CBSE Class 11 Biology HOTs Chemical Co-Ordination And Integration

Question. Moon face, buffalo hump, centripetal deposition of fat in belly occurs due to the abnormal functioning of
(a) adrenal medulla
(b) adrenal cortex
(c) anterior pituitary
(d) thyroid gland.

Answer. B

Question. Study the following flow chart that shows calcium regulation by different hormones and identify X, Y and Z.
Anterior lobe of pituitary gland
↓ X
C-cells of thyroid gland
↓ Y
Blood calcium level decreases
↓
Stimulation of chief cells of parathyroid gland
↓ Z
Regulates calcium and phosphate levels in blood
(a) X-Calcitonin, Y-Thyrotropin, Z-Calcitriol
(b) X-Thyrotropin, Y-Calcitriol, Z-Parathormone
(c) X-Thyrotropin, Y-Calcitonin, Z-Parathormone
(d) X-Thyrotropin releasing hormone,
Y-Thyrotropin, Z-Parathormone

Answer. C

Question. Read the given statements and select the correct option.
Statement A : MSH and Melatonin are antagonistic hormones.
Statement B : MSH help in the wide distribution of melanin in melanocytes while melatonin collects the melanin at one place in melanocyte.
(a) Both statements A and B are true and B is the correct explanation of A.
(b) Both statements A and B are true but B is not the correct explanation of A.
(c) Statements A is true but B is false.
(d) Both statements A and B are false.

Answer. A

Question. Read the following statements and choosethe  incorrect one.
(a) Corpus luteum only secretes progesterone.
(b) GIP inhibits gastric secretions and contractions.
(c) Cortisol is also considered as stress hormone.
(d) Glucagon stimulates glycogenolysis in liver.

Answer. A

Question. Which of the following statement is incorrect with respect to action of FSH hormone?
(a) It interacts with membrane bound receptors and normally does not enter the target cell.
(b) It generates second messengers like cyclic AMP and Ca++.
(c) It regulates gene expression or chromosome function by the interaction of hormone receptor complex with genome.
(d) It binds with receptors on the ovarian cellme mbrane and regulates physiological responses like ovarian growth.

Answer. C

Question. Observe the given figures and select the option that correctly identifies the labels A, B, C and D. 

             A         B        C       D
(a) Parathyroid Isthmus Trachea Thyroid gland gland
(b) Thyroid gland Isthmus Trachea Parathyroid gland
(c) Thyroid gland Isthmus Larynx Parathyroid gland
(d) Thyroid gland Corpus Trachea Parathyroid luteum gland

Answer. B

Question. When the primary sexual organ does not develop, puberty may appear due to
(a) stimulation of adrenal cortex
(b) stimulation of adrenal medulla
(c) excessive secretion from gonads
(d) none of these.

Answer. A

Question. Which of the following functions are regulated by melatonin/pineal gland?
A. Defense capability B. Pigmentation
C. Menstrual cycle D. Metabolism
E. Growth and differentiation
F. Body temperature
G. Sleep-wake cycle
(a) A, D, C, F and G
(b) B, C, D, E, F and G
(c) A, C, D and E
(d) A, B, C, D, F and G

Answer. D

Question. FSH of anterior pituitary acts on
(a) interstitial cells of testis
(b) sertoli cells of testis
(c) parafollicular cells of thyroid
(d) sustentacular cells of testis.

Answer. B

Question. During stress, besides epinephrine and norepinephrine which other hormones are also released ?
(a) Thyroxine, cortisol, aldosterone and vasopressin
(b) Cortisol, aldosterone, vasopressin and glucagon
(c) Cortisol, vasopressin, insulin and parathormone
(d) Parathormone, vasopressin, glucagon and thyroxine

Answer. B

Question. Study the given diagram showing the anatomy of  pancreas and i d e n t i f y t h e hormones secreted from labelled parts A, B and C.

(a) A-Insulin, B-Somatostatin, C-Glucagon
(b) A-Pancreatic polypeptide, B-Glucagon, C-Insulin 
(c) A-Somatostatin, B-Pancreatic polypeptide, C-Glucagon
(d) A-Somatostatin, B-Insulin, C-Glucagon

Answer. D

Question. Recognise the given figure A B and find out the correct matching. 
(a) A-Adrenal gland, B-Kidney
(b) A-Kidney, B-Adrenal gland
(c) A-Adrenal medulla, B-Adrenal cortex
(d) A-Adrenal cortex, B-Adrenal medulla

Answer. D

Case Based MCQs

Read the following passage and answer the questions from 41 to 45 given below.
Certain hormones in body are secreted by glands X in response to stress during emergency situations. These hormones increase alertness, pupillary dilation, heart beat and rate of respiration. Hormone secreted by Y is the salt retaining hormone and is responsible for regulation of minerals metabolism.

