Question

1. List the hormones released from the following glands and their action. Some secrete more than 1 type of hormone.
   1. Pineal gland
   2. Thyroid gland
   3. Parathyroid glands
   4. Thymus
   5. Adrenal cortex
   6. Adrenal medulla
   7. Pancreas

Answer 1

a)Pineal gland secretes serotonin derived hormone called melatonin which regulates the biological clock cycle
It is inhibited by light and triggered by darkness
Its action is to maintain the sleep and wake cycles.

b)Thyoid has 2 hormones- Triiodothyronine (T3) and thyroxine (T4) they affect metabolic rate and regulate body functions like breathing,temperature,heart rate etc.
Calcitonin is produced by thyroid gland,for regulating levels of calcium and phosphate in blood.

c)Parathyroid hormone produces calcitriol (1.25 OH vit D3) which increases the tubular reabsorption of calcium from the glomerular filtrate leads to prevention in calcium loss in urine .

d)Thymus gland produce several hormones like
Thymopoeitin and thymulin which assists in the process of differentiation of T cell
Thymosin that stimulates immune response as well as hormones like growth hormones
Thymic humoral factor which increase the immune response to virus.
It also canproduce hormones like insulin and melatonin because it have epithelial cells on its surface which other receptors can work.

e)Adrenal cortex produces
1.mineralocorticoids:it helps to maintain body salt and water level,which regulates blood pressure.
Among them,most jmportant is aldosterone
2.Glucocorticoids:Mainly cortisol, it is involved in response to illness and regulate metabolism.It also promote the production of glucose for energy and also has anti inflammatory effect
3:Adrenal androgens:male sex hormones mainly DHEA and testosterone
Role in early development of male sex organs in childhood and female body hair in puberty.

f)Adrenal medulla-produces catecholamines
Catecholamine include adrenaline,noradrenaline and small amounts of dopamine. These hormones are responsible for all physiological characteristics of the stress response called fight or flight response.

g)Pancreas secretes hormones like
1.Gastrin: helps in digestion by stimulating certain cells in the stomach to produce acid.

2.Glucagon: helps insulin to maintain normal blood glucose by working in the opposite way of insulin and also stimulates cells to release glucose and raises blood glucose levels.

3.Insulin: regulates blood glucose by allowing many of body’s cells to absorb and use glucose leads to decrease in blood glucose .

4.Somatostatin: When levels of other pancreatic hormones like insulin and glucagon, get too high, somatostatin is secreted to maintain a balance of glucose and salt in the blood.

5.Vasoactive intestinal peptide (VIP): This hormone helps control water secretion and absorption from the intestines by stimulating the intestinal cells to release water and salts into the intestines.