22

Q1. A steroid hormone which regulates glucose metabolism is

• 1) ll-Deoxycorticosterone
• 2) Corticosterone
• 3) Cortisone
• 4) Cortisol

Solution

Steroids are lipid hormones which are derived from cholesterol. Cortisol is secreted by the middle layer (i.e. zona fasciculata) of the adrenal cortex. Cortisol promotes gluconeogenesis (i.e. the formation of glucose from non-carbohydrates such as proteins). It also stimulates proteolysis and lipolysis.

Q2. Diabetes is due to

• 1) Na⁺ deficiency
• 2) Hormonal deficiency
• 3) Enzyme deficiency
• 4) Iodine deficiency

Solution

Diabetes mellitus occurs because of a deficiency of the insulin hormone which is secreted by the islets of Langerhans of the pancreas.

Q3. Name the part which connects the two lobes of the thyroid gland.

Solution

Isthmus

Q4. Write the names of the two regions which together constitute the adenohypophysis.

Solution

Pars distalis and pars intermedia together constitute the adenohypophysis.

Q5. Which one of the following pairs correctly matches a hormone with a disease resulting from its deficiency?  

• 1) Thyroxine - Tetany  
• 2) Luteinising hormone - Failure of ovulation  
• 3) Parathyroid hormone - Diabetes mellitus  
• 4) Insulin - Diabetes insipidus  

Solution

Luteinising hormone (LH) is secreted by the pars distalis or anterior pituitary.     In males, LH stimulates the synthesis of androgens from the testes. In females, it is responsible for the ovulation and release of the mature Graafian follicle, formation of the corpus luteum etc.     Low LH levels result in the failure of ovulation.  

Q6. State the significance of cortisols in the human body.

Solution

Significance of glucocorticoids in the human body: Glucocorticoids stimulate gluconeogenesis, proteolysis and lipolysis. They also inhibit the cellular uptake and use of amino acids. Cortisol maintains cardiovascular and kidney functions. Cortisol also produces anti-inflammatory reactions and suppresses the immune response. It also stimulates the production of red blood cells.

Q7. Excess of which of the following hormones causes Cushing's syndrome?  

• 1) Thyroxine  
• 2) Adrenaline  
• 3) Noradrenaline  
• 4) Cortisol  

Solution

Cushing’s syndrome is caused by the high level of cortisol secreted by the adrenal cortex.     It results in high blood pressure, bone loss, diabetes, Na⁺-K⁺ imbalance of blood plasma etc.  

Q8. Which one of the following is not a second messenger in hormone action?

• 1) cAMP
• 2) Sodium
• 3) Calcium
• 4) cGMP

Solution

Certain hormones such as peptide hormones or catecholamines have a large molecular size, or due to extreme polarity, they are unable to cross the plasma membrane. These hormones bind to the protein receptors present on the plasma membrane of the target cell. Secondary messengers are present within the target cell and produce the effect of the hormone inside the cell. As soon as the hormone binds to the receptors on the membrane, the secondary messengers are activated and their concentration in the cell increases. cAMP acts as a secondary messenger when epinephrine binds to protein receptors on the plasma membrane. Ca²⁺ ions also act as secondary messengers and are usually secreted into the cytoplasm by the endoplasmic reticulum. The presence of calcium in the cytoplasm triggers the effect of the hormone in the cell. cGMP also acts as a secondary messenger and mediates many cell and tissue responses. Especially in the heart, it slows muscle contraction in response to acetylcholine.

Q9. Trophic hormones are formed by  

• 1) Thyroid  
• 2) Posterior pituitary  
• 3) Middle pituitary  
• 4) Anterior pituitary  

Solution

Trophic hormones are the ones which stimulate other endocrine glands to secrete their hormones.     All the trophic hormones are secreted by the anterior pituitary.  

Q10. Name the middle layer of the adrenal cortex.

Solution

Zona fasciculata

Q11. Chemically, hormones are

• 1) Proteins only
• 2) Steroids only
• 3) Biogenic amines only
• 4) Proteins, steroids and biogenic amines

Solution

Hormones are chemical messengers which are released into the blood stream and have a specific effect on body functions. Chemically, hormones are of different types such as protein hormones, steroids and biogenic amines.

Q12. What is the scientific term for the formation of RBCs.

Solution

Erythropoiesis

Q13. Which hormone causes dilation of blood vessels, increased oxygen consumption and glucogenesis?

• 1) Glucagon
• 2) Insulin
• 3) ACTH
• 4) Adrenaline

Solution

Adrenaline elevates the glucose level in the blood stream by glucogenesis which is accompanied by an increase in oxygen consumption, body temperature and heat production. It also causes an increase in the flow of blood by dilating the blood vessels.

Q14. Which of the following hormones stimulates the release of viscous mucus from Brunner’s glands?

• 1) Cholecystokinin
• 2) Duocrinin
• 3) Villikinin
• 4) Secretin

Solution

Duocrinin secreted by the duodenal mucosa stimulates the release of viscous mucus from Brunner’s glands into the intestinal juice.

Q15. Which of the following diseases is not related to the thyroid gland?

• 1) Acromegaly
• 2) Myxoedema
• 3) Cretinism
• 4) Goitre

Solution

The growth hormone is secreted by the anterior lobe of the pituitary gland. Acromegaly is a disorder caused in adults due to the over secretion of growth hormone. In acromegaly, the bones of the jaw protrude and the palms and feet become broad. Facial features thicken.

