Chemical Coordination and Control MCQs for NEET — Zoology Questions with Answers

The Juxta Glomerular Apparatus (JGA) secretes erythropoietin, a hormone that stimulates the formation of red blood cells (RBCs) in the bone marrow. This is crucial for maintaining adequate levels of RBCs and ensuring sufficient oxygen transport throughout the body.

T4, or Thyroxine, is not a secondary messenger. Secondary messengers are molecules that relay signals received by receptors to target molecules inside the cell. Examples include AMP (Adenosine Monophosphate), IP3 (Inositol Triphosphate), and Ca²⁺ (Calcium ions). Thyroxine is a primary hormone produced by the thyroid gland and does not function as a secondary messenger.

PTH, or Parathyroid Hormone, is called the hypercalcemic hormone because it increases the level of calcium in the blood. It does this by stimulating the release of calcium from bones, increasing the absorption of calcium in the intestines, and promoting the reabsorption of calcium in the kidneys. Thyroxine (o2) and TCT (Calcitonin, o3) are not involved in increasing blood calcium levels.

Cortisol and catecholamines (such as adrenaline and noradrenaline) are directly involved in cardiovascular activity. Cortisol helps regulate blood pressure and cardiovascular function, while catecholamines increase heart rate and blood pressure during stress responses. Insulin (o1), progesterone (o2), and oestrogen (o4) do not have direct roles in cardiovascular activity.

Estradiol is not a peptide/protein hormone. It is a steroid hormone, which belongs to the class of estrogens. On the other hand, Glucagon, Insulin, and FSH (Follicle Stimulating Hormone) are peptide/protein hormones.

Glucagon and insulin both require secondary messengers for their action. Glucagon uses cAMP as a secondary messenger, while insulin uses a signaling pathway involving insulin receptors and subsequent secondary messengers like PI3K and Akt.

Delta cells, also known as D cells, in the pancreas secrete somatostatin. Somatostatin acts to inhibit the release of both insulin and glucagon.

The ovaries secrete several hormones, including estrogen and relaxin. Estrogen is primarily responsible for the development of female secondary sexual characteristics and the regulation of the menstrual cycle. Relaxin is involved in the relaxation of the pelvic ligaments and cervix during childbirth.

The correct matching pairs are: (p-iii) Thymosin is involved in the differentiation of lymphocytes; (q-i) Glucocorticoids suppress the immune response; (r-iv) Deficiency of Iodine (Id₂d) leads to less BMR (Basal Metabolic Rate); (s-ii) Estrogen is associated with a high-pitched voice.

The hormones involved in carbohydrate metabolism include insulin, glucagon, glucocorticoids, and epinephrine. Insulin lowers blood glucose levels by promoting the uptake of glucose into cells. Glucagon increases blood glucose levels by stimulating the conversion of glycogen to glucose in the liver. Glucocorticoids, such as cortisol, promote gluconeogenesis, and epinephrine increases blood glucose levels by stimulating glycogenolysis.