. Estrogens include estradiol, estriol and estrone., Estradiol is the principal estrogen. Its maximum, concentration is found at the time of puberty. Later it, shows cyclic rise and fall during menstrual cycle. During, pregnancy estradiol is secreted by placenta. At puberty the, hormone is required for development of female secondary, sex organs, external / accessory female sex characters,, body contour and onset of menstrual cycle. Later on the, hormone helps in maintaining the traits and organs in, reproductive tract. During menstrual cycle, estrogen, released from growth ovarian follicle inhibits FSH secretion, and stimulates LH secretion from pituitary increasing blood, supply to uterine epithelium., , 2., , Progesterone, It is a steroid hormone secreted by corpus luteum under, the influence of LH of anterior pituitary in the second half, of menstrual cycle and hCG of placenta during pregnancy., The placenta also secretes the hormone. Routinely, progesterone causes temporary changes in endometrial, lining of uterus for receiving egg. During pregnancy it, helps in attaching embryo to uterine wall development of, placenta, maintenance of pregnancy and growth of, , www.gneet.comP a g e | 32

Page 35 :
www. gneet.com, , secretory alveoli in mammary glands. Progesterone checks, ovulation. Hyposecretion results in abortion and, misconception., 3., , Relaxin, The proteinaceous hormone is secreted by corpus luteum, towards the close of gestation period for loosening of, pelvic ligaments. Softening dilating and relaxing of uterus, for decreasing discomfort of carriage and easy child birth., , 4., , Human Chorionic Gonadotropin ( hCG), The proteinaceous hormone is secreted by placenta for, maintaining corpus lutoum,hCG is urine is an indication of, pregnancy., , 5., , Human placental Lactogenic hormone (HPL), The hormone produced by placenta prepares the, mammary glands to secrete milk., , 6., , Inhibin / Actin, Hormones produced by corpus luteum, placenta and testes, that inhibits or activates gonadotrophic activity of pituitary, gland and hypophysis., , 16.0 Puberty related endocrine abnormalities, 16.1Hypogonadism, -, , Defect or injury to hypothalamus, pituitary testes or, ovaries. In male hypogonadism, there is deficient, production of testosterone due to hypofunction of Leyding, cells or deficient formation of sperms on account of, hypofunction of sertoli cells. Both the defects may be, present. Male musculature and male secondary sexual, characteristics do not develop. In female hypogonadism, , www.gneet.comP a g e | 33

Page 36 :
www. gneet.com, , there is deficient secretion of estrogen, little development of, secondary sexual characters of females and nondevelopment of reproductive cycles., , 16.2Precocious puberty, -, , It is early maturation of primary sex organs. Ovary before, the age of 11 years and testes before the age of 12 years., Sexual pseudoprecosity in boys occurs due to excess, formation of testosterone as there is tumour growth in, testes or adrenals. It results in early enlargement of pensis,, development of pubic and axillary hair, faster body growth,, masculinisation and then stunting . Similarly, sexual, pseudoprecosity in girls results from excessive production of, estrogen due to tumours in ovaries / adrenals. Breast and, pubic hair develop early but ovarian cycle does not occur., , 16.3Gynaecomastia, Normally-developing pubertal males may be at risk for, gynecomastia that is part of the normal developmental process., Normal male infants also may have gynecomastia. Gynecomastia, results from an imbalance in hormone levels in which levels of, estrogen (female hormones) are increased relative to levels of, androgens (male hormones)., -, , It is the development of breast tissue in males due to, (i), , Perturbation of estrogen to androgens ratio., , (ii), , Temporary increase in circulating estrogen during, neonatal period and during puberty., , (iii), , Decreased testosterone in later life, , www.gneet.comP a g e | 34

Page 37 :
www. gneet.com, , 17.0 other organs which secrete hormones, 17.1Heart, It produces a peptide hormone atrial natriuretic factor (, , -, , ANF) in case of hypertension. The hormone inhibits renin (, in kidneys) and ADH secretion ( in pituitary), , 17.2 Salivary glands, The glands produce proteinaceous hormone parotine, , -, , required for calcification of teeth., , 17.3 Gastrointestinal mucosa, 1., , Gastrin, It is produced by pyloric mucosa and duodenum ( small, quantity by γ-cells in pancreas) in response to presence of, food in stomach. Stimulus is provided by vagus nerve., Gastrin stimulates secretion of gastric juices and churning, movements of stomach. Hypersecretion produces gastric, ulcers and other gastric problems., , 2., , Motilin, It is secreted by duodenum in response to food and, acidity. Motilin controls motility of stomach and intestine, , 3., , Secretin, Entry of HCl in duodenum stimulates secretion of secretin, from duodenal mucosa. The hormone stimulates secretion, of water and bicarbonate in bile and pancreatic juice. It, inhibits stomach movements and secretion of gastric juice., Secretion was the first hormone to be isolated., , www.gneet.comP a g e | 35

