Chemical Coordination And Integration - Class 11 Medical Biology - Extra Questions

Write short on the functions of thymus.

The thymus actively secretes the hormones called thymosins (only till pre-pubescence) Thymosins are peptide hormones which play an important role in 
  • The stimulation, development and differntiation of T-lymphocytes.
  • The development of cell-mediated immunity (T-lymphocytes mediated immunity)
  • The production of antibodies (Humoral immunity).
Thymosin secretion is completely absent in old individuals because of which their immunity becomes weak.


Which endocrine gland is considered "the throne of immunity"?

Thymus is known as "throne of immunity" because it is the site of maturation of T-lymphocytes. Thymosin is the hormone produced by the thymus gland.  Its job is to nurture the lymphocytes, which is a type of white blood cell that plays an important and integral role in the body's defenses. It promotes proliferation and maturation of T-lymphocytes. If one gets severe dose of radiation, enough to knock down the immune system, thymosin must be life saver, stimulating the spleen and the other organs that had shut down to get back into reproduction. 


Name the hormone that regulates fall of calcium ion level in blood and mention the source of it.

There are four parathyroid glands located behind the thyroid gland. It secretes parathormone (PTH). Their main function is to regulate blood calcium levels in the body. When blood calcium levels drop, parathyroid gland secretes PTH. This hormone works to raise blood calcium levels by stimulating osteoclasts to break down bone and release calcium into the bloodstream. PTH also signals the kidneys to conserve calcium by reducing the amount excreted in the urine.


Which hormone regulates calcium balance in body?

There are four parathyroid glands are found in the back side of the thyroid. When blood calcium levels becomes low, the parathyroid gland secrets parathyroid hormone or parathormone(PTH). This hormone helps to raise blood calcium levels by stimulating osteoclasts thatcauses the desorption of bones and releases calcium into the blood. PTH also signals the kidneys to maintain calcium by reducing the amount excreted in urine. PTH increases the formation of active vitamin D, which increases intestinal calcium and phosphorus absorption.


Mention the exact location of the following:
Islets of Langerhans.

The pancreatic islets or islets of Langerhans are the regions of the pancreas that contain cells that produce hormones. They sense blood sugar levels and release insulin to maintain normal levels.
Location of Islets of Langerhans: Pancreas


Name the hormones secreted by the following endocrine glands and specify one function:
Thyroid
Pituitary 
Pancreas

  1. Thyroid: Thyroxin hormone is secreted; regulates carbohydrate, protein, and fat metabolism so as to provide best balance for growth.

  2. Pituitary: Human Growth Hormone, Regulates growth and development, deficiency leads to dwarfism, gigantism if excessive production takes place.

  3. Pancreas: Secretes insulin, regulates blood sugar levels.



Name the hormonal secretion which takes place under the emergency conditions of stress, anger and fear.

Adrenaline and noradrenaline are rapidly secreted in response to the stress of any kind and during emergency situations (like anger and fear). They are called emergency hormones or hormones of Fight or Flight. These hormones increase alertness, pupillary dilation, piloerection (raising of hairs), sweating etc. Both the hormones increase the heartbeat, the strength of heart contraction and the rate of respiration.


Name the hormone that regulates  the sodium and potassium ion metabolism

Aldosterone regulates sodium and potassium ion metabolism. 
Aldosterone is a hormone produced in the outer section (cortex) of the adrenal glands, which sit above the kidneys. It plays a central role in the regulation of blood pressure mainly by acting on organs such as the kidney and the colon to increase the amount of salt (sodium) reabsorbed into the bloodstream and to increase the amount of potassium excreted in the urine. Aldosterone also causes water to be reabsorbed along with sodium; this increases blood volume and therefore blood pressure.


Name the hormone which reduces excess calcium in the blood.

Calcitonin is a hormone which is released by the parafollicular cells (C-cells) of the thyroid gland when the blood calcium level is high. It decreases the calcium level in the blood. It is also important to note here that it plays the opposite role to the PTH (Parathyroid) hormone which increases blood calcium level.


Name the hormone secreted by the thymus gland.

Thymosin is the hormone secreted from thymus gland.
Thymosin stimulates the development of T cells. Throughout childhood years, white blood cells called lymphocytes pass through the thymus, where they are transformed into T cells.


Very short answer type.
What is the cause of abnormal elongation of long bones of arms and legs and of the lower jaw?

Excessive secretion of GH or growth hormone causes abnormal elongation of long bones of arms and legs and of the lower jaw. The condition is called gigantism in young and acromegaly in adults.


Very short answer type.
Name the source gland and give one main action of the following hormones:
oxytocin

Oxytocin is secreted by posterior pituitary. It causes contraction of uterine muscle during childbirth.


Name one gland in the human body which secretes digestive enzymes as well as hormones.

The pancreas secretes both digestive enzymes and hormones. It is known as mixed glad because of its action as both endocrine and exocrine gland. It secretes hormones glucagon and insulin. While the majority of the pancreas is made up of the exocrine portion (85% by mass) and secretes digestive enzymes, water and bicarbonate to assist in digestion.


Name the hormone that regulates calcium level in blood.

The parathormone is secreted by the parathyroid gland. Its main function is to increase the level of calcium in the blood. It promotes the reabsorption of calcium from nephrons and also, promotes the absorption of calcium from digested food. Hence, it plays an important role in maintaining calcium balance in the body.


Very short answer type.
What is the position of the adrenal glands in relation to pancreas and kidneys?

The adrenal glands are anatomically located superior to the kidneys in the retroperitoneal space, at about the same horizontal level as the pancreas. Hence they are also known as suprarenal glands.


Very short answer type.
Name the source gland and give one main action of the following hormones:
calcitonin

Calcitonin is secreted by thyroid gland. Its function is to regulate calcium and phosphate levels in the blood. It tends to lower blood calcium levels.


Very short answer type.
What are tropic hormones?

Tropic hormones are those that stimulate some other endocrine glands to secrete their hormones. These hormones are secreted by anterior pituitary gland.


Very short answer type.
Is pineal gland a vestigial organ? Mention its functions.

No, pineal gland is an endocrine gland, which secretes the hormone melatonin. This hormone produces circadian rhythms and regulates sleep cycle of the body.


Very short answer type.
Name the source gland and give one main action of the following hormones:
vasopressin

Vasopressin is secreted by posterior pituitary. It causes conservation of body water by reabsorbing water from urine.


Very short answer type.
Name the source gland and give one main action of the following hormones:
somatostatin

Somatostatin is secreted by the hypothalamus and also pancreas. It depresses growth hormone secretion and also known as growth hormone inhibiting hormone (GHIH).


Very short answer type.
Name the source gland and give one main action of the following hormones:
parathormone

Parathormone is secreted by parathyroids. It regulates calcium and phosphorus metabolism. It increases blood calcium levels.


Very short answer type.
Name the source gland and give one main action of the following hormones:
thyrotropin

Thyrotropin is secreted by anterior pituitary. It stimulates the release of TSH which causes thyroxine secretion from thyroid gland.


Very short answer type.
Name the source gland and give one main action of the following hormones:
gastrin

Gastrin is secreted by pyloric antrum of the stomach and upper small intestine. It stimulates acid and pepsin secretion which aids in digestion.


Very short answer type.
Name the source gland and give one main action of the following hormones:
glucagon

Glucagon is secreted by islets of Langerhans (pancreas). It raises blood sugar level by acting on liver glycogen.


Very short answer type.
Name the source gland and give one main action of the following hormones:
cholecystokinin

Cholecystokinin or CCK is released from duodenum and upper jejunum. It helps in secretion of pancreatic enzymes and contraction of gallbladder.


Very short answer type.
Name the source gland and give one main action of the following hormones:
estrogen

Estrogen is secreted by ovaries. It stimulates secondary sex organs in females.


Very short answer type.
Name the source gland and give one main action of the following hormones:
testosterone

Testosterone is secreted by the testis. It causes sex differentiation in male foetus and the development of secondary sex characters in males.


Very short answer type.
Name the source gland and give one main action of the following hormones:
TSH

TSH or thyroid stimulating hormone is secreted by anterior pituitary. It stimulates thyroxine secretion by acting on thyroid gland.


Very short answer type.
Name the source gland and give one main action of the following hormones:
tropic hormones

Tropic hormones are secreted by anterior pituitary. It has its effect on growth and metabolism and stimulation of other endocrine glands.


Value based questions.
How quickly do you think- a steroid hormone can start to exert its effect?

Steroid hormones bind to receptors inside target cells, hence the effects of them appear slowly. Even the transportation of steroid hormones through blood requires serum proteins.


Name a parathyroid hormone and describe briefly its function.

