Questions -  Answers

Very Short Answer Type Questions 
1. What is acromegaly? Name the hormone responsible for this disorder.
A: a. The disorder resulted due to hypersecretion of somatotropin in adults is known as acromegaly (elongation of bones of jaws, hand and feet, thickened nose, wide finger tips etc.,
     b. Over secretion of pituitary hormone, namely somatotropin.
 

2. Which hormone is called anti diuretic hormone? Write the name of the gland secretes it.
A: a. Vasopressin
     b. Neurohypophysis of pituitary gland.
 

3. Name the gland increases in size during childhood and decreases in size during adulthood. What important role does it play in case of infection?
A: a. Thymus gland
    b. Thymosins secreted by thymus gland play important role in maturation of T - cells, that provide cell mediated immunity in case of infections.
 

4. Distinguish between diabetes incipidus and diabetes mellitus.
A: a. The disorder resulted due to deficiency of vasopressin is known as diabetes  incipidus, which is characterised by loss of water through urine (diuresis).
     b. The disorder resulted due to deficiency of insulin is known as diabetes mellitus, which is characterised by loss of glucose through urine (glucosuria).
 

5. What are islets of langerhans?
A: The endocrine cells of pancreas are known as islets of langerhans. They are of four types.
   a. α - cells - secrete glucagon
   b. β - cells - secrete insulin
   c. D - cells - secrete somatostatin
   d. F - cells - secrete pancreatic polypeptide
 

6. What is insulin shock?
A: Over secretion or over doses of insulin leads to fall in blood glucose level(hypoglycemia) resulting in insulin shock.
 

7. Which hormones are commonly known as fight and flight hormones?
A: Adrenalin and noradrenalin
 

8. What are androgens? Which cells secrete them?
A: a. The male sex hormones are known as androgens (e.g.: testosterone)
     b. Leydig cells/ interstitial cells of testes.
 

9. What is erythropoietin? What is its function?
A: a. The hormone produced by kidney is known as erythropoietin.
     b. Enythropoietin stimulates the erythropoiesis (formation of RBC)


Short Answer Type Questions
1. Give an account of secretions of pituitary gland.
A: Hormones secreted by adenohypophysis
Growth hormone (GH)/ Somatotropin: It mainly stimulates the cells of liver to secrete insulin like growth factors. They cause elongation of bones by stimulating cell division in epiphyseal plates. They promote growth by promoting cell division, differentiation and accelerating protein synthesis and decrease catabolism of proteins.
Thyroid stimulating Hormone (TSH)/ Thyrotropin: It stimulates the synthesis and secretion of hormones from thyroid gland.
Adreno Cortico Tropic Hormone (ACTH): It controls the synthesis and secretion of steroid hormones like glucocorticoides by cortex of adrenal gland.
Follicle Stimulating Hormone (FSH): It promotes the growth of ovarian follicles in female. In males it regulate the spermatogenesis. 
Luteinising Hormone (LH): In males it is called interstitial cell stimulating hormone (ICSH) that stimulates the leydig cells of testes to secrete androgens (like testosterone). In females stimulates the process of ovulation. It also maintains corpus luteum. LH also stimulate ovaries to secrete oestrogens and progesterone.
Prolactin/ Lactogenic hormone/ Luteotropic Hormone: It causes the enlargement of mammary glands. It also helps in maintaining corpus luteum of the ovary to maintain pregnancy.
Pars intermedia: It secrets Melanocyte Stimulating Hormone (MSH). Its role is insignificant in man.
Hormones secreted by neurohypophysis: It stores and releases two hormones vasopressin and oxytocin (These are actually secreted by hypothalamus).
i. Vasopressin: It stimulates the reabsorption of water by the distal convoluted tubule and collecting duct of renal tubule. Vasopressin is also called Anti Diuretic Hormone (ADH).
ii. Oxytocin induces the contraction of smooth muscles. In female it cause powerful contractions of uterine muscles during child birth and ejection of milk by milk glands.

