![\"1st](\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2021\/06\/KSEEB-Solutions.png\")
<\/p>\nQuestion 1.
\nWhat is the anterior lobe of pituitary called?
\nAnswer:
\nAdenohypophysis.<\/p>\n
Question 2.
\nPosterior lobe of pituitary is neurohaemal. What does it mean?
\nAnswer:
\nIt means that the posterior lobe of pituitary contains axons of neurosecretory cells in the hypothalamus, which pass through the infundibulum to end in the posterior lobe.<\/p>\n
<\/p>\n
Question 3.
\nWhat is Cushing\u2019s disease?
\nAnswer:
\nIt is the improper accumulation of fat in the body due to hyper secretion of ACTH and cortical hormones of adrenals.<\/p>\n
Question 4.
\nName the disorder characterised by diuresis due to hyposecretion of anti-diuretic hormone.
\nAnswer:
\nDiabetes insipidus.<\/p>\n
Question 5.
\nName the endocrine gland that produces calcitonin and mention the role played by this hormone.
\nAnswer:
\nThyroid.<\/p>\n
Question 6.
\nName the hormone that helps in cell mediated immunity.
\nAnswer:
\nThymosin.<\/p>\n
<\/p>\n
Question 7.
\nA patient complains of constant thirst, excessive passing of urine and low blood pressure. When the doctor checked the patients blood glucose and blood insulin levels, the levels were normal or slightly low. The doctor diagnosed the condition as diabetes insipidus. But he decided to measure one more hormone in patient\u2019s blood. Which hormone does the doctor intend to measure?
\nAnswer:
\nADH (antidiuretic hormone) or vasopressin.<\/p>\n
Question 1.
\nState the function of LH.
\nAnswer:
\na. It stimulates the final maturation and release of the ovum from the Graafian follicle. This process is called ovulation.<\/p>\n
b. It helps in the conversion of the Graafian follicle into corpus luteum. It also stimulate corpus luteum to secrete progesteron.<\/p>\n
c. In males, it stimulates the interstitial cells of the testis called Leydig cells to secrete the male sex hormones called testosterone. So LH is also called ICSH,<\/p>\n
Question 2.
\nName any two gonadotropic hormones, giving a function of each.
\nAnswer:
\na. FSH (Follicle stimulating hormone).<\/p>\n
Function :
\ni. In females it promotes the growth and maturation of the Graafian follicle.
\nii. In females it also stimulates the follicle cells of the ovary to secrete female sex hormone or estrogen.
\nb. LH (Luteinizing hormone).<\/p>\n
<\/p>\n
Function :
\ni. In females, stimulates final maturation and release of the ovum from the Graafian follicle.
\nii. It in females helps in the conversion of the Graafian follicle into corpus luteum. It stimulates corpus luteum to secrete progesteron.
\niii. In males, it stimulates the interstitial cells of the testis called Leydig cells to secrete the male sex hormones called testosterone.<\/p>\n
Question 3.
\nDefine the following:
\n(a) Exocrine gland.
\n(b) Endocrine gland.
\n(c) Hormone.
\nAnswer:
\n(a) Duct bearing glands, which release their secretions to the target organs directly through the ducts are called exocrine glands e.g: Salivary glands.<\/p>\n
(b) Ductless glands which release their secretions to the blood circulation are called endocrine glands,
\ne.g : Pituitary gland.<\/p>\n
(c) Hormones are your body’s chemical messengers. They travel in your bloodstream to tissues or organs. They work slowly, over time, and affect many different processes, including. Growth and development. Metabolism – how your body gets energy from the foods you eat<\/p>\n
Question 4.
\nList the hormones secreted by the following:
\n(a) Hypothalamus
\n(b) Pituitary
\n(c) Thyroid
\n(d) Parathyroid
\n(e) Adrenal
\n(f) Pancreas
\n(g) lestis
\n(h) uvary
\n(i) Thymus
\n(j) Atrium
\n(k) Kidney
\n(m) G- I Tract.