The parathyroid glands secrete parathyroid hormone (PTH). The secretion of PTH is regulated by the circulating levels of calcium ions. Parathyroid hormone (PTH) increases the Ca$$^{2+}$$ levels in the blood. PTH acts on bones and stimulates the process of bone resorption (dissolution/demineralisation). PTH also stimulates reabsorption of Ca2+ by the renal tubules and increases Ca$$^{2+}$$ absorption from the digested food. 


The hormone that helps increase the reabsorption of water from the kidney tubules.

Vassopressin/antidiuretic hormone (ADH) is secreted by posterior pituitary gland and targets nephrons to increase water reabsorption from renal tubules and thereby decreasing water content in urine. 
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Which hormone is secreted by adrenal glands? Write any one function of this hormone.

The hormone which is produced by the adrenal glands is aldosterone and cortisol. The aldosterone is the hormone which is responsible for the maintenance and regulation of the electrolytes like sodium and potassium ions and water. This hormone also helps in maintaining the blood pressure by regulating the blood volume. 


Based on relationship fill in the blanks.
Thyroxin: Personality hormone; ...........: Adrenaline

The thyroxine is known as the personality hormone. This hormone is responsible for the regulation of BMR (Basal metabolic rate). This hormone defines the growth and development of the person. Adrenaline is known as the emergency hormone or hormone of flight, fright and fight. This hormone is released under the conditions of stress. This hormone is known as the emergency hormones which are released during the time of emergency. 


Copy the diagram given below and write the names of A and B in the parts of thyroid gland.
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The label A is for thyroid gland and the label B refers to trachea. The diagram represents the two parts. 
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Differentiate between.
Renin and rennin

Renin:
Renin produced in kidney helps in conversion of angiotensinogen into angiotensin which stimulates secretion of aldosterone for reabsorption. The mechanism is called renin-angiotensin mechanism.

Rennin:
Rennin acts as an enzyme that helps in digestion of milk protein.


Name the principal mineralocorticoid secreted by the adrenal cortex.

Mineralocorticoids are a class of corticosteroids, which are a class of steroid hormones secreted by Adrenal Medulla. Mineralocorticoids are corticosteroids that influence salt and water balances (electrolyte balance and fluid balance) by acting on renal tubules.


Match the terms:

Cushings syndrome,  Enzyme,  Acromegaly,  Endocrine,  Exocrine,  Diabetes Mellitus,  Diabetes Insipidus,  Myxedema,  Goiter,  Cretinism,  Hormone,  Enzyme

.......... producing secretions that are discharged directly into the blood stream.

An endocrine gland is a ductless gland that produces secretions that are discharged directly into the bloodstream. Their secretions are called hormones.


Why is pituitary glands called the master glands?

Pituitary gland is the main endocrine gland. It is called the master gland because it produces hormones that control other glands and other body functions including growth. It also controls hormone glands like thyroid, adrenals, ovaries and testicles. 


What do you understand by Adam's apple?

Adam's apple is the name given to the bulge of cartilage that covers the larynx. It is prominently visible in the neck region of males. In develops on the onset of puberty and results in hoarse voice in males. It occupies the position right at the top of the thyroid gland, so it is also called the thyroid cartilage.


Which hormone is released when someone has to fight?

The adrenal medulla secretes two hormones called adrenaline or epinephrine and noradrenaline or norepinephrine. Adrenaline and noradrenaline are rapidly secreted in response to the stress of any kind and during emergency situations like a fight. These hormones increase alertness, pupillary dilation, piloerection (raising of hairs), sweating etc. Both the hormones increase the heartbeat, the strength of heart contraction and the rate of respiration.


Prove that Pancreas is an endocrine as well as exocrine gland.

Pancreas act as an endocrine as well as an exocrine gland. It is considered as a mixed gland. 
Exocrine part of pancreas secretes digestive enzymes while, its endocrine part (islets of Langerhans) produce two hormones, i.e. insulin and glucagon. Only one per cent of the weight of the pancreas serves as an endocrine gland. The remaining 99 per cent of the gland has exocrine functions.


What is the emergency hormone?

Adrenaline is known as the emergency hormone because it is released by the adrenal glands under the conditions of stress or excitement. This hormone is also a part of the body’s stress response called the fight or flight response. Adrenaline performs various functions in the body like:
  • Increases the supply of oxygen and glucose to muscles and brain.
  • Increases the heart rate and the amount of blood pumped by the heart per beat.
  • Dilates the air passages and constricts the blood vessels.


Is the pancreas an exocrine or an endocrine gland?

  • The pancreas is considered as mixed gland as it acts as both exocrine and endocrine gland. 
  • As an exocrine gland, the pancreas secretes digestive enzymes into the pancreatic duct. 
  • Only about 1% of the total weight of pancreas acts as an endocrine gland. This portion of the pancreas is known as Islet of Langerhans which secretes insulin and glucagon.


Name the hormone which stimulates the entire sympathetic nervous system.

Norepinephrine which is chemically a catecholamine is release from adrenal gland is a neurotransmitter and responsible for the stimulation of sympathetic nervous system and directly stimulates adrenergic receptors.


Give example(s) of Androgens and estrogene.

Androgens and estrogens are hormones, androgen is responsible for the male features and reproduction whereas estrogens are important for sexual and reproductive development, mainly in women, they are also referred to as female sex hormones. Testosterone is the most important androgen for the physical changes that happen during male puberty, such as development of the penis and testes, and for the features typical of adult men such as facial and body hair. Testosterone also acts on cells in the testes to make sperm. Estradiol is considered as a type of estrogen. The ovaries, breasts, and adrenal glands make estradiol. During pregnancy, the placenta also makes estradiol. Estradiol helps with the growth and development of female sex organs, including the uterus.


Which gland is also called as 'Master gland '?

The pituitary gland is also called as master gland because it controls the functions of other endocrine glands by secreting specific hormones. 


Adrenalin hormone is secreted by which gland? 

Adrenalin is secreted by the Adrenal gland.


In the given diagram/figure label and give the properties of them
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1) Pituitary Gland: The pituitary gland is a tiny organ, the size of a pea, found at the base of the brain. As the “master gland” of the body, it produces many hormones that travel throughout the body, directing certain processes or stimulating other glands to produce other hormones.
2) Testes: they are the primary male reproductive organs. They fulfil two key functions, the production of gametes (sperm) and the secretion of hormones, particularly the male hormone testosterone.


Give the functions of testosterone.

Followings are the function of testosterone:
1. In males, testosterone directly increases size and mass of the muscles, bones, vocal cord.
2. It stimulates the growth of body hairs including abdominal, chest and pubic hair.
3. Enlargement of the larynx (Adam's apple) and deepening of the voice.
4. Broadening of shoulders and chest.
5. It helps in formation of sex organs in the fetus
6. Helps in growth of spermatogenic tissues in testicles and maintain male fertility.


Which hormone is responsible for the changes noticed in males at puberty?

Testosterone is responsible for the changes noticed in males at puberty. Testosterone is the primary male sex hormone it plays a vital role in the development of male reproductive tissue such as testes and prostate, as well as promoting secondary sexual characters such as the growth of body hair, bone mass, and increased muscles.


Write short on the functions of the parathyroid hormone.

The principal/chief cells of the parathyroid produce the parathyroid hormone also called the parathormone. The function of this hormone are as follows :
  • To maintain calcium and phosphate balance in the blood and other tissues.
  • To increase calcium reabsorption from the intestine as well as from the nephrons of the kidney.
  • To initiate bone resorption (e.g. reabsorption of calcium from bones), in case the blood calcium levels drop.


Write short on the functions of the testis.

The testis produces various male hormones collectively called as the androgens.
  • The androgens include; testosterone, dihydrotestosterone and androstenedione.
  • Testosterone is considered to be the primary hormone as it is produced abundantly when compared to others.
  • However, dihydrotestosterone is the more active form. The testosterone is ultimately converted to the active form in the target tissues.
  • Androgens regulate the development, maturation and function of the male sex organs (e.g. epididymis, seminal vesicles etc.,)
  • They play an important role in spermatogenesis and male sexual behaviour
  • They also promote protein and carbohydrate synthesis.


Give examples of hypercalcemic hormone.

The parathyroid hormone produced by the principal/chief cells of the parathyroid is a hypercalcemic hormone, It is also called the parathormone. The function of this hormone is to maintain calcium and phosphate balance in the blood and other tissues. It increases calcium reabsorption from the intestine as well as from the nephrons of the kidney. It also initiates bone resorption (e.g. reabsorption of calcium from bones), in case the of low blood calcium levels.


Write short note on the functions of the thyroid hormones.

