31 Years NEET Previous Year Questions:Chemical Coordination And Regulation - 3 - NEET MCQ

Insulin decreases the level of glucose in the blood while cortisol (secreted by middle region of adrenal cortex) increases the blood-glucose level by converting proteins and fats into carbohydrates which are, in turn, converted to glucose.

In 1912, Gudernatsch discovered that metamorphosis in frog’s tadpole is controlled by the thyroxine hormone which has the iodine as the main constituent. If thyroxin or iodine is added in water having tadpoles in it, then it increases the rate of metamorphosis in tadpole.

Insulin is a hormone secreted by the b-cells of pancreas and it controls the sugar level in blood

Leydig’s cells are present in testes and they secrete male hormone testesterone.
Small groups of polygonal, large cells present in the connective tissue in between the seminiferous tubules are known as Leydig’s cells are interstitial cells. They secret male sex hormone testosterone

ADH : Antidiuretic hormone – vasopressin in secreted  by neurohypophysis (posterior lobe) of pituitary gland. This hormone increases the reabsorption of water from the urine and hence urine gets concentrated and ECF gets diluted. Diabetes insipidus caused by the hyposecretion of ADH.

Enterogastrone secreted by the mucosa of duodenum slows gastric contractions and stops the secretion of gastric juice.

Leydig’s cells.

Male hormones are secreted by the Interstitial or Leydig’s cells present in the stroma of connective tissue in between the seminiferous tubules in testis. They produce androgens (mainly testosterone) Sertoli cells are elongated epithelial cells present inside the seminal vesicle to nourish the growing spermatozoa.

Luteinizing Hormone (LH) induces the Leideyg’s cells in males to produce testesterone and in female it causes ovulation and secretion of female sex hormone estrogen from mature ovarian follicle & progesterone by corpus luteum.

Enterogastrone is a hormone released by the upper intestinal mucosa that inhibits gastric orotility and secretion.motility and secretion.

Ovulation occurs under the influence of luteinizing hormone-LH secreted by the anterior lobe of pituitary.

 Mammalian corpus luteum produces progesterone. It is essential for the continuation of pregnancy and it also stimulates acini glands.

Nicotine and acetylcholine have the same receptors-Nicotinic cholinergic receptors and hence have the same action. 

The thyroid gland stores its hormone secretion thyroglobulin in its follicles called extracellular space before discharing it into the blood.

 The hormones in blood act on specific sites or receptors of target organ. So if we remove the receptor molecule from the target organs, there will be no response.

Iodine is an element used by thyroid gland for the synthesis of thyroid hormones. Thus radioactive isotope Iodine -131 is used as radioactive material for detection of thyroid cancer.

Prolactin is a proteinaceous hormone released by anterior lobe of pituitary. Prolactin supplements the action of gonadal hormones in stimulating the growth and activity of female mammary gland during  pregnancy and lactation. Oxytocin released by the posterior lobe of pituitary gland, is important for the mechanism of ejection of milk from the mammary glands due to sucking of breasts by infant. Progesterone, released by corpus luteum  brings about pregnancy changes such as uterine growth, implantation of embryo etc. Relaxin  is a proteinaceous hormone secreted by corpus luteum towards the end  of gestation period for loosening and softening of pelvic ligaments, relaxing of uterus for easing parturition.

According  to the immunity theory ageing occurs due to the loss of power of defence against the invasion of germs and pathogens. The process starts with the gradual atrophy and disappearance of the thymus gland during middle age.

Oxytocin also known as pitocin. It is an important hormone which is released in neurohypophysis of pituitary. It stimulate the contraction of smooth muscles. It stimulate labour pain and also increase labour pain. It is a hormone for quick birth. 1Its more secretion results in parturition. 

The amino acid glycine forms porphyrin ring in chlorophyll and haeme proteins like haemoglobin. Tryptophan gives rise to plant hormone indole- 3 - acetic acid.

Calcitonin  is a polypeptide hormone which lowers calcium and phosphate level of plasma by inhibiting  bone degradation and stimulating their uptake by bone parathyroid  harmone elevates calcium level in blood.

Use of contraceptive pills is a wide spread form of birth control. contraceptive pills contain estrogen and progesterone. The production of the pituitary hormones FSH & LH in the normal sexual cycle of a female is shut down by these hormones. In the absence of FSH, the ovarian follicles  do not ripe and ovulation does not occur in the absence of LH.

Parathormone released by the parathyroid gland  elevates the level of  Ca2⁺ in blood. The deficiency of this hormone lowers blood Ca2^+. As a  result,  the excitability of muscles and nerves increases producing tetany -sustained contraction.

Oxytocin is also called the ‘child birth hormone’. Prolactin helps in lactation. Luteinizing hormone levels trigger ovulation.