\nAnswer:
\n(a) Hypothalamus:
\nThe hypothalamus plays a major role in homeostasis. It collects information from other regions of the brain and from the blood flowing through its vessels to regulate the activity of the pituitary. This regulation of pituitary activity is through the hormones of hypothalamus. The neurons of the hypothalamus secrete two types of hormones, namely the releasing hormones which stimulate the secretion of hormones and inhibiting hormones which prevent the secretion of hormones by pituitary.<\/p>\n
(b) The pituitary gland weighs about 0.5 gm and is pea-sized endocrine gland that lies on the ventral surface of the brain attached to hypothalamus by a nervous stalk called infundibuluin.<\/p>\n
It is called master gland or conductor of endocrine orchestra as several of its hormones control other endocrine glands directly. The hormones of pituitary that influence other endocrine glands are called tropins or trophic hormones. However, the pituitary gland itself works under the influence of hypothalamus through releasing factors. Pituitary gland is called master gland because it controls the functions of other endocrine glands by secreting hormones.<\/p>\n
<\/p>\n
(c) Parathyroid :
\nThere are usually four parathyroid glands (a superior pair and an inferior pair) embedded in the posterior surfaces of lateral lobes of thyroid gland. These glands secrete parathyroid hormone (PTH). PTH induces increase in blood calcium levels by acting on the bones, kidney and intestine.<\/p>\n
It increases the activity of osteoclasts (bone destroying cells) releasing calcium into the blood. it induces the kidney tubules to increase the reabsorption of calcium and magnesium from the urine into the blood, it promotes excretion of phosphates through the urine. It also promotes the formation of calcitriol (active form of vitamin D) which in turn increases the absorption of calcium, phosphate, and magnesium into the blood through the gastrointestinal tract.<\/p>\n
Hypoparathyroidism results in tetany where blood calcium levels fall and induce the neurons to depolarize without the usual stimulus, which leads to the watching of muscles (spasms and convulsions are also seen).<\/p>\n
Hyperparathyroidism induces demineralization of bones leading to elevated blood calcium levels. The areas of destroyed hone tissue become occupied by fibrous tissue. This condition is called osteitis fibrosa cystica. The bones become deformed, delicate and are easily fractured.<\/p>\n
(d) Parathyroid glands are four small glands of the endocrine system which regulate the calcium in our bodies.<\/p>\n
(e) Adrenal glands, also known as suprarenal glands, are small, triangular-shaped glands located on top of both kidneys.<\/p>\n
(f) The pancreas is an organ located in the abdomen. It plays an essential role in converting the food we eat into fuel for the body’s cells. The pancreas has two main functions: an exocrine function that helps in digestion and an endocrine function that regulates blood sugar.<\/p>\n
<\/p>\n
(g) Testis: Testies performs a dual function. It is an exocrine gland i.e. a cytogenic gland producing sperms and an endocrine gland producing testosterone.<\/p>\n
Eighty percent of testis is composed of highly coiled seminiferous tubules involved in spermatogenesis. The endocrine cells secreting testosterone are called Leydig cells or interstitial cells. These are located in the connective tissue between the seminiferous tubules.<\/p>\n
(h) The thymus lies just below the breast bone. ( Image credit: Nerthuz\/Shutterstock) Though the thymus is a little-known organ in the body, it does some very important things. It is part of the lymphatic system, along with the tonsils, adenoids and spleen, and it’s also part of the endocrine system.<\/p>\n
(J) Atrium is the market leader in analytics, AI, and intelligent solutions. We help businesses make smarter decisions and act on them<\/p>\n
(K) The kidneys are a pair of bean-shaped organs on either side of your spine, below your ribs and behind your belly. Each kidney is about 4 or 5 inches long, roughly the size of a large fist. The kidneys job is to filter your blood.<\/p>\n
(I) The gastrointestinal tract (GI tract, GIT, digestive tract, digestion tract, alimentary canal) is the tract from the mouth to the anus which includes all the organs of the digestive system in humans and other animals.<\/p>\n
<\/p>\n
Question 5.
\nWrite short notes on the functions
\n(a) Parathyroid hormone (PTH).
\n(b) Thyroid hormones.
\n(c) Thymosins
\n(d) Androgens.
\n(e) Estrogens.
\n(I) Insulin and Glucagon.
\nAnswer:
\n(a) parathyroid hormone (PTH). PTH induces increase in blood calcium level: by acting on the bones, kidney and intestine. It increases the activity of osteoclasts (bone destroying cells) releasing calcium into the blood. It induces the kidney tubules to increase the reabsorption of calcium and magnesium from the urine into the blood, it promotes the excretion of phosphates. through the urine.<\/p>\n
It also promotes the formation of calcitriol (active form of vitamin D) which in turn increases the absorption of calcium, phosphate, and magnesium into the blood through the gastrointestinal tract.<\/p>\n
Hypoparathyroidism results in tetany where blood calcium levels fall and induce the neurons to depolarize without the usual stimulus, which leads to twitching of muscles (spasms and convulsions are also seen).<\/p>\n
Hyperparathyroidism induces demineralization of bones leading to elevated blood calcium levels. The arcas of destroyed hone tissue become occupied by fibrous tissue. This condition is called osteitis fibrosa cystica. The bones become deformed, delicate and are easily fractured.<\/p>\n
(b) The hyposecrelion of th\u00fdroid hormones during foetal life and infancy results in cretinism characterized by physical and mental retardation of the child. Cretins also exhibit retarded sexual development.<\/p>\n
(c) Thymus
\nThe thymus is a bibbed gland situated in the thorax lying in front of aorta and heart behind the sternum. It is the site of production of T lymphocytes involved in the cell mediated immunity. Thymus also serves as a endocrine gland and secretes a number of hormones that induce proliferation and maturation of T lymphocytes (The hormones of thymus are Thymosin, thymic humoural factor, thymic factor and thymopoietin). The thymus gland decreases rapidly in its size after puberty.<\/p>\n
(d) Androgens are a group of hormones that play a role in male traits and reproductive activity. Present in both males and females, the principle androgens are testosterone and androstenedione. Androgens may be called “male hormones,”<\/p>\n
(e) Estrogen: Estrogen is the female sex hormone secreted by the Graafian follicle and corpus luteum of
\nthe ovary. Estrogen is responsible for the development of accessory reproductive structures like uterus, fallopian tube, development of secondary sexual characters of the female such as rounded contours of the body, high pitch voice, induces development of mammary glands, responsible for growth of endometrium (the endometrium becomes thick with development of glands and increased supply of blood), and controls menstrual cycles (this function is performed along with progesterone). The presence of normal menstrual cycle reflects the health of uterus and fertility of the female. Estrogen increases protein anabolism.<\/p>\n
<\/p>\n
(f) Insulin:<\/p>\n
Glucagon:<\/p>\n
Question 6.