Q16. What are hormone receptors?

Solution

Hormone receptors are the proteins present on target tissues to which hormones bind to produce their effect on target tissues.

Q17. Select the answer which correctly matches the endocrine gland with the hormone it secretes and its deficiency symptom.  

• 1) Endocrine gland     Hormone     Function/deficiency symptoms     Thyroid gland     Thyroxine     Lack of iodine in the diet results in goitre        
• 2) Endocrine gland     Hormone     Function/deficiency symptoms     Anterior pituitary     Oxytocin     Stimulates uterus contraction during childbirth        
• 3) Endocrine gland     Hormone     Function/deficiency symptoms     Corpus luteum     Testosterone     Stimulates spermatogenesis        
• 4) Endocrine gland     Hormone     Function/deficiency symptoms     Posterior pituitary     Growth hormone (GH)     Oversecretion stimulates abnormal growth        

Solution

The thyroid gland secretes thyroxine. Synthesis of thyroxine requires iodine. Hence, lack of iodine results in hypothyroidism deficiency, i.e. simple goitre.  

Q18. Name the two components of the testis. State the effects of testosterone on the central nervous system and in carbohydrate metabolism.

Solution

The testis is composed of seminiferous tubules and interstitial tissue. Testosterone acts on the central nervous system to influence libido and male behaviour. It produces anabolic effect on carbohydrate metabolism.

Q19. Which of the following hormones is secreted by the placenta?

• 1) All of the above
• 2) Oestrogen
• 3) Progesterone
• 4) Human chorionic gonadotropin (hCG)

Solution

The placenta secretes into the mother’s blood hormones such as oestrogens, progesterone and human chorionic gonadotropin (hCG).

Q20. Name the disorder caused by the deficiency of growth hormone during the development of children.

Solution

Dwarfism

Q21. State the function of gastrin.  

Solution

Gastrin stimulates the gastric glands to secrete hydrochloric acid and pepsinogen.  

Q22. Which one of the following hormones is a modified amino acid?

• 1) Oestrogen
• 2) Progesterone
• 3) Epinephrine
• 4) Prostaglandin

Solution

Modified amino acids are derived from a single amino acid. Epinephrine and norepinephrine are catecholamines; both are modified amino acids derived from tyrosine.

Q23. Which of the following induces parturition?  

• 1) Vasopressin  
• 2) GH  
• 3) Oxytocin  
• 4) TSH  

Solution

Oxytocin is secreted by the posterior lobe of the pituitary gland. It increases the contraction of the uterine muscles during parturition.  

Q24. FSH is secreted by

• 1) Posterior lobe of pituitary
• 2) Gonads
• 3) Hypothalamus
• 4) Anterior lobe of pituitary

Solution

Follicle-stimulating hormone (FSH) is secreted by the par distalis or the anterior pituitary. In males, FSH regulates spermatogenesis. In females, it stimulates the growth and development of the ovarian follicles.

Q25. Name the hormones which are collectively known as gonadotropins.

Solution

Luteinising hormone (LH) and follicle-stimulating hormone (FSH)

Q26. Write the function of prolactin.

Solution

Prolactin regulates the mammary gland and the formation of milk in the mammary glands.

Q27. Which of the following hormones contain iodine?

• 1) Adrenaline
• 2) Thyroxine
• 3) Insulin
• 4) Testosterone

Solution

Iodine is a part of thyroxine hormone. There are four iodine molecules per one molecule of thyroxine.

Q28. Gastric secretion is stopped by the hormone

• 1) Pancreozymin
• 2) Gastrin
• 3) Cholecystokinin
• 4) Enterogastrone

Solution

Enterogastrone is secreted by the mucosa of the duodenum; it inhibits the secretion of gastric juices and decreases gastric movements.

Q29. Match the hormone with its source of secretion. Somatostatin Pineal gland Melatonin Corpus luteum Aldosterone Placenta Progesterone Islet of Langerhans HCG Adenohypophysis   Adrenal gland  

• 1) A-1, B-3, C-4, D-2, E-5
• 2) A-2, B-1, C-4, D-6, E-3
• 3) A-1, B-6, C-4, D-3, E-5
• 4) A-5, B-1, C-4, D-3, E-6
• 5) A-4, B-1, C-6, D-2, E-3

Solution

Somatostatin 4. Islets of Langerhans Melatonin 1. Pineal gland Aldosterone 6. Adrenal gland Progesterone 2. Corpus luteum HCG 3. Placenta  

Q30. Find the odd one out with respect to the symptoms of Cushing syndrome.

• 1) None of the above
• 2) Obesity
• 3) Hypoglycemia
• 4) Osteoporosis

Solution

Hypoglycemia is a symptom found in Addison disease.

Q31. The adrenal gland in mammals is located

• 1) Near the pituitary
• 2) Above the kidney
• 3) Near the heart
• 4) Near the liver

Solution

A pair of adrenal glands is present one above each kidney on either side of the vertebral column.

Q32. Which one of the following pairs correctly matches a hormone with a disease resulting from its deficiency?