The follicular cells of the thyroid gland synthesize two thyroid hormones; Tetraiodothyronine ( $$T_4$$-Thyroxine) and triiodothyronine ( $$T_3$$) and the C-cells of thyroid gland produces Thyrocalcitonin. The function of these hormones are as follows
  • Thyroxine is the main hormone (80% in thyroxine form) secreted into the bloodstream by the thyroid gland. 
  • It is the inactive form and most of it is converted to an active form called as triiodothyronine $$T_3$$ by organs such as the liver and kidneys.
  • Both  $$T_4$$ and  $$T_3$$ are synthesized from tyrosine and iodine.
  • The thyroid hormones control the metabolism of carbohydrates, protein and fats. They play an important role in regulating the Basal Metabolic Rate (BMR)
  • They are also important for maintenance of water and electrolyte balance. 
  • Thyroid hormones also regulate the RBC production.
  • The thyrocalcitonin maintains the blood calcium levels and promotes the bone formation.


Write short notes on the functions of the following hormones :
(a) Parathyroid hormone (PTH)
(b) Thyroid hormone
(c) Thymosins
(d) Androgens
(e) Estrogens
(f) Insulin and glucogon

(a) Parathyroid hormone 
The principal/chief cells of the parathyroid produce the parathyroid hormone, also called the parathormone. The function of this hormone is 
  • To maintain calcium and phosphate balance in the blood and other tissues.
  • To increase calcium reabsorption from the intestine as well as from the nephrons of the kidney
  • To initiate bone resorption (e.g. reabsorption of calcium from bones), in case the blood calcium levels drop.

(b) Thyroid hormone
Both the thyroid hormones T$$_4$$ (Thyroxine) and T$$_3$$ (active form) are secreted by the thyroid gland.
  • The thyroid hormones control the metabolism of carbohydrates, protein and fats. They play an important role in regulating the Basal Metabolic Rate (BMR)
  • They are also important for maintenance of water and electrolyte balance. 
  • Thyroid hormones also regulate the RBC production.
  • The thyrocalcitonin maintains the blood calcium levels and promotes the bone formation.

(C) Thymosins
The thymus actively secretes the hormones called thymosins (only till pre-pubescence)
  • The stimulation, development and differntiation of T-lymphocytes.
  • The development of cell-mediated immunity (T-lymphocytes mediated immunity)
  • The production of antibodies (Humoral immunity).

(d) Androgens
  • Androgens are the hormones which are responsible for the development of secondary sexual characters. The Leydig cells of testis produce androgens such as testosterone. 
  • Androgens are also produced by the adrenal cortex of the adrenal gland and the ovaries 

(e) Estrogens
  • In Non-pregnant females, they are predominantly secreted by the ovaries. However, during pregnancy, the placenta secretes a lot of estrogens.
  • The three types of estrogens are; $$\beta$$-estradiol, estrone and estriol.
  • The most active and the principal estrogen produced by the ovaries is the  $$\beta$$-estradiol. 
  • They play an important role in the growth and development of ovarian follicles and breast
  • They are responsible for the development of secondary sexual characteristics (e.g. high pitch voice)
  • They inhibit osteoclastic activity and stimulate bone growth. Osteoporosis in menopausal women is because of reduced estrogen levels.
They also influence the texture of the skin and female sexual behaviour

(f) Insulin and Glucagon
Glucagon
  • It increases the blood glucose levels by initiating glycogenolysis (glycogen degradation) and stimulating gluconeogenesis (synthesis of glucose from non-carbohydrate molecules) in the liver cells.
  • Since it increases the blood glucose levels it is a hyperglycemic (hyper-more, glycemic-sugar levels) hormone
  • It also initiates lipolysis (degradation of lipid) in the adipose tissue.
Insulin
  • It is released when the glucose level in the blood raises.
  • It lowers blood sugar levels in different ways; increasing the uptake of glucose by all the cells in the body, initiating glycogenesis (glycogen synthesis) in the liver and muscle.
  • It initiates lipogenesis (synthesis of lipids/fat) and storage of fat in adipose tissue and inhibits gluconeogenesis
  • It is a hypoglycemic (hypo=less) hormone as it reduces the sugar levels in the blood


List the hormone secreted by the atrium.

  • The atrial wall of the heart secretes a peptide hormone called the atrial natriuretic factor (ANF). 
  • It is released in response to stretching of the atrial walls. Its major function is to decrease blood pressure. 
  • It eliminates excess sodium ions from the body which decreases the blood volume (as more urine is produced) and thus reduces blood pressure.


Give the target gland for gonadotrophins (LH and FSH).

The target gland for gonadotropins (LH, FSH) is ovary and testis. In females, LH and FSH stimulate ovary to produce steroids. In males, LH stimulates Leydig cells to produce testosterone and FSH stimulates Sertoli cells to produce an androgen-binding protein (ABP), thereby stimulating spermatogenesis. 


List the hormones secreted by the adrenal gland.

The adrenal cortex and the adrenal medulla regions of the kidneys secrete several hormones that have a wide range functions in the body.
Hormones of the Adrenal Cortex
  • The hormones produced by the adrenal cortex are called the corticoids
  • Two types of corticoids are produced; Mineralocorticoids and the Glucocorticoids
  • Mineralocorticoids regulate water and electrolyte balance.
  • Glucocorticoids regulate the carbohydrate metabolism.
  • Aldosterone is the main mineralocorticoid produced by the adrenal cortex.
  • Aldosterone acts by stimulating the reabsorption of water and sodium and also causes excretion of potassium and phosphate ions. 
  • Cortisol, cortisone and corticosterone are the glucocorticoids produced by the adrenal cortex
  • Glucocorticoids control the blood glucose levels by stimulating gluconeogeneis, lipolysis and proteolysis. 
  • Cortisol also has anti-inflammatory activity and has the ability to suppress the immune response.
  • Androgens are also produced by the adrenal cortex and they are responsible for the growth of facial hair, pubic hair etc., 
Hormones of the Adrenal medulla
  • The medulla produces the catecholamines which include the hormones epinephrine (adrenaline) and norepinephrine (noradrenaline)
  • These are released under stress conditions and are called the emergency hormones or hormones of fight or flight.
  • Both the hormones stimulate glycogenolysis, lipolysis and proteolysis.
  • They increase the heartbeat and rate of respiration


List the hormones secreted by kidney.

The kidneys secrete 3 different types of hormones; erythropoietin, renin and calcitriol (1,25- dihydroxycholecalciferol). 
  • Erythropoietin and renin are peptide hormones secreted by the juxtaglomerular cells of the kidney
  • Calcitriol is a steroid hormone synthesized by the cells of the proximal tubules of the nephrons.
Erythropoietin
  • Its production is stimulated by hypoxia (insufficient oxygen supply to the tissues)
  • It stimulates the formation of RBC from the haematopoietic stem cells in the bone marrow.
Renin
  • Decreased blood pressure, low sodium levels are the stimuli for the production of renin from the kidney.
  • The renin secreted has enzymatic activity and is an important part of renin-angiotensin-aldosterone system (RAAS).
  • The RAAS plays an important role in regulating the cardiac output and arterial pressure.
  • The main function of renin in the RAAS system is the conversion of angiotensinogen to angiotensin I (proteolytic activity).
Calcitriol (1,25- dihydroxycholecalciferol)
  • It is the active form of vitamin D.
  • It stimulates the formation of calcium-binding protein thereby increasing the intestinal absorption of calcium.
  • Thus, it plays an important role in the mineralization of the bone (bone formation)


List the hormones secreted by ovary.

The ovaries secrete two types of female sex hormones called the estrogens and the progestins. 
Estrogens
  • In Non-pregnant females, they are predominantly secreted by the ovaries. However, during pregnancy, the placenta secretes a lot of estrogens.
  • The three types of estrogens are; ββ-estradiol, estrone and estriol.
  • The most active and the principal estrogen produced by the ovaries is the  ββ-estradiol. 
  • They play an important role in the growth and development of ovarian follicles and breast
  • They are responsible for the development of secondary sexual characteristics (e.g. high pitch voice)
  • They inhibit osteoclastic activity and stimulate bone growth. Osteoporosis in menopausal women is because of reduced estrogen levels.
  • They also influence the texture of the skin and female sexual behaviour
Progestins (Progesterone)
  • The progestins are secreted by the corpus luteum, a structure that is formed from the ruptured follicle (after ovulation/ later half of ovarian cycle).
  • Most important progestin is the progesterone. Small amounts of 17-αα-hydroxyprogesterone is also secreted along with progesterone.
  • Placenta also secretes large amounts of progesterone during pregnancy.
  • The progestins mainly have 2 functions; prepare the uterus for pregnancy and prepare breasts for lactation.
  • Progesterone acts on mammary glands and stimulates the formation of milk storing sacs called alveoli and milk secretion.


Give examples androgens and estrogens.

Androgens are male sex hormones that are responsible for the development of secondary sexual characters. Testosterone is an example of androgen, Estrogens are female sex hormones, an example of estrogen is estradiol. Testosterone is a hormone produced by the testis and is responsible for the proper development of male sexual characteristics. Estradiol is a female sex hormone produced by the ovaries, adrenal gland and also the placenta during pregnancy.