\nState the function of LH.
\nAnswer:
\na. It stimulates the final maturation and release of the ovum from the Graafian follicle. This process is called ovulation.<\/p>\n
b. It helps in the conversion of the Graafian follicle into corpus luteum. It also stimulate corpus luteum to secrete progesteron.<\/p>\n
c. In males, it stimulates the interstitial cells of the testis called Leydig cells to secrete the male sex hormones called testosterone. So LH is also called ICSH.<\/p>\n
Question 7.
\nGive example of:
\n(a) Hyperglycemic hormone and hypoglycemic hormone
\n(b) Hypercalcemic hormone
\n(c) Gonadotropin hormones
\nAnswer:
\n(a) Glucagon, Insulin
\n(b) Parathormone (PTH).
\n(c) Follicle stimulating hormone (FSH, in both sexes), luteinising hormone (LH in females), interstitial cell stimulating hormone (ICSH, in males)<\/p>\n
<\/p>\n
Question 8.
\nBriefly mention the mechanism of action of FSH.
\nAnswer:
\nIn males, FSH and androgens regulate spermatogenesis. In females, FSH is responsible for growth and development of the ovarian follicles, maturiation of egg and secreation of estrogens.<\/p>\n
Question 9.
\nWhat is the role played by the luteinizing hormones, in males and females respectively?
\nAnswer:
\nIn Males : Activation of Leydig cells (interstitial cells) to secrete testosterone and other androgens. Also called interstitial cell stimulating hormone.<\/p>\n
In Females: Stimulates ovulation, development of corpus luteum and secretion of progesterone, menses or pregnancy.<\/p>\n
Question 10.
\nWhat is the role of a second messenger in hormone action?
\nAnswer:
\nSecond messenger is generally active in those cases whose hormone does not enter the cell but interacts with a surface receptor. The inner part of activated receptor takes part in the synthesis of second messenger, e.g., CAMP. The second messenger then acts on a predetermined biochemical pathway to carry out the function of the hormone.<\/p>\n
Question 1.
\nState whether true or false :
\n(a) Gastrointestinal tract, kidney and heart also produce hormones.
\n(b) Pars distalis produces six trophic hormones.
\n(c) B-lymphocytes provide cell mediated immunity.
\nAnswer:
\n(a) True
\n(b) False
\n(c) False.<\/p>\n
<\/p>\n
Question 2.
\nMatch the hormones in column I with their chemical nature in column II.
\nColumn I — Column II
\n(a) Oxytocin — (i) Amino acid derivative
\n(b) Epinephrine — (ii) Steroid
\n(c) Progesterone — (iii) Protein
\n(d) Growth — (iv) Peptide
\nAnswer:
\n(a) (iv), (b) (i), (c) (ii), (d) (iii).<\/p>\n
Question 1.
\nName any two gonadotropic hormones giving a function of each.
\nAnswer:
\na. FSH (Follicle stimulating hormone).<\/p>\n
Function :<\/p>\n
b. LH (Luteinizing hormone).<\/p>\n
Function :
\ni. It stimulates in females, the final maturation and release of the ovum from the Graafian follicle.
\nii. It helps in females in the conversion of the Graafian follicle into corpus luteum. It stimulates corpus luteum to secrete progesteron.
\niii. In males it stimulates the interstitial cells of the testis called Leydig cells to secrete the male sex hormones called testosterone.<\/p>\n
Question 2.
\nGive the target galands for the given harmones.
\nHormones: — Target gland:
\n(a) Hypothalamic hormones — …………………………….
\n(b) Thyrotrophin (TSH) — …………………………….
\n(c) Corticotrophin (ACTH) : — …………………………….
\n(d) Gonadotrophins (LH. FSH) — …………………………….
\n(e) Melanotrophin (MSH) — …………………………….