• 1) Thyroxine - Tetany
• 2) Insulin - Diabetes insipidus
• 3) Parathyroid hormone - Diabetes mellitus
• 4) Luteinising hormone - Failure of ovulation

Solution

Ovulation occurs under the influence of LH and FSH of the anterior pituitary gland.     Disease Deficiency Diabetes mellitus Insulin Tetany Parathormone Diabetes insipidus ADH    

Q33. Occurrence of Leydig cells and their secretion is

• 1) Testis and testosterone
• 2) Liver and cholesterol
• 3) Ovary and oestrogen
• 4) Pancreas and glucagon

Solution

Leydig cells are stimulated to produce male sex hormones, androgens by ICSH of the anterior pituitary. Testosterone is the main androgen and is a steroid hormone.

Q34. A common scent-producing gland among mammals is

• 1) Prostate gland
• 2) Adrenal gland
• 3) Bartholin gland
• 4) Anal gland

Solution

Scent or musk glands are located around the face, feet or anus of many mammals. These secrete pheromones which are involved in defence, recognition and territorial behaviour.

Q35. State the functions of oestrogen.

Solution

Functions of oestrogen: It stimulates the growth and activities of secondary sex organs in females. It stimulates the development of the ovarian follicle. It is responsible for the development of secondary sexual characters such as high pitch voice and the development of breasts in females. It regulates female sexual behaviour. It also promotes the development of mammary glands. (Write any three) 

Q36. Explain the role of hormones of the adrenal cortex.

Solution

Hormones secreted by the adrenal cortex are as follows: Corticoids Androgenic steroids Corticoids: Glucocorticoids stimulate proteolysis, gluconeogenesis and lipolysis. They inhibit the cellular uptake of amino acids. Cortisol, a glucocorticoid, maintains the cardiovascular system and kidney function. It produces anti-inflammatory reactions and suppresses the immune response. Cortisol also stimulates the production of red blood cells. The mineralocorticoid aldosterone acts on renal tubules and stimulates the reabsorption of sodium and water and the excretion of potassium and phosphate ions. Androgenic steroids: Promote the growth of pubic hair, axial hair and facial hair during puberty. 

Q37. Name the hormones involved in the metabolism of carbohydrates.

Solution

Glucocorticoids

Q38. During emergency, which of the following hormones is secreted?  

• 1) Aldosterone  
• 2) Adrenaline  
• 3) Thyroxine  
• 4) Calcitonin  

Solution

Adrenaline is secreted by the adrenal medulla. It mainly acts on smooth muscles, cardiac muscles, blood vessels, skeletal muscles and fat cells.     Adrenaline initiates the stress responses in the body.     It increases heart rate, blood pressure, metabolic rate, dilates blood vessels and increases the breathing rate and hence oxygen consumption and glucogenesis (i.e. the formation of glucose by the breakdown of liver glycogen), elevating the blood glucose levels.  

Q39. Progesterone is secreted by

• 1) Corpus luteum
• 2) Corpus albicans
• 3) Corpus callosum
• 4) Corpora radiata

Solution

The corpus luteum is a yellowish mass left behind after ovulation. It secretes progesterone which supports pregnancy and also prepares the mammary glands for lactation.

Q40. Describe the effects of hypothyroidism on pregnant women.

Solution

Effects of hypothyroidism on pregnant women: Hypothyroidism causes defective development and maturation of a growing baby resulting in cretinism. It also results in mental retardation, low intelligence, abnormal skin and deaf-mutism.

Q41. Name the two hormones synthesised by the follicular cells of the thyroid gland.

Solution

Two hormones synthesised by the follicular cells of the thyroid gland are Triiodothyronine (T₃) Tetraiodothyronine (T₄)

Q42. Accessory glands associated with the genital organs in female rats are I. Vestibular Bartholin’s II. Cowper's glands III. Ampullary glands IV. Vesicular glands

• 1) I and II
• 2) I only
• 3) III only
• 4) III and II
• 5) IV only

Solution

Vestibular Bartholin’s are exocrine glands. These glands lie under the labia majora. The secretion of these glands provides lubrication during sexual intercourse.

Q43. Which hormone is responsible for the rise in blood sugar?

• 1) Glucagon
• 2) Insulin
• 3) Somatostatin
• 4) All of the above

Solution

Glucagon is responsible for the rise in blood sugar levels.

Q44. What is the other name for vasopressin?

Solution

Anti-diuretic hormone (ADH)

Q45. Name the cells which secrete erythropoietin.  

Solution

The juxtaglomerular cells of the kidneys secrete erythropoietin.  

Q46. Secretion of progesterone by the corpus luteum is initiated by

• 1) Thyroxine
• 2) MSH
• 3) Testosterone
• 4) LH

Solution

LH secreted by the anterior pituitary stimulates the corpus luteum to secrete progesterone.

Q47. Which of the following is correctly matched?

• 1) Parathyroid - Tetany
• 2) Insulin - Diabetes insipidus
• 3) Adrenaline - Hepatitis
• 4) Thyroxine - Tetanus

Solution

Parathormone is secreted by the parathyroid gland. This hormone increases the blood calcium level. In case of its deficiency, the blood plasma levels of calcium fall significantly. The nerve cells reaching the muscles cause frequent stimulation in muscles which leads to the sustained contraction of muscles of feet, hands, larynx etc. which is called muscular tetany.