2. Describe the role of hypothalamus as a neuro-endocrine organ.
A: The floor of diencephalon is the thalamus. Below the thalamus, is the hypothalamus. It connect the neural and endocrine systems. It is closely associated with the pituitary. Hypothalamus contains groups of neurosecretory cells (called nuclei). They secrete neurohormones. They are carried to the neurohypophysis through axons of hypothalamo hypophyseal tract. Neurohormones are of two types, namely, releasing hormones
stimulate secretion of pituitary hormones) and inhibiting hormones (inhibit secretions of pituitary hormones).
e.g.: i. Growth hormone releasing hormone (somatocrinin) stimulates the synthesis and release somatotropin by pituitary.
       ii. Growth hormone inhibiting hormone (somatostatin) secreted by hypothalamus inhibits the release of growth hormone from pituitary.
 

3. Compare a pituitary dwarf and a thyroid dwarf in respect of similarities and dissimilarities they possess. 

A: 

4. Explain how hypothyroidism and hyperthyroidism can affect the body.
A: * Hyperthyroidism causes exopthalmia (protruded eye balls), increased metabolic rate etc.,
* Deficiency of iodine in the diet results in hypothyroidism and enlargement of thyroid (simple goitre).
* Hypothyroidism during pregnancy leads to cretinism of the developing baby. Cretin suffers from stunted growth, mental retardation, low IQ, abnormal skin, deafness, mutism etc.
* Hypothyroidism in adults results in myxedema (low metabolic rate, lethargy, puffiness of skin and face, dry skin etc., are its main symptoms).
 

6. Write notes on Addison's disease and Cushing's syndrome.
A: * Hyposecretion of glucocorticoids leads to Addison's disease. It is characterised by loss of weight, muscle weakness, fatigue reduced blood pressure, brozening of skin etc.,
* Hypersecretion of glucocorticoids leads to Cushing's syndrome. It is characterised by break down of muscle proteins, redistribution of body fat, moon face, buffalo hump and wound healing is poor, obesity etc.,
 

7. Why does sugar appear in urine of a diabetic?
A: * Beta cells of Pancreas secrete insulin. It makes the cell membranes more permeable to absorb glucose from blood. As a result, blood glucose level decreases. Hence, insulin is known as hypoglycemic hormone. It also accelerates glycogenesis, lipogenesis; enhances uptake of amino acids by cells and inhibits catabolism of proteins.
* Hyposecretion of insulin results in rise in blood glucose level (hyperglycemia). Prolonged hyperglycemia leads to diabetes mellitus. Which is characterised by glucosuria (loss of glucose through urine) and formation of ketone bodies. To control diabetes mellitus, insulin therapy is in practice.
 

8. Describe female sex hormones and their actions.
A: In females, there is a pair of ovaries located in abdomen behind the kidneys. Ova are developed from the ovarian follicles. In addition, ovaries secrete oestrogen and progesterone. Oestrogen is responsible for development of secondary sexual characters (development and maturation of female sex organs, mammary glands, high pitch voice (feminine) etc.,) in female. Progesterone prepare the uterus the development of embryo and maintains pregnancy.

9. Write note on the mechanism of action of hormones.
A: Hormones are circulated to all parts of the body through blood circulation. But the hormones affects only specific target cells by binding to specific proteins called hormone receptors. located in the target cells only. (Receptors of target cell membrane are called membrane bound receptors and those present in the cell are called intracellular receptors). Hormone receptors are specific for each of hormone. Hormone along with its receptor form a hormone receptor complex. It generates biochemical changes in the target cells.
i. Hormone (generally water soluble) with membrane bound receptor do not enter the target cell, but produce second messengers. They regulate cellular metabolism in cascading action amplifying the final effect.
ii. Hormones which interact with intracellular receptors (e.g.: steroid hormones) are fat soluble and diffuse into the cytoplasm of target cell through plasma membrane. They bind to internal receptors, enter the nucleus and regulate gene expression.