\nAnswer:
\n(a) Pituitary
\n(b) Thyroid
\n(c) Adrenal cortex
\n(d) Gonads
\n(e) Skin.<\/p>\n
<\/p>\n
Question 3. Question 4. The axons of these neurons end in the basal region of the hypothalamus called median eminence. The venules which collect the blood from median eminence form a second set of capillaries in the anterior pituitary. This vascular link between the hypothalamus and the anterior pituitary is called hypothalamo-hypophyseal portal system and it delivers the hormones from the hypothalamus to the anterior pituitary. The following table shows the main hypothalamic hormones and their \u00e8ffects on pituitary.<\/p>\n Question 5. Endocrine glands and hormones: Human endocrine system: Hypothalamus: The axons of these neurons end in the basal region of the hypothalamus called median eminence. The venules which collect the blood from median eminence form a second set of capillaries in the anterior pituitary. This vascular link between the hypothalamus and the anterior pituitary is called hypothalamo-hypophyseal portal system and it delivers the hormones from the hypothalamus to the anterior pituitary, The following table shows the main hypothalamic hormones and their effects on pituitary. The hormones of hypothalamus and their effects on anterior pituitary.<\/p>\n Endocrine functions of pituitary glands : Pituitary Gland (OR) Hypophysis : It is called master gland or conductor of endocrine orchestra as several of its hormones control other endocrine glands directly. The hormones of pituitary that influence other endocrine glands are called tropins or trophic hormones. However, the pituitary gland itself works under the influence of hypothalamus through releasing factors. Pituitary gland is called master gland because it controls the functions of other endocrine glands by secreting hormones.<\/p>\n Based on origin, it is divided into two parts namely Adenohypophysis and Neurohypophysis.<\/p>\n I. Adenohypophysis (Anterior Pituitary) : Adenohypophysis is further divided into three regions : Pars distalis, Pars intermedia and Pars tubelaris. Pars intermedia degenerates during foetal development and occurs only as a small strip in adults. Pars tubelaris has no functional significance. Adenohypophysis cells secrete seven major hormones.<\/p>\n 1. Somatotrophic hormone or Human growth hormone (STH or HGH) : Promotes the growth of muscles. It stimulates uptake of amino acids by tissues and their synthesis into proteins.<\/p>\n 2. Thyroid stimulating Hormone (TSH): Controls secretion of thyroid hormones by thyroid gland and also regulates iodine intake by the thyroid gland.<\/p>\n 3. Adrenocorticotrophic hormone (ACTH) : It controls the( secretion of hormones (Cortisone) by adrenal cortex.<\/p>\n 4. Follicle Stimulating Hormone (FSH) : In females the induces growth and maturation of Graffian follicle and stimulates follicular secretion of estrogen. In males, it stimulates testis to produce sperm.<\/p>\n 5. Luteinizing Hormone or Interstitial Cell Stimulating Hormone (LH or ICSH) : In females, it stimulates ovulation and formation of corpus luteum. In males, it stimulates interstitial cells in testis to secrete testosterone.<\/p>\n 6. Prolactin or Lactogenic or Luteotropic Hormone (LTH) : In females it causes growth and development of breast during pregnancy. It stimulates milk production and secretion after childbirth. It inhibits ovulation during pregnancy and breast-feeding.<\/p>\n 7. Melanocyte Stimulating Hormone (MSH) : Increases skin pigmentation by stimulating dispersion of melanin in amphibians but its exact role in humans is unknown.<\/p>\n II. Neurohypophysis (Posterior Pituitary): 1. Oxytocin (Birth hormone or Milk ejection hormone) : Induces contraction of smooth muscle fibers of uterus during labour (childbirth), contraction of blood vessels of uterus after childbirth to prevent blood loss, contraction, of female genital tract for transport of sperm after copulation and ejection of milk by lactating breast. Since it helps during delivery, it is commonly called delivery hormone.<\/p>\n 2. Vasopressin or Antidiuretic hormone (ADH) : Decreases urine volume by causing water reabsorption in the collecting ducts of kidneys. Also raises B.P. by contraction of blood vessels during severe haemorrhage.<\/p>\n Pineal gland: Thyroid gland: The thyroid gland is composed of microscopic sacs called thyroid follicles. The walls of these follicles are largely composed of cuboidal cells called follicular cells. Between the follicles lying in the interstitial tissue are more or less oval shaped cells called parafollicular cells. Sometimes the parafollicular cells are present in the wall of follicles between the follicular cells.<\/p>\n The follicular cells, under the influence of TSH secrete tetra iodothyroine (T4) or thyroxine and tri iodothyronine (T4). Functions of thyroid hormone: 2. With growth hormone and insulin, thyroid hormones accelerate body growth. They promote the normal growth and maturation of skeleton, promote the normal development of nervous system in foetus and infant, normal functioning of the nervous system in adults.<\/p>\n 3. Stimulate protein synthesis, induce lipolysis and increase the use of glucose for ATP production.<\/p>\n 4. Promote the normal development and functioning of reproductive organs.<\/p>\n 5. Promote the secretory activity of the skin and maintain normal levels of water in the skin. The calcitonin produced by the thyroid with the parathyroid hormone regulates the calcium levels in the blood. Calcitonin inhibits osteoclast (bone destroying cell) activity and hence inhibits bone breakdown. It accelerates the uptake of calcium by bones. Thus the blood calc ium level is lowered. Calcitonin is antagonist of parathyroid hormone.<\/p>\n Hyposecretion and hypersecretion of thyroid hormone: Hypothyroidism in adults causes myxoedema: enlarges resulting in endemic goiter or colloidal goiter. In the absence of sufficient amount of iodine intake, the thyroid gland can not produce the required amounts of thyroid hormones. This results in the failure of normal negative feed back inhibition of pituitary, hence there is high levels of TSH secretion which in turn induces abnormal growth of the thyroid. The myxoedema can be reversed by iodine supplements or hormone replacement therapy. Hyperthyroidism during adulthood can lead to Grave\u2019s disease.