Question. Catecholamines are derived from which amino acid?
(a) Tryptophan
(b) Phenylalanine
(c) Glutamine
(d) Tyrosine

Answer. D

Question. Name the disease caused by deficiency of hormone secreted by Y.
(a) Addison’s disease
(b) Cushing’s syndrome
(c) Adrenal viruism
(d) Conn’s syndrome

Answer. A

Question. Category of hormone secreted Y is
(a) glucocorticoid
(b) gonadocorticoid
(c) mineralocorticoid
(d) Catecholamine.

Answer. C

Question. Identify the endocrine glands X and Y.
          X          Y
(a) Adrenal gland Pituitary
(b) Hypothalamus Adrenal gland
(c) Adrenal medulla Adrenal cortex
(d) Adrenal cortex Pineal gland

 Answer. C

Question. Which of the following hormones are secreted during emergency situations?
(a) Calcitonin and thymosin
(b) Adrenaline and nor-adrenaline
(c) Aldosterone and adrenaline
(d) Epinephrine only

Answer. B

Very Short Answer Type Questions

Question. Which disease is caused due to hypo functioning of Sertoli cells?

Answer. Male hypogonadism occurs due to the deficiency of androgens-male sex hormones (hypofunction of leydig’s cells), deficiency of sperm formation (hypofunction of Sertoli cells) or both, before puberty. As a result male secondary sexual characters and musculature do not develop.

Question. Name the hormones secreted from the thyroid gland.

Answer. (c) The hormones secreted from the thyroid gland are: Thyroxine (T4), Tri-iodothyronine (T3) and Calcitonin.

Question. Which hormone is secreted in an inactive form?

Answer. Insulin

Question. What are neurohormones?

Answer.  Higher animals with well developed nervous system produce special type of hormones, called neurohormones, secreted by some modified nerve cells, and possessing functional characteristics of both nerve and endocrine cells. e.g. oxytocin, ADH, etc.

Question. Name any two heterocrine glands.

Answer.  (i) Testes (ii) Pancreas

Short Answer Type Questions

Question. Differentiate between cretinism and dwarfism. Short Answer Type Questions

Answer. Differences between cretinism and dwarfism are : 

Question. Explain the endocrine role of placenta.

Answer. Placenta is an intimate connection between the fetus and the uterine wall of the mother to exchange the materials. It is temporarily an endocrine gland. It secretes some hormones like estrogen, progesterone, human chorionic gonadotropin (hCG), human chorionic somatomammotropin – hCS (formerly known as human placental lactogen), chorionic thyrotropin, chorionic corticotropin and relaxin. Estrogen and progesterone have the same roles as in the nonpregnant state. However, the placental progesterone also checks contraction of uterine muscles and thus helps to maintain pregnancy. hCG stimulates progesterone release from the corpus luteum and maintains it. Presence of hCG in urine indicates pregnancy. Human choronic somatomammotropin stimulates the growth of mammary glands. Placental relaxin causes relaxation of the ligaments of pubic symphysis and towards the termination of pregnancy it softens and widens the opening of the cervix for easy child birth.

Question. Give example(s) of
(a) Hyperglycemic hormone and hypoglycemic hormone
(b) Hypercalcemic hormone
(c) Gonadotrophic hormones
(d) Progestational hormone
(e) Blood pressure lowering hormone
(f) Androgens and estrogens.

Answer. (a) Glucagon, insulin (b) Parathormone (PTH) (c) Follicle stimulating hormone (FSH) and luteinizing hormone (LH) (d) Progesterone (e) Atrial natriuretic hormone (f) Testosterone and estradiol

Question. What is exophthalmic goitre? Mention any four symptoms of this disorder. Answer. 

Answer. Exophthalmic goitre or Grave’s disease is caused due to hypersecretion of thyroid hormones. It is an autoimmune disease in which a person produces antibodies that mimic the action of TSH but are not regulated by normal negative feedback control. Its symptoms include protrusion of eye balls, loss of weight, rise in body temperature, rapid heart beat, nervousness and restlessness.