What are sex hormones? Why are they named so? State their function

Hormones that control the growth and development of secondary sexual characters are called as sex hormones. These hormones are produced in males and females under the influence of action of the pituitary gland.
Sex hormone in the male is testosterone and sex hormone in the female are oestrogens.
1. Testosterone: This hormone functions in male and brings about the growth and development of testes. This hormone is also responsible for the appearance of beard and hoarseness of voice.
2. Oestrogen: This hormone functions in female and is responsible for the development of secondary sexual characters, such as enlargement of breast and development of reproductive organs.


Give the function and source of insulin hormone?

Insulin is an essential hormone produced by the pancreas. Its main role is to control glucose levels in our bodies. Insulin is released into the bloodstream by specialised cells called beta-cells found in areas of the pancreas called islets of Langerhans.  It is a hormone essential for us to live and has many effects on the whole body, mainly in controlling how the body uses carbohydrate and fat found in food. Insulin allows cells in the muscles, liver and fat (adipose tissue) to take up sugar (glucose) that has been absorbed into the bloodstream from food. This provides energy to the cells. Insulin signals the liver to take up glucose and store it as glycogen. Insulin has several other metabolic functions like stopping the breakdown of protein and fat.


Give the exact location of the thyroid gland.

The thyroid gland is the largest endocrine gland.  It is located in the neck, just below the larynx and in front of the trachea. It produces two main hormones i.e., triiodothyronine and thyroxine.
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State the exact location of the following structures.
Thyroid gland.

Thyroid gland is a gland which is present in the neck. This is present in the front part of the neck and is located below the larynx. It is present along the tracheal pipe. The shape of this gland like the butterfly. There are lobules in this gland. There are follicle cells which produce the thyroid hormones. The thyroid hormones are responsible for regulating the metabolism of the body. 
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Explain the role of pancreas in digestion of various food materials.

Pancreas is an endocrine gland which produces hormones like insulin, glucagon, somatostatin. The pancreas is also a digestive organ. The pancreatic juice secreted by it contains digestive enzymes. These enzymes are involved in the digestion and absorption of nutrients in the small intestine. It secretes Trypsinogen, which is an inactive protease, pancreatic amylase and pancreatic lipase. These enzymes help to further break down the carbohydrates, proteins, and lipids. Protease enzymes are secreted by the stomach, pancreas and small intestine and they digest proteins. Carbohydrase enzymes (amylase) are secreted by the stomach, pancreas and small intestine and they digest complex starch (polysaccharide) molecules. Lipase is secreted by the pancreas and the walls of the small intestine. It digests complex fat (or lipid) molecules. 


(a) Draw a diagram indicating the position of four endocrine glands in human being.
(b) Write the function of insulin and thyroxine hormones in human being.

B) Insulin is responsible for regulation of the blood sugar level.
Thyroxine is responsible for maintenance of the basal metabolic rate. 

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Write an essay on endocrine function of gonads.

Gonads: 
Both tests and ovaries, in addition to their role as reproductive gamete producing organs, function as endocrine structures also.
Testis:
The testis contains epithelioid cells called the interstitial or Leydig cells. The Leydig cells secrete the androgenic hormone testosterone.
Action of testosterone:
1. Testosterone causes the embryonic development of male reproductive organs.
2. It promotes the development of the secondary sexual characters of males.
Ovary:
The ovaries are responsible for the production of oestrogen, progesterone and testosterone. 
Action of hormones:
1. Testosterone is involved in the development of body mass and bone strength in the case of females.
2. Oesterogen is responsible for the development of secondary sexual characters in females. 
3. Progesterone is responsible for maintaining pregnancy and lactation. 


What is erythropoietin? What is its function?

  • Erythropoietin is a hormone that is secreted by the cells of the kidney. The main function of the hormone is the production of red blood cells. 
  • The hormone stimulates the cells of the bone marrow to start the process of red blood cell formation which is also known as erythropoiesis. 
  • The hormone also regulates the differentiation of the red blood cells. This process helps to initiate the formation of hemoglobin.


The human sperm consist of head, middle piece and tail. What purpose does the tail in a sperm serve?

In sperm, the tail acts as a propulsion system. It helps the sperm to swim in the female reproductive tract to reach and fertilize the ovum. 
669872_616050_ans_d8e959764d6f426dbe65bd1d6abb9272.jpg


The quantity of urine excreted by a person in different seasons is given below. Analyse it and answer the following question.
Season 1Season 2Season 3Season 4
1.5 litre/day1.4 litre/day1.9 litre/day1.8 litre/day
(a) Which is the coldest season?

(a) Season 3. In cold season less water is lost by the body through sweat because of the lesser heat. This water is lost through urine. So, the urine output increases during the cold season.


Name the male and female sex hormones. List out their functions.

Estrogen and testosterone are the female and male sex hormones respectively.
  • Estrogen helps in the maturation of the eggs and plays and affects fallopian tubes, vagina, uterus, etc. 
  • Testosterone helps in the development of prostate and testes. It also affects muscular development and body hair.


Match the names of Endocrine glands given in Column 'A' with their functions and symptoms of disorders given in Column 'B'.

  • A- 3: Antidiuretic hormone which is secreted by the hypothalamus and released by the posterior part of the pituitary gland causes excretion of water from the kidneys. The deficiency or the disorder prognathism may result in protruded jaws, excessive urination, and thirst.
  • B- 5: The thyroid gland is responsible for the secretion of the thyroxine which is responsible for growth and development. The deficiency or disorder of the hormone may result in protrusion of the tongue, tiredness, fatigue, and a decrease in the metabolic rate.
  • C- 6: The parathyroid gland is responsible for parathormone which regulates the level of calcium in the blood and the uptake by the bones. The deficiency of this syndrome may cause loss of calcium ions from the bones. This will result in the state called soft bones which can be easily damaged by fractures. 
  • D- 1: The ovary releases progesterone which causes the uterus to prepare for implantation. The cell lining of the endometrium thickens and if the egg is fertilized the zygote is implanted in the uterus. The disorder related to this hormone may cause an irregular menstrual cycle. 


Changes in the amount of hormones produced will affect our bodily activities.
Write down the changes that occur in our body by the increase and decrease of the hormones given below.
(a) Parathermone.
(b) Vasopressin.

(a) Parathormone:
1)  Its over secretion leads to increase in blood calcium level.
This may lead to kidney stones and fragile bones.
 2) Its under secretion leads to decrease in blood calcium level. This results in tetany that increases contraction of muscles. 
(b) Vasopressin:
1) Its over secretion decreases the quantity of urine and it is more concentrated
2) Its under secretion leads to increase in thirst and the person drinks a lot of water. Hence frequent urination is seen and the person suffers from diabetes insipidus.


Which hormone is commonly known as fight and flight hormone?

Adrenaline is a natural hormone that is produced by the body and secreted throughout the body and helps in regulation of sympathetic and parasympathetic response. It causes an increase in blood pressure, increased breathing, boosting up of energy, etc. This hormone is also called as fight and flight hormone.


What are sex hormones? Describe any one male and one female sex hormones.

Hormones which control processes related to sexual reproduction and development of secondary sexual characters in animals including man are called sex hormones. These are produced by gonads. Testes produce androgens mainly testosterone and ovary produces estrogen, progesterone, and relaxin. Adrenal cortex also produces some sex hormones especially androgens. 
(i) Progesterone: This .female sex hormone is secreted by corpus luteum. It helps in implantation of fertilized egg in uterus, maintenance of pregnancy, therefore, it is called pregnancy hormone. 
(ii) Testosterone: This male sex hormone is secreted by Leydig's cells of testes. It promotes development of secondary sexual characters in males, stimulates the growth of seminal vesicle, prostrate, vasa deferense etc. It helps in development of muscles. It also stimulates formation of sperms.


The name of largest endocrine gland of our body is 

The thyroid gland is the largest endocrine gland of the human body. It is a bilobed gland connected by an isthmus. It is located at the front of the neck, below Adam's apple. Triiodothyronine (T3) and thyroxine (T4) are the two hormones which help to increase the metabolic rate and accelerate the process of protein synthesis. The TSH hormones secreted by the anterior pituitary regulates its function.


In lactating mothers, a hormone helps to bring the uterus back to the original state. 
(a) Which is this hormone?
(b) Note down another function of this hormone.

(a) The hormone is oxytocin. It helps is parturition.
(b) Oxytocin also stimulates the ejection of milk from the mammary glands in lactating mothers. This is called milk ejection reflex.


Name any one heterocrine gland?

Heterocrine glands are those glands which have both exocrine and endocrine part. The pancreas is called a heterocrine gland because it secretes the hormone insulin into the blood which is an endocrine function and enzymes into the digestive tract which is an exocrine function.


Write short notes on the functions of the hormone Thymosin.