<\/p>\n This is also known as thyrotoxicosis, toxic goiter or exophthalmic goiter. This is an autoimmune disease. The individual produces antibodies that mimic the action of TSH. The production of these antibodies is not inhibited by negative feedback mechanism of high levels of thyroxine. Hence the thyroid gland becomes enlarged and secretes thyroxine in excessive amounts.<\/p>\n The disease is characterized by weight loss, nervousness, rapid reflexes, irritability, increased BMR, intolerance to heat, bulging eyes (exophthalmus), increased cardiac output and blood pressure.<\/p>\n Parathyroid glands: It increases the activity of osteoclasts (bone destroying cells) releasing calcium into the blood. It induces the kidney tubules to increase the reabsorption of calcium and magnesium from the urine into the blood. It promotes excretion of phosphates through the urine.<\/p>\n It also promotes the formation of calcitriol (active form of vitamin D) which in turn increases the absorption of calcium, phosphate, and magnesium into the blood through the gastrointestinal tract.<\/p>\n Hypoparathyroidism results in tetany where blood calcium levels fall and induce the neurons Hyperparathyroidism induces demineralization of bones leading to elevated blood calcium levels. The areas of destroyed bone tissue become occupied by fibrous tissue. This condition is called osteitis fibrosa cystica. The bones become deformed, delicate and are easily fractured.<\/p>\n Thymus Adrenal glands (i) Adrenal Medulla. These hormones increase alertness, dilations of pupil, sweating etc. (ii) Adrenal cortex. (a) The hormones secreted by adrenal cortex are collectively called corticoids. (b) The middle layers of cells secrete glucocorticoids cortisol is an example. Glucocorticoids stimulate gluconeogenesis, lipolysis and proteolysis. Cortisol is involved in maintaining the cardiovascular system and kidney functions. Cortisol produces anti-inflammatory reactions and suppresses the immune response. (c) The middle layer and the innermost layer secrete small quantities of androgenic steroids. These play a role in the growth of axial hair, public hair and facial hair during puberty.<\/p>\n Pancreas: (i) Glucagon: (ii) Insulin: . Diabetes Mellitus: Insulin dependent diabetes mellitus (IDDM) is a condition, which occurs when there is a quantitative deficiency of insulin. The condition is common in children and is, hence, also known as juvenile diabetes. Such patients will have to be placed on insulin therapy.<\/p>\n Non Insulin dependent diabetes mellitus (NIDDM) is a conditionwhere enough insulin is produced but not utilized efficiently due to some functional disorder. Generally it occurs in adults, particularly after the age of 40. Therefore, it is also known as maturity-onset diabetes. In the early stages, it can be treated by oral anti-diabetic drugs.<\/p>\n Symptoms: Treatment: Gonads: Testis: 2. Eighty percent of testis is composed of highly coiled seminiferous tubules involved in spermatogenesis. The endocrine cells secreting testosterone are called Leydig cells or interstitial cells. These are located in the connective tissue between the seminiferous tubules.<\/p>\n 3. The Leydig cells under the influence of LH of pituitary secrete testosterone (male sex hormone) which has the following functions.<\/p>\n It induces spermatogenesis in the testies. It brings about the development of accessory reproductive structures in males such as epididymis, vasa deferentia, seminal vesicles, prostrate gland, urethra and also the penis and scrotum, brings about expressions of secondary sexual characters such as beard and moustache, induces better development of skeletal and muscular tissues, brings about retention of Na, K, P, induces protein anabolism and brings about enlargement of thyroid cartilage of larynx forming Adam\u2019s apple.<\/p>\n The voice becomes low pitched and it regulates sex drive \/ libido in male. Sertoli cells of testes secrete a hormone called Inhibin. This inhibits release of GnRF (Gonadotropin releasing factor) from the hypothalamus. As a result the pituitary does not secrete FSH and LH.<\/p>\n Ovaries: Estrogen: Progesterone: Relaxin: Inhibin: Hormone from Kidney: Hormones from Gastro-Intestinal Tract The mucosa of small intestine secretes gastric inhibitory peptide which inhibits gastric motility and secretion. Mechanism of hormone action: Water soluble hormone action: 1. The hormone binds to its specific membrane receptor of the target cell. Lipophilic hormone action: The lipophilic steroid hormones and thyroid hormones pass through the plasma membrane and get bound to a specific intracellular receptor. These receptors are commonly located within the nucleus. Once these nuclear hormone receptors are activated by their binding to specific hormone, they alter the gene expression. They may switch on or off specific genes on the nuclear DNA. The transcription of DNA occurs and the newly formed mRNA directs the synthesis of specific enzyme proteins. These enzymes alter the metabolism of the cell in the required direction as per the intended action of hormone.<\/p>\n Karnataka 1st PUC Biology Question Bank Chapter 22 Chemical Coordination and Integration 1st PUC Biology Chemical Coordination and Integration One Marks Questions and Answers Question 1. What is the anterior lobe of pituitary called? Answer: Adenohypophysis. Question 2. Posterior lobe of pituitary is neurohaemal. What does it mean? Answer: It means that the posterior lobe …<\/p>\n","protected":false},"author":5,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[81],"tags":[],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/posts\/88676"}],"collection":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/comments?post=88676"}],"version-history":[{"count":0,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/posts\/88676\/revisions"}],"wp:attachment":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/media?parent=88676"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/categories?post=88676"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/tags?post=88676"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\nWhich hormonal deficiency is responsible for the following:
\n(a) Diabetes mellitus
\n(b) Goitre
\n(c) Cretinism
\nAnswer:
\n(a) Insulin
\n(b) Thyroxine (T4<\/sub> or tetraiodothyronine) and T3<\/sub> (triiodothyronine)<\/p>\n
\nHypothalamus is a supermaster endocrine gland. Elaborate.