Q48. Damage to the thymus in a child may lead to  

• 1) Loss of antibody-mediated immunity  
• 2) A reduction in haemoglobin content of blood  
• 3) Loss of cell-mediated immunity  
• 4) A reduction in stem cell production  

Solution

The thymus secretes the hormone thymosin which stimulates the differentiation of T-lymphocytes. T-lymphocytes provide cell-mediated immunity. In old age, the thymus gland degenerates; hence, immune responses in old people are weak.     Hence, damage to the thymus gland in a child will hamper the differentiation of T-lymphocytes which provide immunity.  

Q49. In human adult females, oxytocin

• 1) Is secreted by the anterior pituitary
• 2) Stimulates pituitary to secrete vasopressin
• 3) Causes strong uterine contractions during parturition
• 4) Stimulates the growth of mammary glands

Solution

Oxytocin is secreted by the posterior pituitary. It is a peptide hormone which stimulates the contraction of uterine muscles during birth. It also stimulates the ejection of milk from the mammary glands after the delivery of a child.

Q50. State the functions of thyroid hormones.

Solution

Functions of thyroid hormones: They support the process of red blood cell formation. They regulate the basal metabolic rate. They control the metabolism of carbohydrates, proteins and fats. They influence the maintenance of water and electrolyte balance in the body. They secrete thyrocalcitonin which regulates the blood calcium level.

Q51. Sertoli cells are regulated by the pituitary hormone known as

• 1) GH
• 2) Prolactin
• 3) LH
• 4) FSH

Solution

Sertoli cells protect the spermatids and provide nutrients to both developing and mature spermatozoa. They are regulated by follicle-stimulating hormone (FSH) as FSH receptors are confined to Sertoli cells.

Q52. Which of the following hormones stimulates the secretion of milk in females?

• 1) Progesterone
• 2) LH
• 3) Prolactin
• 4) Oxytocin

Solution

Oxytocin is secreted by the posterior pituitary. It is a peptide hormone which stimulates the contraction of uterine muscles during birth. It also stimulates the ejection of milk from the mammary glands after the delivery of a child.

Q53. The 'islets of Langerhans' are found in

• 1) Alimentary canal
• 2) Liver
• 3) Pancreas
• 4) Stomach

Solution

The islets of Langerhans were first found by a German medical student Paul Langerhans. There are three kinds of islets of Langerhans found in the pancreas - α-cells, β-cells and δ-cells. α-cells secrete glucagon, β-cells secrete insulin and δ-cells secrete somatostatin.

Q54. Match the source gland with its respective hormone and function and select the correct option. Gland Secretion Effect on body A Oestrogen Maintenance of secondary sexual characters Alpha cells of islets of Langerhans B Raises blood sugar level Anterior pituitary C Oversecretion leads to gigantism  

• 1) A B C placenta glucagon calcitonin
• 2) A B C ovary insulin calcitonin
• 3) A B C placenta insulin vasopressin
• 4) A B C ovary glucagon Growth hormone

Solution

Gland Secretion Effect on body A (Ovary) Oestrogen Maintenance of secondary sexual characters Alpha cells of Islets of Langerhans B (Glucagon) Raises blood sugar level Anterior pituitary C (Growth hormone) Oversecretion leads to gigantism  

Q55. Which hormone is called hyperglycemic hormone? Why?

Solution

Glucagon is called hyperglycemic hormone. Glucagon causes glycogenolysis (i.e. break down of glycogen into glucose) and gluconeogenesis (i.e. synthesis of glucose from non-carbohydrates). It also reduces the cellular glucose uptake and utilisation. This results in an increase in the blood glucose level. Hence, glucagon is called a hyperglycemic hormone.

Q56. Immune responses in old people are weak. Give reasons.

Solution

The thymus gland secretes thymosin which is responsible for the differentiation of T-lymphocytes and the production of antibodies. T-lymphocytes provide cell-mediated immune response, while antibodies provide humoral immunity. In old age, the thymus gland degenerates which results in the reduced production of thymosin. Hence, the immune responses are weak in old people.

Q57. Steroid hormones easily pass through the plasma membrane by simple diffusion because they

• 1) Are water-soluble
• 2) Contain carbon and hydrogen
• 3) Enter through pores
• 4) Are lipid-soluble

Solution

Steroid hormones are lipophilic in nature. The lipids present in the cell membranes do not prohibit the entry of lipophilic molecules in the cell. Hence, steroid hormones are easily diffused through the cell membrane.

Q58. Explain the role of androgens in the human body.

Solution

Androgens regulate the development of male accessory organs such as vas deferens, epididymis, seminal vesicles, prostate glands and urethra. They stimulate the development of secondary sexual characters such as aggressiveness, low pitch voice, growth of axial and facial hair and muscular growth. They stimulate spermatogenesis. They act on the central nervous system to influence male behaviour. They also play an anabolic role in protein and carbohydrate metabolism.

Q59. A steroid hormone which regulates glucose metabolism is?

• 1) Corticosterone
• 2) Cortisone
• 3) Cortisol
• 4) 11-deoxycorticosterone

Solution

Cortisol is a steroid hormone secreted by the adrenal cortex. The hormone stimulates gluconeogenesis which helps to maintain the blood glucose levels.

Q60. Expand the term ANF. How does ANF help to reduce blood pressure?  

Solution

ANF: Atrial natriuretic factor     At high blood pressure, ANF which is secreted causes the dilation of blood vessels. This helps in reducing the blood pressure.  