Thymus secretes hormone called thymosin and it stimulates the development of disease fighting T cells which help to keep us healthy by attacking virus-infected or cancerous cells. The thymus serves a vital role in the training and development of T-lymphocytes or T cells. T cells defend the body from deadly pathogens such as bacteria, viruses, and fungi. 


List the hormones secreted by the Pituitary.

Pituitary gland is also called as hypohysis. Hormones secreted by the pituitary gland is helps in growth, blood pressure, certain functions of sex organs, thyroid glands and metabolism as well as some aspects of pregnancy, child birth etc... The pituitary gland has two parts—the anterior lobe (adenohypophysis) and posterior lobe (neurohypophysis)—that have two very separate functions. Hormones secreted by the adenohypophysis are Growth hormone (GH), Prolactin, Thyroid-stimulating hormone (TSH), Adrenocorticotrophic hormone (ACTH), Luteinizing hormone (LH), Follicle-stimulating hormone (FSH) and Melanocyte-stimulating hormone (MSH). Hormones secreted by the neurohypophysis are Oxytocin (Birth Hormone) and Vasopressin [Anti-diuretic Hormone(ADH)].


List the hormones secreted by Atrium.

Atrium is the upper chamber of the heart through which the blood enters. There are two atria in the human heart. Atrial natriuretic factor (ANF) is the hormone produced by the right atrium of the heart. These natriuretic factors are of special interest both physiologically and clinically, because they participate in the regulation of cadiovascular and renal homeostatic mechanisms. They are involved in the regulation of body fluid volume and electrolyte balance.


Write short notes on the functions of the Parathyroid hormone (PTH).

Humans have four parathyroid glands, which are small glands in the neck, located behind the thyroid gland. These glands secrete parathyroid hormone (PTH, also known as parathormone). Parathyroid hormone regulates calcium and potassium levels in the blood, which is necessary for nervous and muscular systems to function properly. When the calcium in the blood goes too low, the parathyroid glands make more PTH. PTH raises the blood calcium level by desorption of the bones.


Give example(s) of Gonadotrophic hormone.

Gonadotropins are hormones that stimulate the gonads, or sex glands, to carry out their reproductive or endocrine functions. In males, these glands are the testes, and in females the ovaries. Gonadotropins are glycoprotein polypeptide hormones. Deficiency due to pituitary disease results in hypogonadism which can lead to infertility. The major gonadotropins are follicle stimulating hormone (FSH) and luteinizing hormone (LH). FSH is responsible for growth and development of follicles in the ovaries and stimulates these cells to secrete estrogen. In males, it stimulates the production of sperm cells at puberty. Function of LH in females triggers ovulation and development of the corpus luteum. In males, where LH had also been called interstitial cell–stimulating hormone (ICSH), it stimulates Leydig cell production of testosterone.


List the hormones secreted by the Kidney.

The kidneys are small bean-shaped organs and consist of two main layers, an inner layer called the medulla and an outer layer called the cortex. They help control the chemical balance of the blood and regulate the body's level of sodium, potassium and calcium. The kidneys make two main hormones, vitamin D and erythropoietin. Vitamin D is essential for a number of different functions in the body. Active vitamin D stimulates the uptake of calcium from food, is important for the maintenance of healthy bones and also helps to regulate the response of the immune system to infection. Erythropoietin is produced when oxygen levels in the blood are low. It acts in bone marrow to stimulate the production of mature red blood cells, to maintain healthy oxygen levels in our tissues.


List the hormones secreted by Parathyroid.

Humans have four parathyroid glands, which are of small glands in the neck, located behind the thyroid gland. These gland secretes parathyroid hormone (PTH, also known as parathormone). Parathyroid hormone regulates calcium and potassium levels in the blood, it is maintained because nervous and muscular systems has to function properly.


List the hormones secreted by Thymus.

The thymus gland secretes hormone called thymosin and it stimulates the development of disease fighting T cells which help to keep us healthy by attacking virus-infected or cancerous cells. The thymus serves a vital role in the training and development of T-lymphocytes or T cells. T cells defend the body from deadly pathogens such as bacteria, viruses, and fungi. 


The diagram given below represents the location and structure of an endocrine gland. Study the same and answer the questions that follow:
Name the endocrine gland shown in the diagram.
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The given diagram is that of thyroid gland which is the largest endocrine gland in the human body. The thyroid gland surrounds the front of the larynx and upper part of trachea in the neck. It is a bilobed, highly vascular organ. The two lobes are connected by a narrow band, the isthmus. It is composed of rounded follicles held together by loose connective tissue, the stroma and enclosed by a thin fibroelastic capsule. The thyroid gland is endodermal in origin. In adult human beings, the thyroid gland measures 5cm in length and 3 cm in width. Its average weight is 25 gms. It is somewhat larger in women. The gland is divided internal into large number of lobules by thin septa. The wall of each thyroid consists of a single layered cuboidal epithelium suspended from a basal lamina.



What is the technical term for the cells of the pancreas that produce endocrine hormones?

Pancreas is an endocrine gland. It secretes two types of endocrine hormones, namely insulin and glucagon. Insulin is secreted by the beta cells of the islets of Langerhans of pancreas. Glucagon is secreted by the alpha cells of the islets of Langerhans of pancreas. Insulin decreases the blood glucose level when there is high amount of sugar present in the blood. Glucagon releases glucose from the liver in the blood when there is low levels of sugar present in the blood. 


Given alongside is a portion from the human body showing some important structure in ventral (front) view.
Name the structures numbered 1-3.

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1 - Larynx
2 - Thyroid gland
3 - Trachea. 


Why is the pancreas referred to as an exo-endocrine gland?

Exocrine glands are those glands which deliver their secretions to the target through ducts. Exocrine glands mainly secrete digestive juices or enzymes of various kind. Endocrine glands are those glands which release their secretions directly into the blood which carries it to the target sites. Endocrine glands mainly secrete hormones. Since pancreas secretes both digestive juices and hormones and has exocrine and endocrine parts, it is known as an exo- endocrine gland.


Why pituitary gland is called "master gland" ? 

  • The pituitary gland is the main endocrine gland.
  •  It is a small structure in the head. It is called the master gland because it produces hormones that control other glands and many body functions including growth. 
  • The pituitary consists of the anterior and posterior pituitary. Hence, the pituitary gland is called the master gland.



Very short answer type.
Write an example each of a apocrine gland, holocrine gland and merocrine gland.

The mammary gland is an apocrine gland, sebaceous (oil) gland is a holocrine gland, and the salivary gland is a merocrine gland.


Fill in the blanks with appropriate words.
The blood sugar level is controlled by two organs the.......... which releases glucose into the blood, and the.......... which releases the hormone ..........that allows glucose to move from the blood to the interiors of cells.

The blood sugar level is determined by the amount of glucose present per unit volume of blood. This is controlled by two factors: the amount of glucose that the liver releases into the blood and insulin released by the pancreas that facilitates movement of glucose into the cells.


Very short answer type.
Mark the odd one in each series.
salivary gland, thyroid gland, gastric gland, tear gland

The thyroid gland is the odd one out because it is an endocrine gland that secretes thyroid hormones. The rest of the options are exocrine glands that give out secretions.


Fill in the blanks with approriate words.

The anterior pituitary has been called master gland, because of the tropic hormones it releases. The real master gland, however, is ......... because its ......... hormones regulate the secretory activity of the anterior pituitary.

Hypothalamus, Releasing


Very short answer type.
Substance T is present in the urine. Does this prove that it is filterable at the glonierulus?

It is possible that a substance present in the urine is filtrable at the glomerulus, however, tubular secretions also take place in nephrons during the formation of urine. So it may also have been secreted by renal tubules into the urine that is formed.


Fill in the blanks with appropriate words.
The gland which grows to its maximum size at puberty and then diminishes gradually is .........

The thymus produces essential immune cells called T cells, which are continuously lost and must be replaced throughout life. But starting around the time of puberty, the thymus rapidly decreases in size and loses its capacity to produce enough new T cells.


Name the hormone that regulates the rise in calcium ion level in the blood.

Parathyroid hormone (PTH) increases the Ca$$^{2+}$$levels in the blood. PTH acts on bones and stimulates the process of bone resorption (dissolution/demineralisation). PTH also stimulates reabsorption of Ca$$^{2+}$$ by the renal tubules and increases Ca2+ absorption from the digested food. Hence, PTH is a hypercalcemic hormone, i.e., it increases the blood Ca$$^{2+}$$ levels.


Name the endocrine gland that secretes norepinephrine.

Adrenal gland secretes norepinephrine.
The adrenal medulla secretes epinephrine and norepinephrine. These are commonly called catecholamines. They are rapidly secreted in response to the stress of any kind and during emergency situations and are called emergency hormones or hormones of Fight or Flight.


Very short answer type.
Name the endocrine gland that secretes glucagon.