\nAnswer:
\nThe hypothalamus plays a major role in honicostasis. It collects information from other regions of the brain and from the blood flowing through its vessels to regulate the activity of the pituitary. This regulation of pituitary activity is through the hormones of hypothalamus. The neurons of the hypothalamus secrete two types of hormones, namely the releasing hormones which stimulate the secretion of hormones and inhibiting hormones which prevent the secretion of\u2019 hormones by pituitary.<\/p>\n<\/p>\n
\nDiagrammatically indicate the location of the various endocrine glands in our body.
\nAnswer:
\n![\"1st](\"https:\/\/kseebsolutions.guru\/wp-content\/uploads\/2021\/06\/1st-PUC-Biology-Question-Bank-Chapter-22-Chemical-Coordination-and-Integration.1.png\")
<\/p>\n1st PUC Biology Chemical Coordination and Integration Text Book Questions and Answers<\/h3>\n
\nEndocrine system consists of endocrine glands that lack ducts and secrete their products called hormones into the blood. The blood carries the hormones to target cells. These cells Have receptors (proteins or glycoproteins) that bind and recognize a specific hormone. This induces a specific change in the target cell.
\nDefinition of Hormone: Hormones are biochemical messengers secreted in minute quantities at a place and are transported to a target cell to induce a specific change in the target cell. Hormones have many functions.<\/p>\n
\nHuman endocrine system includes endocrine glands such as Pituitary, Thyroid, Parathyroid, Adrenal, Islets of Langerhans of Pancreas, Ovary, Testis and Pineal.<\/p>\n<\/p>\n
\nThe hypothalamus plays a major role in homeostasis. It collects information from other regions of the brain and from the blood flowing through its vessels to regulate the activity of the pituitary. This regulation of pituitary activity is through the hormones of hypothalamus. The neurons of the hypothalamus secrete two types of hormones, namely the releasing hormones which stimulate the secretion of hormones and inhibiting hormones which prevent the secretion of hormones by pituitary.<\/p>\n\n\n
\n Hypothalamic hormone<\/strong><\/td>\n Effect on anterior pituitary<\/strong><\/td>\n<\/tr>\n \n 1.\u00a0\u00a0 Growth hormone releasing hormone (GHRH).
\n2.\u00a0\u00a0 Growth Hormone release\u00a0inhibiting hormone (GHRIH) (Somatostatin)
\n3.\u00a0\u00a0 Prolactin – releasing hormone (PRH).
\n4.\u00a0\u00a0 Prolactin – inhibiting hormone (PIH).
\n5.\u00a0\u00a0 Thyrotrophin releasing hormone (TRH). hormone
\n6.\u00a0\u00a0 Gonadotrophin releasing hormone (GnRH). hormone and Luteinizing hormone.
\n7.\u00a0\u00a0 Corticotrophin releasing hormone (CRH), hormone.<\/td>\nStimulates secretion of growth hormone. Inhibits secretion of growth hormone.
\nStimulates secretion of prolactin.
\nInhibits the secretion of prolactin.
\nStimulates secretion of Thyroid stimulating
\nStimulates secretion of Follicle stimulating
\nStimulates secretion of adrenocorticotrophic<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
\nPituitary is a endocrine gland attached to the hypothalamus of the brain by a stalk called Infundibulum. It lies at the base of the brain in a depression called sellaturcica. Pituitary gland is also known is Hypophysis. ,<\/p>\n
\nThe pituitary gland weighs about 0.5 gm and is pea sized endocrine gland that lies on the ventral surface of the brain attached to hypothalamus by a nervous stalk called infundibulum.<\/p>\n<\/p>\n
\nIt accounts for nearly 75% of the total weight of the gland. It is derived from the buccal cavity in the form of a projection-called Rathke\u2019s pouch.<\/p>\n\n
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\nPosterior pituitary is called Neurohypophysis since it is derived from hypothalamus (or floor of the brain). It includes pars nervosa and infundibulum. Pars nervosa is composed of nerve fibers supported by pituicytes. The cell bodies of these neurons are located in the hypothalamus, that secrete the hormones and are subsequently released through neurohypophyseal vein and stored in pars nervosa. These secretary cells are called neurosecretory. They produce two neurohormones.<\/p>\n\n
\nThe pineal gland is a small cone shaped gland attached to the roof of the third ventricle of diencephalon. The principal hormone of pineal gland is melatonin. Melatonin helps in maintaining the circadian rhythms (rhythms of physiological activities that follow a 24 hour pattern) in accordance with light – dark cycle of each day.<\/p>\n\n
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\nThyroid gland is a bilobed gland situated on the trachea just below the voice box. The two lobes are connected by a mass of tissue called isthmus.<\/p>\n
\nT3 and T4 together referred to as thyroid hormones. The parafollicular cells secrete the hormone called calcitonin.