Question. How follicle stimulating hormone is different from luteinising hormone?

Answer. Differences between follicle stimulating hormone and luteinising hormone are: 

Question. Describe the functions of
(a) FSH,
(b) LH,
(c) LTH.

Answer. (a) FSH – In females it stimulates the development of ovarian follicle. In males it induces the development of seminiferous tubules and production of sperms. (b) LH – In females it regulates the formation of corpus luteum after ovulation and stimulates it to secrete progesterone. But in male it stimulates the interstitial cells of the testes to secrete testosterone hormone. (c) LTH – It promotes breast development to initiate the secretion of milk and also controls the secretion of progesterone by the corpus luteum.

Question. (a) Write the different types of cells of islets of Langerhans and also the hormones produced by them.
(b) How does anti-insulin hormone control glucose level in body?

Answer. (a) Islets of Langerhans of pancreas has four different kinds of cells: (i) a–cells - Produce glucagon (ii) b-cells - Produce insulin (iii) d-cells - Produce somatostatin (iv) Pancreatic polypeptide cells - Produce pancreatic polypeptide. (b) Glucagon is an anti-insulin hormone that stimulates the liver to convert stored glycogen into glucose in the blood. Low level of blood glucose stimulates secretion of glucagon and it signals the liver to release glucose into the blood. High blood glucose level suppresses release of glucagon and stimulates release of insulin.

Long Answer Type Questions

Question. (a) Which hormone is secreted by b-cells of pancreas? Also mention the location of b-cells.
(b) How does this hormone affect various processes in the body?
(c) Describe the disorders resulting from its deficient and excessive production.

Answer. (a) b-cells of pancreas secrete insulin hormone. These cells are usually found towards the middle of the islets of Langerhans. (b) Insulin converts glucose into glycogen in the liver and muscles. Insulin affects various processes in the body, such as : (i) It promotes protein synthesis in tissue from amino acids. (ii) It reduces catabolism of proteins. It is an anabolic hormone. (iii) It increases the synthesis of fat in the adipose tissue from fatty acids. (iv) Insulin reduces the breakdown and oxidation of fat. (c) Disorders of pancreas due to deficient and excessive production of insulin are : (i) Hyperglycemia or Diabetes mellitus : It is due to deficiency of insulin. It is of 2 types – The insulin-dependent diabetes mellitus (IDDM) is caused by a failure of the b-cells to produce adequate amount of insulin while the non-insulin-dependent diabetes mellitus (NIDDM) appears to involve failure of insulin to facilitate the movement of glucose into cells. In both disorders, the blood glucose concentration is elevated above the normal range. Some of the glucose is excreted in the urine and water follows the glucose, causing excessive urination and dehydration of body tissues. This causes excessive thirst (polydipsia). The cells are unable to utilise glucose and other carbohydrates for energy production and due to this reason they utilise their proteins for it. The person becomes very weak. Degradation of fats increases, producing ketone bodies (ketosis) that are acidic and poisonous. Blood cholesterol level rises and healing power is impaired. (ii) Hypoglycemia : It is due to excess of insulin or deficiency of glucagon, or a failure of the secretion of two hormones to completely regulate the blood glucose. The presence of excess insulin is more correctly referred to as hyperinsulinism. Its symptoms include weakness, profuse sweating, irritability, confusion, unconsciousness and convulsions, low blood glucose level, hunger. It needs urgent intake of sugar or glucose.

Chemical Co-Ordination And Integration

Questions. Why is oxytocin called as birth hormone? 

Ans1.It induces the vigorous contraction of the smooth muscles of the uterus that lead to the birth of the child.

Questions. What will happen if thyroxin is injected into a tadpole of frog? 

Ans2. It will quickly metamorphose into adult frog.

Questions. Why does the effect of noradrenalin last longer? 

Ans3. Since noradrenalin I s removed slowly from the blood as compared to adrenalin , it affects last longer.

Questions. Why is thymus called ‘throne of immunity ? 

Ans4. Since the T lymphocytes of immune system undergone maturation and proliferation in the thymus and contribute to the immunity of the body it is called throne of immunity.

Questions. Name the two hormone of hypothalamus that influences’ the middle lobe of pituitary. Mention their functions. 

Ans5. (1) Melanocytes stimulating –release hormone .Stimulate the function of MSH.
           (2) Melanocyte stimulating-inhibiting hormone.It inhibits the release of MSH.