Glucagon is secreted by islets of Langerhans of the pancreas. Glucagon is a hormone that regulates blood glucose level through glycogen breakdown.


Very short answer type.
Name the hormones released by the posterior pituitary

Vasopressin and oxytocin are released by the posterior pituitary. Vasopressin controls the amount of water excreted through urine and oxytocin plays a role in female reproduction and childbirth.


Differentiate between estrogens and progesterone.

$$\textbf{Solution}$$ 

 $$\textbf{S.No.}$$$$\textbf{Estrogen}$$  $$\textbf{Progesterone}$$
1Steroid hormone is produced by the graffian follicle.  Steroid hormone is produced by the corpus luteum. 
2 FSH regulates its secretion.  LH regulates its secretion. 
3  Helps in the development of secondary sexual characters.  Helps in the development of the uterus layer i.e. endometrium for the implantation of the embryo. 




Describe the structures arid functions of glucocorticoids.

Glucocorticoids are steroids chemically. Cortisol is an example of glucocorticoid. Given the diagram shows the structure of cortisol. 
Glucocorticoids stimulate gluconeogenesis, lipolysis and proteolysis and inhibit cellular uptake and utilisation of amino acids. Cortisol is also involved in maintaining the cardiovascular system as well as the kidney functions. Glucocorticoids, particularly cortisol, produces anti-inflammatory reactions and suppresses the immune response.


The pituitary gland is often referred to as the middleman in endocrine functions. Explain, why it is described in this way.

The pituitary gland is considered as master Gland. It controls growth & activity of the Thyroid Gland, Adrenal Gland, Gonads, & Liver. It is considered “Middleman” between the brain (CNS) and the peripheral endocrine organs. As it receives releasing/inhibiting hormones from the hypothalamus that regulates the release of pituitary hormones. Pituitary hormones in turn act on endocrine and non-endocrine tissue for various physiological functions in the body. 


The pituitary is the master of an endocrine orchestra. Discuss.

The pituitary gland, also known as hypophysis, is about the size of a pea and is located in the centre of the brain, just below the hypothalamus. It has three lobes that secrete various hormones. The secretions of pituitary glands affect growth, metabolism, sexual development and system of reproduction. These hormones actively control the activity of other endocrine glands and hence known as the master gland.


Enlist the hormones secreted by the pancreas. Explain the functions and regulation of the secretion of insulin.

Following hormones are secreted by pancreas:-
  1. Insulin
  2. Glucagon
  3. Somatostatin. 

Insulin is an anti glycemic hormone i.e. it decreases blood glucose level. Insulin acts mainly on hepatocytes and adipocytes (cells of adipose tissue) and enhances cellular glucose uptake and utilisation. As a result, there is a rapid movement of glucose from the blood to hepatocytes and adipocytes resulting in decreased blood glucose levels (hypoglycemia). Insulin also stimulates the conversion of glucose to glycogen (glycogenesis) in the target cells. 
The pancreas produces hormones in its 'endocrine' cells. These cells are gathered in clusters known as islets of Langerhans. These cells monitor what is happening in the blood so that they can release hormones directly into the blood when necessary. In particular, they sense when sugar (glucose) levels in the blood rise, and as soon as this happens the cells produce hormones, particularly insulin. Insulin then helps the body to lower blood glucose levels and 'store' the sugar away in fat, muscle, liver and other body tissues where it can be used for energy when required.


Very short answer type.
Name the source gland and give one main action of the following hormones:
Glucocorticoids.

Glucocorticoids are secreted by zona fasciculata of the adrenal cortex. It is associated with carbohydrate, lipid, protein and purine metabolism.


Name the principal mineralocorticoid secreted by the adrenal cortex. What stimulates its secretion? Give its any two functions. What is the disorder caused due to excessive secretion of this hormone?

Aldosterone is principle mineralocorticoid secreted by the adrenal cortex. Serum potassium concentrations are the most potent stimulator of aldosterone secretion.  A fall in glomerular blood flow/glomerular blood pressure/GFR can activate the JG cells to release renin which converts angiotensinogen in blood to angiotensin I and further to angiotensin II. Angiotensin II activates the adrenal cortex to release Aldosterone.
Following are functions of Aldosterone:-
  1. Acts mainly at the renal tubules and stimulates the reabsorption of Na+ and water. 
  2. Excretion of K+ and phosphate ions. 
Hyperaldosteronism is a disorder characterized by excessive secretion of aldosterone, which causes increases in sodium reabsorption and loss of potassium and hydrogen ions.


Short / Long answer type questions.
Adrenaline is called an emergency hormone. Justify.

Adrenaline is known as the emergency hormone because it is released by the adrenal glands under the conditions of stress or excitement. This hormone is also a part of the body’s stress response called the fight or flight response. Adrenaline performs various functions in the body like:
  • Increases the supply of oxygen and glucose to muscles and brain.
  • Increases the heart rate and the amount of blood pumped by the heart per beat
  • Dilates the air passages and constricts the blood vessels


Differentiate between vasopressin and oxytocin.

 Vasopressin Oxytocin
Vasopressin is biosynthesized mainly in the supraoptic nuclei of the hypothalamusOxytocin is biosynthesized mainly in paraventricular nuclei of the hypothalamus
It helps to conserve water in the body.
It causes contraction of the uterine muscles during childbirth.


Match the terms to these definitions:
Cushings syndrome,  enzyme,  acromegaly,  endocrine,  exocrine,  diabetes mellitus,  diabetes insipidus,  myxedema,  goiter,  cretinism,  hormone,  enzyme
.......... A disorder of the pituitary gland characterized by intense thirst and by the excretion of large amounts of urine.

Deficiency of ADH or vasopressin leads to a disorder of pituitary gland characterized by intense thirst and excretion of large amounts of urine. Such a condition is called diabetes insipidus.


Differentiate between glucocorticoids and mineralocorticoids. (any two)

 Glucocorticoids Mineralocorticoids
Glucocorticoids are steroid hormones secreted by the cells of zona fasciculata of the adrenal cortex.Mineralocorticoids are steroid hormones secreted by the cells of the zona glomerulosa of the adrenal cortex.
They play an important role in carbohydrate, lipid, protein, and purine metabolism.Their main function is to regulate the plasma sodium and potassium concentrations.


Write short note on thymus gland.

Thymus gland is a type of endrocrine gland that located behind the sternum. It is also called as lymphoid organ as it involves in the maturation of T lymphocyte.  It secretes hormone thymosin. Thymosin plays an important role in the maturation of T cells. It is active till puberty and after that it starts shrinking and later replaced by fat.


Name the functions of corpus luteum.

Corpus luteum secretes progesterone, relaxin, inhibin/actin hormones. Progesterone stimulates the uterine glands to produce increased amounts of watery fluids. It also increases endometrium of the uterus. It also maintains pregnancy (placenta formation). Relaxin increases the flexibility of the pubis symphysis of the pelvic girdle at the time of child birth. Inhibin inhibits and actin activates the FSH and GnRH production.


Name the glands which secretes the following hormone.
Melatonin

Melatonin is a hormone produced by the pineal gland which regulates diurnal rhythm of our body. It helps maintaining the normal rhythms of sleep- wake cycle, body temperature and also influences metabolism, pigmentation, menstrual cycle and our defense capability. 


Explain the origin and location of pituitary gland.

  1. The pituitary gland is a master gland present at the base of the brain.
  2. It develops from the ectoderm layer of the embryo.
  3. It is located below the hypothalamus in a bony cavity called sella turcica (small depression in the sphenoid bone).


Thyroid is located close to ............ (larynx/ kidney).

Thyroid gland secretes thyroxin hormone and is located close to larynx (voice box) as shown in the diagram.
So, the correct answer is 'Larynx'.

956415_1045271_ans_82b0dd13286e4908962a61234b501323.jpg


One of the effects of increased secretion of adrenaline is .......... (Dry mouth/slowing of heartbeat/face flushed with blood).

Adrenaline is secreted from the adrenal cortex and is known as emergency hormone. It is associated with regulating the potential for conditions needed for fight or flight. When the body is under stress, homeostasis is disturbed and this immediate response is described as preparing the body for 'fight or flight'. It increases alertness, pupillary dilation, raising of hairs or piloerection, mouth becomes dry because the secretion of gastric juices is decreased as the blood flow to the digestive system is also decreased.
So, the correct answer is 'Dry mouth'.


Give an account on secretions of pituitary gland.