Q61. According to the accepted concept of hormone action if receptor molecules are removed from target organs, then the target organ will

• 1) continue to respond to the hormone without any difference
• 2) continue to respond to the hormone but will require higher concentration
• 3) not respond to the hormone
• 4) continue to respond to the hormone but in the opposite way

Solution

Hormones are released in the blood, but each hormone stimulates only a specific target organ to initiate a specific response. It is due to the presence of a specific receptor protein in a specific target cell. If these receptor molecules are removed from the target organs, then the organ will not respond to the hormone.

Q62. Chemically hormones are categorised as peptide hormones, steroids, non-peptide hormones, amines etc. According to you, in which categories glucagon and insulin hormones can be placed? Name the cells on which glucagon and insulin show their influence.

Solution

Glucagon and insulin are peptide hormones. Glucagon acts on hepatocytes, while insulin acts on hepatocytes and adipocytes.

Q63. Name the hormones which stimulate the formation of sac-like structures to store milk in females.

Solution

Progesterone

Q64. Gonadotropic hormones are produced in the

• 1) Posterior part of the thyroid
• 2) Adenohypophysis of the pituitary
• 3) Adrenal cortex
• 4) Interstitial cells of the testes

Solution

The gonadotropic hormones such as FSH and ICSH are secreted by the anterior lobe of the pituitary—the adenohypophysis.

Q65. Name the hormone which stimulates glycogenesis.

Solution

Insulin

Q66. The fight and flight hormone is

• 1) Adrenaline
• 2) Thyroxine
• 3) Oxytocin
• 4) ADH

Solution

Adrenaline and noradrenaline are secreted by the adrenal gland. Both hormones show antagonistic effects and are responsible for the fight and flight response of the body. Adrenaline initiates the stress responses in the body. It mainly acts on smooth muscles, cardiac muscles, blood vessels, skeletal muscles and fat cells. It increases heart rate, blood pressure, metabolic rate, dilates blood vessels and increases the breathing rate and hence oxygen consumption and glucogenesis (i.e. the formation of glucose by the breakdown of liver glycogen), elevating the blood glucose levels.

Q67. State the function of somatostatin.

Solution

Somatostatin inhibits the release of the growth hormone from the pituitary gland.

Q68. Which out of the following pairs is incorrectly matched?

• 1) Corpus luteum - Relaxin (secretion)
• 2) Somatostatin - Delta cells (source)
• 3) Insulin - Diabetes mellitus (disease)
• 4) Glucagon - Beta cells (source)

Solution

Glucagon is a polypeptide hormone which is secreted by the α-cells of pancreas. This hormone is responsible for raising the blood glucose level by breaking down glycogen into glucose and promoting the conversion of non-carbohydrate substances into glucose. β-cells secrete insulin which lowers the blood glucose level.

Q69. How does the body acquire the hypoglycemic state?

Solution

Insulin secreted by β-cells of islets of Langerhans acts on hepatocytes and adipocytes. This stimulates the cellular uptake and utilisation of glucose. Insulin also stimulates glycogenolysis (i.e. the process of conversion of glucose to glycogen). This results in rapid movement of glucose from the blood to hepatocytes and target cells, resulting in a decreased level of blood sugar. Thus, hypoglycemia is achieved by the body.

Q70. Represent diagrammatically the action of the hormone oestrogen.

Solution

 

Q71. When both ovaries are removed from rat, which hormone is decreased in blood?

• 1) Oestrogen
• 2) Prolactin
• 3) Oxytocin
• 4) Gonadotropin-releasing factor

Solution

If both ovaries are removed from rat, then the blood plasma level of oestrogen will be affected as it is produced by the theca interna cells of the Graafian follicles.

Q72. Select the correct matching pair of a hormone along with its source and function.  

• 1) Hormone     Source     Function     Norepinephrine     Adrenal medulla     Normalises heart beat, rate of respiration and creates alertness        
• 2) Hormone     Source     Function     Prolactin     Posterior pituitary     Regulates growth of mammary glands and milk formation in females        
• 3) Hormone     Source     Function     Glucagon     -cells of islets of Langerhans     Stimulates glycogenolysis        
• 4) Hormone     Source     Function     Vasopressin     Posterior pituitary     Increases loss of water through urine        

Solution

Norepinephrine is secreted by the adrenal medulla. Norepinephrine and epinephrine have antagonistic effects on the body. They are secreted during the fight and flight mechanism.  

Q73. Write the other two names used for the posterior pituitary.

Solution

Neurohypophysis and pars nervosa

Q74. Insulin is

• 1) Enzyme
• 2) Vitamin
• 3) Lipid
• 4) Hormone

Solution

Insulin is the earliest known hormone which is also called the hypoglycaemic factor as it decreases the glucose level in the blood and prevents the occurrence of diabetes. It is secreted by β-cells of the islets of Langerhans.

Q75. Progesterone, which is the most important component of oral contraceptive pills, prevents pregnancy by

• 1) Creating an unfavourable chemical environment for the sperms to survive in the female reproductive tract
• 2) Preventing the cleavage of the fertilised egg
• 3) Preventing the formation of the egg
• 4) Blocking ovulation

Solution

Contraceptive pills contain oestrogen and progesterone which disturb the normal menstrual cycle to prevent ovulation. They inhibit the pituitary from secreting FSH and LH and block ovulation.

Q76. Name the elements necessary for the synthesis of thyroid hormones.