\nThe follicular cells synthesise thyroglobulin, a glycoprotein and release it into the lumen of the follicle where it accumulates forming colloid. To this colloid the synthesized T4 and T3 get bound. T4 is usually secreted in greater quantity than T3, however T3 is more active.<\/p>\n
\n1. Increase the basal metabolic rate (BMR) by promoting the cellular respiration. The cells use more oxygen to produce ATP, releasing more heat and the body temperature increases. This is known as calorigenic effect of thyroid hormones.<\/p>\n<\/p>\n
\nThe hyposecretion of thyroid hormones during foetal life and infancy results in cretinism characterized by physical and mental retardation of the child. Cretins also exhibit retarded sexual development.<\/p>\n
\nThis is characterized by general oedema (swelling of face, hands and feet), physical and mental lethargy, reduced BMR, low body temperature, slow heart rate, sensitivity to cold, thick, dry skin and dry hair. If myxoedema is due to deficiency of iodine, then thyroid gland<\/p>\n
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\nThere are usually four parathyroid glands (a superior pair and an inferior pair) embedded in the posterior surfaces of lateral lobes of thyroid gland (Fig. 22.3). These glands secrete parathyroid hormone (PTH). PTH induces increase in blood calcium levels by acting on the bones, kidney and intestine.<\/p>\n
\nto depolarize without the usual stimulus, which leads to twitching of muscles (spasms and convulsions are also seen).<\/p>\n
\nThe thymus is a bilobed gland situated in the thorax lying in front of aorta and heart behind the sternum. It is the site of production of T lymphocytes involved in the cell mediated immunity. Thymus also serves as a endocrine gland and secretes a number of hormones that induce proliferation and maturation of T lymphocytes (The hormones of thymus are Thymosin, thymic humoural factor, thymic factor and thymopoietin). The thymus gland decreases rapidly in its size after puberty.<\/p>\n
\nThese are paired glands lying above the kidneys. Each gland structurally and functionally differentiated into an outer adrenal cortex and an inner adrenal medulla.’<\/p>\n
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\nIt secretes two hormones:
\n(a) Adrenaline or epinephrine.
\n(b) Noradrenaline or norepinephrine.
\nBoth the hormones are catecholamines in response to stress and during emergency situations, they are called emergency hormones or hormones of fight or flight.<\/p>\n<\/p>\n
\nThey also increase the heart beat rate, strength of heart contraction and the rate of respiration.
\nThey stimulate the breakdown of glycogen and increase the concentration of glucose in blood. They also stimulate the break down of fats and proteins.<\/p>\n
\nAdrenal cortex can be divided into three layers:
\n(a) The innermost layer zona reticularis.
\n(b) The middle layer zona fasciulata.
\n(c) The outer layer zona glomerulosa.<\/p>\n
\nIt regulates the balance of water and electrolytes in the body.<\/p>\n
\nIt also stimulates the production of erythrocytes.<\/p>\n
\nThe pancreas is both an exocrine and an endocrine gland. For its endocrine function, it has islets of Langerhans. These islets have b (beta) or B cells, a (alpha) or A cells and (delta) or D cells. The B cells secrete insulin and A cells secrete glucagon. Both are proteinaceous hormones regulating the blood glucose levels.
\nThe D cells secrete a hormone called somatostatin. It inhibits the digestion and absorption of nutrients. It also inhibits the secretion of insulin and glucagon.<\/p>\n
\nIt is a peptide hormone.
\nIt is a hyperglycemic hormone, i.e., it increases the level of glucose.
\nIt acts on the liver cells and hepatocytes in the blood.
\nIt stimulates glycogenolysis and increases the level of glucose in the blood.
\nIt stimulates gluconeogenesis and synthesis of glucose from amino acids.<\/p>\n
\nIt is a peptide hormone.
\nIt is a hypoglycemic hormone, i.e., it reduces the level of glucose in blood by stimulating the uptake and utilisation of glucose by tissue cells.
\nIt acts on the hepatocytes and stimulates conversion of glucose into fats.
\nIt also acts on adipocytes and stimulates conversion of glucose into fats.
\nDeficiency of insulin causes hyperglycemia and prolonged hyperglycemia results in diabetes mellitus<\/p>\n<\/p>\n
\nA condition characterized by an increase in the blood sugar level (hyperglycemia), caused by hyposecretion of insulin. There are two types of diabetes mellitus.<\/p>\n
\nHyperglycemia – An increase in blood glucose level (concentration).
\nGlucosuria – Presence glucose in urine.
\nPolyuria – Increased production of urine.
\nPolydipsia – Excessive loss of water and salts due to polyuria.
\nDehydration – Excessive eating.
\nLoss of weight – Cataboli\u0161m of storied fats and proteins leading to loss of weight.
\nKetosis (keto acidosis) – Excessive fat metabolism leading to accumulation of ketone bodies like acetone and acetoacetic acid.
