Chemical Coordination and Integration Test 17

In diabetes mellitus, a patient is unable to produce or utilise insulin hormone. This hormone helps in maintaining the level of glucose in the blood by converting extra glucose into glycogen. Thus, in diabetes mellitus, the body of the patient becomes incapable to store glucose in the form of glycogen. Therefore, he starts excreting glucose in the urine. If a patient kept on a carbohydrate-free diet is excreting glucose in the urine, then this means, high level of glucose in the blood not only depends on dietary carbohydrates but also on glycogenolysis (breakdown of glycogen into glucose in the liver) and gluconeogenesis(breakdown of fats into glucose in adipose tissues).

Adrenocorticotropic hormone is secreted by anterior pituitary. This hormone stimulates adrenal cortex to secrete its hormones.

Islets of Langerhans are found in pancreas. It consists of four types of cells - alpha cells that secrete glucagon, β-cells that secrete insulin, delta cells that secrete somatostatin and F cells that secrete pancreatic polypeptide.

Ovulation in females is under the control of luteinsing hormone (LH). Secreted by the anterior pituitary gland. It also stimulates development of corpus luteum.

Pineal body is a very small, reddish-grey, vascular, conical, solid body located in the brain. It secretes a hormone named melatonin. Melatonin makes the skin colour lighter in certain animals and also regulates the functioning of gonads, thus, controls sexual behaviour and regulates the period of puberty.

Goitre is caused due to the deficiency of iodine in the diet. Iodine is needed for the synthesis of thyroxine secreted by thyroid gland. The production of this hormone decreases with poor iodine diet. This causes enlargement of thyroid gland which is called goitre.

Insulin hormone produced by beta cells of pancreas, is central to regulating carbohydrate metabolism in the body. It causes cells in the skeletal muscles, and fat tissue to absorb glucose from the blood.

Thymus gland is a prominent gland at birth but gradually atrophies in the adult. It is a soft, pinkish, bilobed mass of lymphoid tissue. It secretes a hormone thymosin which is involved in producing immunity.

Calcitonin is a hormone secreted by the thyroid gland. It lowers the calcium level in the blood by suppressing the release of calcium ions from the bones.

Adrenal gland secretes adrenaline, and emergency hormone, therefore it is also called emergency gland of the body.

Thyroid stimulating hormone (TSH) is produced by the anterior lobe of the pituitary and it stimulates production and secretion of thyroid hormones.

Calcium plays an important role in blood clotting. Parathormone, a hormone released by parathyroid glands, increases calcium level in the blood. Therefore, deficiency of this hormone will decrease Ca²⁺ level in blood, thus leading to delay in blood clotting and increase in bleeding time.

Estrogen, secreted by ovaries in females, stimulates the development of secondary sexual characters during puberty and maintains them through the reproductive years of adult life in females Testosterone is produced by testes in males, it stimulates the development of male secondary sexual characters like beard, moustache, etc.

Somatostatin is an inhibitory hormone which is secreted by hypothalamus in the brain and pancreas. Somatostatin from hypothalamus inhibits the secretion of growth hormone from the anterior lobe of pituitary. Somatostatin from pancreas inhibits the release of other hormones from pancreas like insulin and glucagon.

Growth hormone secreted by the anterior pituitary has a widespread effect in the body it stimulates growth of various body cells, promotes protein anabolism, absorption of calcium from bowel and conversion of glycogen to glucose.

Feedback control is a mechanism by which secretion of hormones is under the control of factors or other hormones. When the level of epinephrine decreases in the blood, it stimulates the hypothalamus to secrete more CRH which results in increased production of ACTH from anterior lobe of pituitary which in turn stimulates the increased production of epinephrine from adrenal medulla.

Aldosterone (secreted by adrenal medulla) acts mainly on the renal tubules and stimulates the reabsorption of Na⁺ and water and excretion of K⁺ and phosphate ions.

When secretion of hormones is under the control of factors or other hormones, it is called the feedback control. If the level of progesterone and estrogen is low in the blood, it stimulates the hypothalamus to secrete more FSH-RH which results in increased production of FSH from anterior pituitary which in turn stimulates the increased secretion of estrogen and progesterone from ovary.

Hormones of testes and gonads are steroid in nature. They are derived from cholesterol.

Growth hormone(GH) secreted by anterior pituitary promotes cell division, protein synthesis and bone growth.