Solution

Iodine

Q77. Muscular tetany can be caused by the deficiency of

• 1) Parathyroid hormone
• 2) Oxytocin
• 3) Thyroxine
• 4) STH
• 5) ADH

Solution

Parathormone is secreted by the parathyroid gland. This hormone increases the blood calcium level. In case of its deficiency, the blood plasma levels of calcium fall significantly. The nerve cells reaching muscles cause frequent stimulation in muscles which leads to the sustained contraction of muscles of feet, hands, larynx etc. which is called muscular tetany.

Q78. Describe the journey of hypothalamus hormones to their target organs.

Solution

Hormones of the hypothalamus are secreted by their neurosecretory cells. These hormones then pass through axons and are released from their nerve endings. The hormones reach the anterior pituitary through the portal circulatory system and regulate the functions of the anterior pituitary or adenohypophysis. Neurohypophysis is under the direct neural regulation of the hypothalamus.

Q79. Name the main mineralocorticoid of the human body.

Solution

Aldosterone

Q80. Name the part of the brain which has neural as well as hormonal function.

Solution

Hypothalamus

Q81. LH and FSH are collectively called

• 1) Oxytocin
• 2) Luteotropins
• 3) Gonadotropins
• 4) Somatotropins

Solution

FSH stimulates spermatogenesis in males and promotes the growth of ovarian follicles in females. LH stimulates the testes to secrete testosterone in males, and it is responsible for ovulation and the formation of the corpus luteum in females. Both hormones are secreted by the anterior lobe of the pituitary gland. Because both hormones show their effects on the gonads, they are collectively called gonadotropins.

Q82. Name the hormone which decreases blood pressure.  

Solution

Atrial natriuretic factor (ANF)  

Q83. 'Mammalian thymus' is mainly concerned with  

• 1) Regulation of body temperature  
• 2) Regulation of body growth  
• 3) Immunological functions  
• 4) Secretion of thyrotropin  

Solution

The thymus gland secretes the hormone called thymosin.     Thymosine stimulates the differentiation of T-lymphocytes which are responsible for cell-mediated immunity.     Thymosine also promotes the production of antibodies which are part of the humoral immunity of the body.  

Q84. Which of the following hormones helps in the contraction of the uterus during childbirth?

• 1) Oxytocin
• 2) ADH
• 3) Glucocorticoid
• 4) Androgen

Solution

Oxytocin is secreted by the posterior pituitary. It is a peptide hormone which stimulates the contraction of uterine muscles during birth.

Q85. Which of the following hormones has been found identical with cholecystokinin?

• 1) Gastrin
• 2) Secretin
• 3) Pancreozymin
• 4) Duocrinin

Solution

Pancreozymin is a hormone secreted by duodenal mucosa which is identical with cholecystokinin.

Q86. Feeling the tremors of an earthquake, a scared resident of the seventh floor of a multi-storeyed building starts climbing down the stairs rapidly. Which hormone initiated this action?

• 1) Thyroxine
• 2) Glucagon
• 3) Adrenaline
• 4) Gastrin

Solution

Adrenaline is responsible for this action as the hormone is known as 3F hormone—fright, fight and flight.

Q87. Which of the following is an accumulation and release centre of neurohormones?

• 1) Hypothalamus
• 2) Intermediate lobe of the pituitary
• 3) Posterior pituitary lobe
• 4) Anterior pituitary lobe

Solution

All secretion by the pituitary gland is controlled by a hormonal signal from the hypothalamus. The neurohormones are secreted and accumulated by the hypothalamus.

Q88. Which one of the following part is an endocrine gland?

• 1) Brunner's glands
• 2) Juxtaglomerulus
• 3) Pars radiata
• 4) Crypts of Lieberkühn

Solution

Cells of the juxtaglomerulus secrete erythropoietin which stimulates the process of formation of red blood cells, i.e. erythropoiesis.

Q89. Delta cells secrete

• 1) Insulin
• 2) Somatostatin
• 3) Glucagon
• 4) Cortisol

Solution

Delta cells in the islets of Langerhans secrete somatostatin.

Q90. Which of the following is a hormone of the kidney?

• 1) Estradiol
• 2) Epinephrine
• 3) Renin
• 4) Aldosterone

Solution

Cells close to the glomeruli in the cortex of the kidneys are endocrine. They secrete a hormone called renin.

Q91. Describe the significance of the adrenal medulla in regulating physiological functions of the body.

Solution

The adrenal medulla secretes two catecholamines - adrenaline and noradrenaline. These hormones are secreted in response to stress experienced by the body or during an emergency. These hormones bring the following changes: Alertness Pupillary dilation Piloerection Sweating Increase in heart beat and breathing rate Increase in strength of heart contraction Catecholamines are also responsible for the increase in blood glucose level, because they are responsible for the breakdown of glycogen in the liver.

Q92. The pineal gland of the human brain secretes melatonin concerned with  

• 1) Anger  
• 2) Colouration of skin  
• 3) Lactation  
• 4) Parturition  

Solution

Melatonin is an amine hormone derived from tryptophan.     The gland is light sensitive, and the secretion of melatonin is influenced by light.     Melatonin stimulates the melanocytes of the skin to produce more melanin, a skin pigment.  

Q93. Which of the following is not a hereditary disease?