\nDelayed t\u00ecsue repair – High sugar level in the blood, reduces resistance of bacterial infections and hence, an abnormal delay in wound healing.
\nDiabetic coma and death – Most of the above effects produce drowsiness, leading to diabetic coma and death, if untreated.<\/p>\n<\/p>\n
\nAdministration of appropriate doses of insulin is very effective Hypoglycemic drugs like talbutamide etc., are also used.<\/p>\n
\nTestes and Ovary are primary sex organs of male and female respectively and are called gonads.<\/p>\n
\n1. Testies performs a dual function. It is an exocrine gland i.e, a cytogenic gland producing sperms and an endocrine gland producing testosterone.<\/p>\n<\/p>\n
\nOvary secretes Estrogen, Progesterone, Relaxin and Inhibin.<\/p>\n
\nEstrogen is the female sex hormone secreted by the Graafian follicle and corpus luteum of the ovary. Estrogen is responsible for the development of accessory reproductive structures like uterus, fallopian tube, development of secondary sexual characters of the female such as rounded contours of the body, high pitch voice, induces development of mammary glands, responsible for growth of endometrium (the endometrium becomes thick with development of glands and increased supply of blood), arid controls menstrual cycles (this function is performed along with progesterone). The presence of normal menstrual cycle reflects the health of uterus and fertility of the female. Estrogen increases protein anabolism.<\/p>\n
\nProgesterone is a steroid hormone secreted by the corpus luteum of the ovary under the influence of LH of pituitary. Progesterone is indispensable for pregnancy. (The endometrial glands of the uterus become functional and endometrium is prepared for implantation). It induces development of mammary’ glands for milk secretion and desensitizes the uterus to the actions of oxytocin and prostaglandins. It inhibits the release of FSH and LH.<\/p>\n
\nRelaxin is a proteinaceous hormone secreted both by the ovary (corpus luteum) and placenta.
\nRelaxin softens fibrous cartilage at pubic symphysis, thereby relaxes arid widens the pelvis at the time of parturition.<\/p>\n
\nInhibin is secreted by the corpus luteum. It is a proteinaceous hormone. It inhibits the release of GNRF from the hypothalamus, and pituitary does not release FSH and LH.<\/p>\n\n
\nThe kidneys produce the hormone erythropoietin (EPO). This is produced in response to the inadequate supply of oxygen to the kidney cells. Erythropoietin is a glycoprotein hormone and it directly stimulates erythrocyte production (erythropoiesis) in the red bone marrow.<\/p>\n
\nThe mucosa of gastrointestinal tract in response to food, secretes several hormones to regulate the process of digestion. Stomach secretes the hormone gastrin in response to the entry of food, to stimulate the gastric glands. In response to this, the parietal cells secrete hydrochloric acid and chief cells secrete pepsinogen. The mucosa of duodenum secretes secretin and cholecystokinin. Secretin stimulates the pancreas, to release water and a bicarbonate rich secretion. Cholecystokinin stimulates the pancreas to secrete a enzyme rich secretion. It also induces the contraction of gall bladder and relaxation of sphincter of Oddi causing the flow of bile and pancreatic juice into the duodenum.<\/p>\n<\/p>\n
\nThe mucosa of ileum and colon secretes glucagon like peptide which inhibits the gastric motility and secretion.
\nThe adipose tissue secretes hormones leptin and resistin. The leptin\u2019s target is brain and it inhibits appetite. Resistin antagonizes the action of insulin on fat, muscle and liver cells.<\/p>\n
\nHormones exert their effects on target cells by interacting with specific receptors of these cells. These receptors are proteins or lipoproteins. The location of the hormone receptor depends on the chemical nature of the hormone. The water soluble hormones (polypeptides, glycoproteins and catecholamines) cannot pass through the plasma membrane, hence their receptors are located on the outer surface of the membrane.<\/p>\n
\nThe lipophilic hormones (steroids and thyroxine) can pass through the plasma membrane and enter into their target cells, hence the receptors for these hormones are located within the nucleus and cytoplasm.
\nThe water soluble hormones have their action mediated through second messengers. When these hormones bind to their specific receptors of the plasma membrane specific membrane proteins become activated to generate second messengers
\nCyclic AMP, phospholipase C, inositol triphosphate, diacyl glycerol and Ca++ act as second messengers.
\nCyclic AMP second messenger system, has the following sequence of events to effect the action of hormone.<\/p>\n
\n2. G proteins linked to specific receptors activate the enzyme adenylate cyclase.
\n3. Activated adenylate cyclase, converts ATP to cyclic AMP.
\n4. Cyclic AMP activates protein kinase enzymes of the cytoplasm.
\n5. Protein Kinase phosphorylates (adding phosphate groups to) the other enzymes of the cytoplasm.
\n6. The phosphorylation of specific enzymes may enhance or inhibit their activity.
\n7. This alters the metabolism of the target cell in the required direction as per the specific hormone action.<\/p>\n
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<\/p>\n<\/p>\n1st PUC Biology Question Bank with Answers<\/a><\/h4>\n","protected":false},"excerpt":{"rendered":"