The pituitary gland is present near the hypothalamus of the forebrain, occupying the underside of the brain. It is connected with the hypothalamus by the stalk-like structure called the infundibulum. The pituitary can be divided into lobes called the anterior lobe and the posterior lobe. The anterior lobe is also called adenohypophysis and it receives the inhibiting or stimulating hormones from the hypothalamus via the portal blood vessels and secretes the hormones accordingly. The posterior pituitary also called the neurohypophysis does not secrete its own hormones but receives and stores the hormones of the hypothalamus. The hormones secreted by the adenohypophysis are as follows:
1. Growth Hormone- works on different organs of the body and regulates growth.
2. Thyroid Stimulating Hormone- regulates the release of hormones from the thyroid gland.
3. Adrenocorticotropic Hormone- regulates the release of adrenal gland hormones.
4. Follicle Stimulating Hormone- regulates follicle growth in ovaries of female and spermatogenesis in males.
5. Leutinizing Hormone- regulates the secretion of estrogen by the ovaries in females and the testosterone by the testes in males.
6. Prolactin- stimulates the mammary glands to produce milk during the pregnancy.
7. Melanocyte Stimulating Hormone- Stimulate the melanocytes to produce the pigmentation. 
The hormones stored and then released by the posterior pituitary are as follows:
1. Oxytocin-  it regulates the contraction of the muscles during the childbirth and stimulates the secretion of milk from the mammary glands. 
2. Anti-diuretic hormone or vasopressin- it prevents the loss of water and maintains the blood pressure.



What is pituitary gland? What is its function ?

The pituitary gland is the master endocrine gland located between the hypothalamus and the pineal gland in a depression called sella turcica in the sphenoid bone. The pituitary gland has two parts: The anterior pituitary which produces hormones that affect the breasts, adrenal glands, thyroid, ovaries and testes etc. The posterior pituitary stores and releases hormones synthesized by the hypothalamus which predominantly act on kidneys, uterus etc.


Explain the process which takes place when a hormone binds the receptors.

When a hormone binds to the receptors, it causes the cascade of reactions. The lipid-soluble hormones diffuse through the plasma membrane and then bind to a receptor protein. The water-soluble hormones bind to a receptor protein on the plasma membrane. Due to binding of hormones to the receptors, the G protein present on the plasma membrane gets activated. This then activates adenylyl cyclase. This enzyme converts ATP into cyclic AMP (cAMP). A cAMP is the secondary messenger. It further activates protein kinase enzyme. This enzyme then activates phosphorylation of the protein in the cytoplasm and the cell activity is altered. 
969814_1050220_ans_76d195988d8e4bc5a66e6717654e84c0.jpg


Name the hormones produced by kidney.

Hormones produced by kidney are erythropoietin, calcitriol, renin. Erythropoietin increases the RBC production. Calcitriol regulates the levels calcium and phosphorus in the body. Renin regulates blood pressure and fluid balance in the body.


The other name for pancreas is .............

Pancreas is also known as mixed gland because it is both endocrine and exocrine in nature. The islets of Langerhans functions as endocrine cells and secretes into the blood several important hormones, including insulin, glucagon, somatostatin, and pancreatic polypeptide. While the acini cells function as exocrine cells and secretes pancreatic juice into the duodenum through the pancreatic duct.


What are the functions of pancreas in the human body? 

Pancreas is an organ in the digestive system and produces insulin and other important enzymes and hormones that help break down food materials.



Write an account of position, structure and functions of pituitary gland.

POSITION: The pituitary gland is situated at the base of the skull just below the hypothalamus of the fore-brain. 
STRUCTURE: The pituitary gland is made up of three lobes as the anterior pituitary (adenohypophysis), the middle pituitary, and the posterior pituitary (neurohypophysis). The anterior pituitary receives the stimulating or the inhibiting hormones from the hypothalamus via the portal vein system and it secretes the hormones accordingly. The posterior pituitary does not release its hormone. It stores the hormones secreted by the secretory neurons of the hypothalamus and stores them.
FUNCTION: 
The hormones secreted by the anterior pituitary are as follows:
1. Growth hormone or somatotropin: it regulates the growth of the body protein anabolism.
2. Thyroid stimulating hormone (TSH): it controls the secretions of the thyroid gland.
3. Adrenocorticotropic hormone (ACTH): it regulates the hormone secretion from the adrenal cortex.
4. Follicle stimulating hormone: it stimulates spermatogenesis in males and ovarian follicle growth in females.
5. Leutinizing hormone: it stimulates secretion of progesterone from the corpus luteum is females and testosterone from the Leydig's cells in males.
6. Prolactin: It controls the growth of mammary glands and stimulates milk production.
The middle pituitary secretes melanocyte stimulating hormone (MSH) that controls pigmentation.
The posterior pituitary stores the oxytocin and anti-diuretic hormone (vasopressin) that are secreted from the hypothalamus and make them release into the bloodstream. The oxytocin stimulates the contraction of uterine muscles during the childbirth and stimulates secretion of milk from the mammary glands. Vasopressin stimulates reabsorption of water in the distal convoluted tubule of the kidney and prevents loss of water from the body.


Give an account of position , structure and action of pituitary gland.

  • Position and structure-This gland are lies in a cavity named sella tursica and attached by a stalk to the Hypothalamus. It has two parts into Adenohypophysis and Neurophysics. Adenophysis has two portions pars distal and pars intermedia.
  • Fuction- pars distal secretes six hormone named Growth hormone(GH),Prolactin,Thyroid stimulatin hormone(TSH),Adrenocorticotrophic hormone(Acth),lutenizing hormone (LH),and Follicle stimulatin hormone(FSH)
Pars intermedia secretes one hormone Melanotropic stimulating hormone(MSH)


State the role of pancreatic juice in digestion of proteins.

Pancreatic juice contains a variety of inactive enzymes such as trypsinogen, chymotrypsinogen, and carboxypeptidases. These enzymes play an important role in the digestion of proteins.
Physiology of protein digestion
The enzyme enterokinase is secreted by the intestinal mucosa. It activates trypsinogen into trypsin.
Trypsin then activates the other enzymes of pancreatic juice such as chymotrypsinogen and carboxypeptidase.
Chymotrypsinogen is a milk-coagulating enzyme that converts proteins into peptides. 
Carboxypeptidase acts on the carboxyl end of the peptide chain and helps release the last amino acids. Hence, it helps in the digestion of proteins. 
Thus, in short, we can say that the partially hydrolysed proteins present in the chyme are acted upon by various proteolytic enzymes of the pancreatic juice for their complete digestion.


Write short notes on the functions of androgens.

Androgens  are the hormones which is responsible for development of secondary sexual characters. The leydig cells of testis produce androgens such as testosterone. Testosterone is a male sex hormone that regulates the development of secondary sex characteristics such as facial hair, hoarse voice, development of reproductive organ, etc. Androgens also regulate the development, maturation, and functions of various male accessory organs such as epididymis and prostate glands. It stimulates spermatogenesis and formation of mature sperms. It also influences male sexual behaviour.


Cortisone, Somatotropin, Adrenocorticotropic hormone,
Vasopressin.

Odd term: Cortisone
Category: Hormones of pituitary gland
Somatotropin and adrenocorticotropic hormone are the tropic hormones secreted by anterior pituitary while vasopressin is released in blood by posterior pituitary. Cortisone is the hormone secreted by adrenal cortex. 


Complete the following paragraph by filling in the blanks (i) to (v) with appropriate words.
The amount of urine output is under the regulation of a hormone called (i) ______ secreted by the (ii) ______ lobe of the pituitary gland. If this hormone secretion is reduced, there is an increased production of urine. This disorder is called (iii) ______. Sometimes excess glucose is passed with urine due to hyposecretion of another hormone called (iv) ______ leading to the cause of a disease called (v) ________.

An antidiuretic hormone secreted by the of the posterior lobe of the pituitary that regulates the urine output. The inability of the neurohypophysial system to produce ADH causes excess urine production with resultant ion loss from blood called as diabetes insipidus. The presence of high amount of sugar in the urine is an indicator of the inability of individual to metabolize/take up sugar due to hyposecretion of insulin and the condition is called as diabetes mellitus. 


Write short notes on the functions of Insulin and Glucagon.

$$\textbf{Solution:}$$

$$\bullet$$ The endocrine part of the pancreas is an aggregation of cells known as islets of Langerhans which consists of four types of cells that secrete four types of hormones;alpha cells secretes glucagon,beta secretes insulin,delta cells secretes somatostatin and f cells secrete pancreatic polypeptide.

$$\textbf{Glucagon:}$$
$$\bullet$$ Glucagon is secreted from the alpha cells of islets of llangerhans which increases the oxidation of glycogen into glucose when glucose level falls in the body. It is a catabolic hormone ,which promotes breakdown of proteins and oxidation of fat to produce glucose as final products .Glucagon acts on the cells of liver and adipose tissue.
$$\textbf{Insulin:}$$
$$\bullet$$ Insulin converts glucose into glycogen when glucose levels increase in the body. It is an anabolic hormone ,which increases protein synthesis from amino acids and reduces breakdown and oxidation of fatty acids.Thus insulin and glucagon are also called antagonistic hormones.