• 1) Cystic fibrosis
• 2) Haemophilia
• 3) Thalassaemia
• 4) Cretinism

Solution

Cretinism is caused by the deficiency of thyroxine-releasing hormone, thyroid-stimulating hormone or insufficient intake of iodine. It slows down the mental and physical development of the child and reduces the metabolic rate. The skin is abnormal. The body temperature and blood pressure are lower than normal.

Q94. Withdrawal of which of the following hormones is the immediate cause of menstruation?

• 1) FSH and LH
• 2) FSH
• 3) Progesterone
• 4) Oestrogens

Solution

Progesterone is secreted by the corpus luteum. It prevents ovulation and hence supports pregnancy. Thus, its withdrawal will be the immediate cause of menstruation.

Q95. Adrenaline directly affects

• 1) Epithelial cells of the stomach
• 2) β-cells of Langerhans
• 3) Dorsal root of the spinal cord
• 4) SA node

Solution

Adrenaline or epinephrine is secreted by the adrenal medulla. This hormone is responsible for the increase in heart rate, breathing and blood glucose level.

Q96. Name the cell which secretes glucagon.

Solution

α-cells  

Q97. How is the secretion of the parathyroid hormone regulated?

Solution

The circulating calcium ions in blood regulate the secretion of the parathyroid hormone.

Q98. Name the processes which are initiated by the secretion of glucagon.

Solution

Gluconeogenesis and glycogenolysis

Q99. Oestrogen and testosterone are steroid hormones, and they most likely bind to

• 1) Cytoplasmic receptors
• 2) Membrane ion channels
• 3) Enzyme-linked membrane receptors
• 4) G-protein coupled membrane receptors

Solution

Steroid hormones are lipophilic in nature. The lipids present in the cell membranes do not prohibit the entry of lipophilic molecules in the cell. Hence, steroid hormones easily diffuse through the cell membrane. When they enter the cell, they either bind to the cytoplasmic receptors or nucleic receptors to produce their effects.

Q100. Name the cells of the endocrine pancreas.

Solution

Islets of Langerhans

Q101. Read the following functions and identify the hormones. Maintains osmotic and blood pressure in the body Inhibits the cellular uptake of amino acids Growth of axial hair during puberty Dilation of pupils

Solution

Maintains osmotic and blood pressure in the body - Aldosterone Inhibits the cellular uptake of amino acids - Glucocorticoids Growth of axial hair during puberty - Androgenic steroids Dilation of pupils - Adrenaline and noradrenaline

Q102. Name the gland present on the dorsal side of the forebrain.

Solution

The pineal gland

Q103. Ovulation is stimulated by

• 1) FSH
• 2) LH
• 3) Progesterone
• 4) Oestrogen

Solution

Ovulation occurs on the 14th day of the menstrual cycle which is stimulated by luteinising hormone secreted by the anterior pituitary gland.

Q104. Name the disorder caused by hyposecretion of insulin.

Solution

Diabetes mellitus

Q105. Tablets to prevent contraception contain

• 1) FSH
• 2) LH
• 3) Both FSH and LH
• 4) Progesterone

Solution

Contraceptive pills for women contain the female sex hormones oestrogen and progesterone. These prevent the development of eggs and ovulation by inhibiting the secretion of FSH.

Q106. An adenohypophysis hormone which is regulated by the feedback mechanism is

• 1) Vasopressin
• 2) Oxytocin
• 3) Calcitonin
• 4) Cortisone
• 5) TSH

Solution

Thyroid-stimulating hormone (TSH) is secreted by the adenohypophysis. It controls the secretion of thyroid hormones by the thyroid gland. To maintain the levels of thyroxine in blood under normal, the secreted thyroxine shows a negative effect of the adenohypophysis which inhibits the secretion of TSH.

Q107. Name the sac in which the testes are located.

Solution

Scrotal sac or scrotum

Q108. Name the hormone secreted by the atrial walls of the human heart.

Solution

Atrial natriuretic factor (ANF)

Q109. Which is the main glucocorticoid found in the human body?

Solution

Cortisol

Q110. Name the types of hormones based on their chemical nature.

Solution

The types of hormones based on their chemical nature are Peptide hormones Steroids Iodothyronines Amino acid derivatives

Q111. State the two symptoms of diabetes mellitus.

Solution

The symptoms of diabetes mellitus are Loss of glucose through urine Formation of harmful ketone bodies

Q112. What are the categories of hormones based on their chemical nature? Give one example of each category.

Solution

The types of hormones based on their chemical nature are Peptide hormones: Insulin and glucagon Steroids: Testosterone and progesterone Iodothyronines: Thyroid hormones Amino acid derivatives: Epinephrine

Q113. Name the structures which secrete oestrogen and progesterone. Which hormone is responsible for the high pitch of voice in females and for pregnancy?

Solution

The growing ovarian follicle secretes oestrogen, and the corpus luteum secretes progesterone. Oestrogen is responsible for the high pitch voice in females, while progesterone supports pregnancy.

Q114. Name the hormone of the hypothalamus which controls the secretions of gonadotropins from the pituitary glands.

Solution

Gonadotropin-releasing hormone (GnRH).

Q115. Name the basal part of the diencephalon.

Solution

Hypothalamus

Q116. Ajay had participated in a running race. He was excited and stood first in the race. When he finished the race, his heart was beating fast, and he was breathing heavily with a lot of sweat. What could be the reason for these changes in him after the race?