Page 38 :
www. gneet.com, , 4., , Enterogastrone, It is believed to be produced by duodenum in response to, chyme. Enterogastrone stops digestive activity in stomach., , 5., , Cholecystokinin, It is produced by duodenum and jejunum in response to, presence of food. Cholecystokinin stimulates the flow of, pancreatic enzymes and contraction of gall bladder., , 6., , Pancreazymin, The hormone is believed to be secreted by duodenal, mucosa and required for the flow of pancreatic juice. Both, cholecystokinin and pancreazymin are now believed to be, one structure., , 7., , Enterocrinin, The hormone secreted by duodenal mucosa stimulates, crypts of Lieberkuhan for secretion of succus or intestinal, juice., , 8., , Duocrinin, Intestinal hormone that stimulates secretion of mucus and, HCO3 from Brunner’s gland, , 9., , Villikinin, Intestinal hormone that stimulates movements of, intestinal villi, , 10. Gastric Inhibitory Peptide ( GIP), It is secreted by mucosa in the upper part of small, intestine in response to fat and protein in, chyme,monosaccharides also have a stimulating effect., GIP inhibits gastric mobility and secretion for slowing down, of passage of food. It stimulates insulin secretion., , www.gneet.comP a g e | 36

Page 39 :
www. gneet.com, , 18.0 Hormones which always remains in, tissue fluid, Never reach blood stream but remain in ECF, 1., , Neurohormones : Secreted by nodesof axons of nerve, cells, Acetylcholine and Norephrine are the main, neurohormone. Acetylcholine causes muscles to contract,, activates pain responses and regulates endocrine and REM, sleep functions., , 2., , Prostaglandin: Called local hormones. They are fatty acid,, Many types, Kidney, gonads, seminal vesicle, thymus,, brain organ and cells secrete these hormone in EC., Function in the contraction and relaxation of smooth, muscle, the dilation and constriction of blood vessels,, control of blood pressure, and modulation of inflammation., , 3., , Kinins : Called as “First aid hormone”, reducesblood, pressure by expanding blood vessels. Secreted at the time, of chemical change in ECF, , 4., , Pheromones or Ectohormones: effect the other animal’s, behavior and mode of life of same species. , are volatile, andtravel through air from place to place, Three tyeps, 1. Sex-Pheromone : These attact male and female animal, for reproduction Examples Muskone, Civetone, 2. Aggregation pheromone: Sendingmessage to, othermember of the socity of insect, to help in aggregation, Example Geradial in honeybee, 3. Alarm pheromones: Alarm other member of same, species of insect. Example Formic acid in ants., , www.gneet.comP a g e | 37

Page 40 :
www. gneet.com, , 18.0 Distinguish, 18.1 EnzymeVs Hormone, , 1, , Enzyme, , Hormone, , Always proteinaceous, , May be proteinaceous or amine, or steriod, , 2 High molecular weight, , Low molecular weight, , 3 They may act at site, where they are produced, or carried to another site, by some duct, , They are produced at one, site and are passed by blood, to another site for action, , 4 Acts slowly, but increases, rate of reaction, , Accelerate or retard the, specific reaction. May act, slowly or quick, , 5 Catalyze reversible, reaction, , Hormone controlled, reactions are not reversible, , 6 Are not used up in, reactions, , Are used up in reaction, , 18.2 Vitamins Vs Hormone, , 1, , Vitamins, , Hormone, , Taken along with food from, , Synthesized in endocrine, , outside. Rarely synthesized in, , glands and some by, , www.gneet.comP a g e | 38

Page 41 :
www. gneet.com, , 2, , 3, , the body, , neurosecretory cells., , Simple organic compounds, , These are steroids or, , like amines, esters, organic, , proteinous or amino acid, , acids etc., , derivatives., , These are generally acts as, , These are excitatory or, , coenzymes or constituents of, , inhibitory in action. They never, , coenzymes for enzyme, , act as coenzymes, , action., 4, , 5, , Vitamins have catalytic, , Hormones directly influence, , action., , gene expressions., , Their deficiency, , Their deficiency and, , (avitaminosis) causes specific, , overproduction cause, , deficiency diseases., , metabolic disorders, , 19.0 Important feedback mechanism, 19.01 (TSH) feedback mechanism, , www.gneet.comP a g e | 39

Page 43 :
www. gneet.com, , 19.04, , Corticotropin releasing hormone or, , TRH feedback mechanism, , Interested to solve Multiple choice questions, Buy MCQ Book at nominal price and get exposure to more, than 450+ solved questions, , Visit, www.gneet.comP a g e | 41