Name two hormones secreted by pancreas. Write one function of each.

The endocrine cells of the pancreas are known as islets of Langerhans, which composed of two primary types of cells, alpha cells, which secrete glucagon and beta cells, which secrete insulin.
  • The function of glucagon: 
Chemoreceptors in the alpha cells detect decreased blood glucose levels and release glucose into the blood. Glucagon facilitates the breakdown of nutrients and their release into the blood.
  • The function of Insulin: 
Chemoreceptors in the beta cells detect an increase in blood glucose and stimulate to release insulin. It decreases the level of nutrients within the blood.


Describe the hormonal feedback circuits involed in controlling renal functions.

Regulation of kidney function involves feedback circuits.
There are 3 main feedback systems that regulate the kidney functions. 
1. Control by JGA:
JGA operates multihormonal Renin-angiotensin-aldosterone system  (RAAS).  The JGA responds to a decrease in blood pressure or blood volume in the afferent arteriole of the glomerulus and releases an enzyme, renin, into the bloodstream. In the blood, renin initiates chemical reactions that convert a plasma protein called angiotensinogen to a peptide called angiotensin $$I$$. This is converted to angiotensin $$II$$ in lungs by angiotensin converting enzyme. Angiotensin $$II$$ acts on adrenal gland and results in the release of aldosterone from the adrenal gland. Aldosterone increases blood pressure and increases blood flow to the glomerulus. It acts on DCT and collecting duct and increases reabsorption of Na+. 

2. Control by ADH:
ADH is released from pituitary gland when osmolarity of blood is increased. It acts on DCT and collecting duct and helps in reabsorption of water. 

3. Control by ANF
Atrial Natriuretic Peptides (ANF)  opposes the regulation by RAAS.  ANF inhibits the release of renin from the JGA and thereby inhibits NaCl reabsorption by collecting duct and reduces aldosterone release from the adrenal gland. 


Very short answer type.
What type of epithelium forms the parietal layer of the glomerular capsule, the proximal convoluted tubule, and the distal convoluted tubule?

Simple squamous epithelium forms the parietal layer of the glomerular capsule because it allows passage of small molecules through the membrane.
Simple cuboidal epithelium with numerous microvilli is present in the proximal convoluted tubule.
Simple cuboidal epithelium with few microvilli is present in the distal convoluted tubule.


Very short answer type.
Suppose a calculus (stone) is blocking a major calyx, what effect might this have on capsular hydrostatic pressure (ClIP) and thus on net filtration pressure (NFP)? 

If a stone or calculus is blocking a major calyx, it will increase the capsular hydrostatic pressure and thus, there will be a decrease in net filtration pressure. The resistance caused by the stone increases C1IP. Net filtration pressure decreases across glomerulus because the net passage of filtrate will be lesser due to the blockage.


Study the diagram given and then answer the questions with reference to the endocrine function of that gland.
State the main function of (1) glucagon and (2) insulin.

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Pancreas is an endocrine gland. It secretes two types of hormones, namely insulin and glucagon. 
Function of 
1. Glucagon releases glucose from the liver in the blood when there is low levels of sugar present in the blood. 
2. Insulin decreases the blood glucose level when there is high amount of sugar present in the blood. These both hormones are secreted in response to blood sugar levels. 


Fill in the blanks with approriate words.
Thymus gland synthesizes ......... and ......... hormones.

Thymus gland synthesizes thymosin and thymopoietin hormones. Thymus gland is an endocrine as well as immune gland at the same time. Thymus gland hormones regulate production of blood cells like lymphocytes. They also regulate metabolism of different macronutrients, development of musculoskeletal system and immune response in the body until the age of 15 years.


Very short answer type.
Mention the most significant function/role of tropic hormones

The main function of tropic hormones is to stimulate other endocrine glands to regulate the secretion of their hormones.


Short / Long answer type questions.
Mention the hormone(s) produced by the following and state the functions of each of the hormones.
(a) $$\beta$$-cells (pancreas),  (b) Cells of Leydig (testes),  (c) Parathyroid,  (d) Adrenal medulla

  Produced from Hormone Function
 (a)β -cells (pancreas)
 Insulin Acts to lower blood glucose levels
 (b) Cells of the Leydig (testes) Testosterone Promotes the development of male sexual characteristics including sperm development
 (c) Parathyroid Parathyroid hormone (PTH) Increases blood calcium levels in the blood when they are low
 (d) Adrenal medulla Adrenaline and noradrenaline (the catecholamines) 


Very short answer type.
Mention the site of secretion and function of the following.
Parathormone

Parathormone is secreted by parathyroid gland. Its function is to regulate calcium and phosphorus metabolism.


Very short answer type.
Mention the site of secretion and function of the following. Prolactin

Prolactin is secreted by anterior pituitary.

Function: maintenance of corpus luteum and continued production of progesterone in female mammals.


Very short answer type.
What is the basic difference between an endocrine gland and an exocrine gland?

 Endocrine gland Exocrine gland
 These glands do not discharge their secretions through glands. Their secretions directly reach the bloodstream. They are also known as ductless glands. Their secretions are hormones. Example: thyroid gland, pituitary gland, adrenal gland, pineal gland, etc. Exocrine glands discharge their secretions through ducts. Their secretions reach body surface and are mostly composed of enzymes and salts. Examples are sebaceous glands, lacrimal gland, salivary gland, etc.


Very short answer type.
Name the best known contribution of Aschner.

 Aschner carried hypophysectomy (removal of pituitary).


Match the following

(A) Pituitary gland - (5) Growth hormone - Growth hormone is secreted by the anterior lobe of the pituitary gland. Over-secretion of GH stimulates abnormal growth of the body leading to gigantism and low secretion of GH results in stunted growth resulting in pituitary dwarfism
(B) Pancreas - (1) Insulin and Glucagon -Pancreatic islets of Langerhans are of two major types. The α-cells secrete a hormone called glucagon, while the β-cells secrete insulin.
(C) Cranial nerves = (4) 12 - Cranial nerves are the 12 pairs of nerves that emerge directly from the brain
(D) Bicuspid valve - (2) Left atrioventricular valve -The opening between the left atrium and the left ventricle is guarded by a valve formed of two muscular flaps or cusps, the bicuspid valve or left atrioventricular valve.
(E) Tricuspid valve - (3) Right atrioventricular valve - The opening between the right atrium and the right ventricle is guarded by a valve formed of three muscular flaps or cusps, the tricuspid valve or right atrioventricular valve.


Find out the correct match of the organ, its enzymes and its function.
OrganEnzymesFunctions
LiverLipasesHelp in emulsification of fats, along with bile salts
Acini of pancreasAmylopsin (pancreatic juice)Digestion of animal starch into maltose
StomachRenin (in gastric juice)Converts caesin into paracraesin i.e curdling of milk
smallDipeptides (in succus entericus)Creates end products of protein digestion

The pancreas is involved in blood sugar control and metabolism within the body, and also in the secretion of substances pancreatic juice which helps digestion. Classically, these are divided into an "endocrine" role, relating to the secretion of insulin and other substances within pancreatic islets. The secretion of enzymes involved in digesting substances from outside of the body. In animals during digestion starch is converted into maltose. 
So the correct match is 'Acini of the pancreas'.


Name the following.
Hormone for regulating sugar level.

Insulin and glucagon


Name the following.
Flight - or - fight hormones.

Adrenaline and nor adrenaline are fight or flight hormones


Explain in brief the diseases caused by irregular secretions of Adrenal gland.

Diseases caused by the irregular secretion of adrenal glands are 
1. Addison's disease: It is caused due to deficiency of mineralocorticoids.
Symptoms: Reduced hunger, vomiting, reduced BMR & body temperature. dehydration & bronzing of the skin. 
2. Conn's disease: It is caused due to excess secretion of mineralocorticoids. 
Symptoms: Muscle weakness, high BR malfunctioning of kidneys etc. 
3. Cushing's disease: It is caused due to hypersecretion of corticosteroids.
Symptoms: Virilism, oedema, hyperglycaemia etc. In virilism, opposite secondary sexual characters appear and it is more common in women. The virilism in a female is also called as hirsutism. 


Name the hormone which prepares our body for action to face emergency situations like danger, fear, anger or excitement.

  • There are several glands in our body that secrete hormones that are crucial for growth, development, reproduction, etc. 
  • Different hormones affect the body's shape differently. This paper deals with the list and functions of significant hormones.
  • Adrenaline hormone in the adrenal gland and some of the neurons of the central nervous system are secreted in the medulla. 
  • It is also known as emergency hormone because it initiates the rapid response that makes the person believe and react to the stress rapidly. 
  • It raises the rate of metabolism, dilating blood vessels to the core and brain. 
  • During stressful circumstances, adrenaline releases rapidly into the blood, sending impulses to the organs to generate a particular reaction.


Class 11 Medical Biology Extra Questions