Solution

When Ajay started running, his body experienced a lot of stress. In response to the stress, the adrenal medulla secreted two hormones epinephrine and norepinephrine. Secretion of these hormones resulted in sweating, increased heart beat, increased respiration, piloerection etc.

Q117. Represent diagrammatically the adrenal gland and its sections showing the layers of tissues.

Solution

       

Q118. In the human body, some hormones work antagonistically to control certain metabolic processes. Give one such example where two hormones work antagonistically in a pair. Name the metabolism controlled by their action. Name the glands which secrete these antagonistic hormones. Name the target organs on which these hormones show their action. What value do you learn from the working of antagonistic hormones?

Solution

Glucagon and insulin. They both work to maintain the normal blood sugar level. Glucagon is secreted by the α-cells and insulin is secreted by the β-cells of the pancreas. Glucagon acts on hepatocytes and insulin acts on hepatocytes and adipocytes. Working in a team makes the task easy and achievable.

Q119. Name the cells which produce testosterone.

Solution

Interstitial cells or Leydig cells

Q120. State the functions of oxytocin.

Solution

Functions of oxytocin: Stimulates the contraction of smooth muscles. It causes the contraction of uterine muscles at the time of parturition (childbirth). It is also responsible for milk ejection from the mammary glands.

Q121. Name the hormone secreted by the corpus luteum.

Solution

Progesterone is secreted by the corpus luteum.

Q122. Name the hormone which regulates the blood calcium level.

Solution

Thyrocalcitonin

Q123. State the functions of thymosin.

Solution

Functions of thymosin: It promotes the differentiation of T-lymphocytes which are responsible for cell-mediated immunity. It promotes antibody production which is responsible for humoral immunity.

Q124. Name any two peptide hormones secreted by the walls of the GI tract.

Solution

Secretin and cholecystokinin (CCK)

Q125. Name the cavity in which the pituitary gland is located.

Solution

Sella turcica

Q126. State the term used for the formation of spermatozoa.

Solution

Spermatogenesis

Q127. Calcium balance in the body is difficult without parathyroid hormone. Justify.

Solution

The parathyroid hormone increases the calcium levels in the body. It acts on bones and promotes demineralisation or bone resorption of calcium. It also stimulates the resorption of calcium by the renal tubules. It increases the absorption of calcium from the digested food by the microvilli of the small intestine. When there is low calcium in blood, it helps to increase the calcium level of the blood. Hence, the calcium balance in the body is difficult without the parathyroid hormone.

Q128. State the two kinds of islets of Langerhans present in the pancreas.

Solution

Two kinds of islets of Langerhans present in the pancreas are α-cells and β-cells.

Q129. State the functions of progesterone in females.

Solution

Functions of progesterone in females: Progesterone supports pregnancy. It acts on mammary glands and stimulates milk secretion. It also promotes the development of sac-like structures in mammary glands to store milk.

Q130. Name the two hormones which are synthesised by the hypothalamus but are known as the secretions of the pituitary gland.

Solution

Oxytocin and vasopressin

Q131. Give examples where melatonin regulates the 24-hour rhythm of an organism’s body.

Solution

It maintains the normal sleep-wake cycle. It adjusts and maintains the body temperature according to the temperature of the external environment.

Q132. Show the mechanism of action of FSH.

Solution

 

Q133. What is the source of melatonin? What is the function of melatonin?

Solution

Melatonin is secreted by the pineal gland. It plays a role in the regulation of the diurnal rhythm of our body.

Q134. Write functions of the following hormones: Thyroid-stimulating hormone LH in males

Solution

Thyroid-stimulating hormone - Stimulates the synthesis of thyroxine LH in males - Stimulates the synthesis of androgens in males

Q135. Name the gland which has exocrine as well as endocrine secretions.

Solution

Pancreas

Q136. Explain the two types of hormones produced by the hypothalamus.

Solution

The two types of hormones produced by the hypothalamus are Releasing hormones which stimulate the secretion of pituitary hormones. Inhibiting hormones which inhibit the secretion of pituitary hormones.

Q137. Describe the secretions of endocrine glands in one sentence.

Solution

Secretions of the endocrine glands are hormones which are non-nutrient chemicals which act as intercellular messengers and are produced in trace amounts.

Q138. Name the hormone secreted by the pars distalis.

Solution

Melanocyte-stimulating hormone (MSH)

Q139. Give any two examples of steroid hormones.

Solution

Oestradiol and cortisol

Q140. Name the hormone which stimulates the reabsorption of Na⁺ ions and water in the renal tubule and excretion of K⁺ ions.

Solution

Aldosterone

Q141. Which hormone do β-cells secrete?

Solution

Insulin

Q142. What are the hormone receptors present on the cell membrane called?

Solution

Membrane-bound receptors

Q143. Differentiate between gonadotropins in males and females.

Solution

Gonadotropins in Males Gonadotropins in Females LH stimulates the synthesis of androgens from the testes. LH induces ovulation and maintains the corpus luteum. FSH regulates spermatogenesis. FSH stimulates the growth and development of ovarian follicles.  

Q144. State the function of mineralocorticoids.

Solution

Mineralocorticoids help in maintaining the balance of water and electrolytes in the body.

Q145. How catecholamines are responsible for the increased level of blood glucose?

Solution

Catecholamines stimulate the breakdown of glycogen which results in an increase in the blood glucose level.