NEET Practice Questions (MCQs) with Answers & Solutions

Parathyroid glands, which are located near the thyroid gland, regulate calcium (Ca²⁺) levels in the blood. Surgery on the thyroid gland can sometimes inadvertently damage the parathyroid glands, leading to irregularities in calcium levels. Thus, both statements x and y are correct, and y provides a correct explanation for x.

In cases of thyroid cancer, hyperthyroidism is often observed, which means an increased rate of thyroid hormone synthesis and secretion. Therefore, both statements x and y are correct, and y provides a correct explanation for x.

Over secretion of the adrenal cortex, particularly the zona reticularis, results in the increased production of androgenic steroids. This can lead to the development of male secondary sexual characteristics such as facial hair in females, a condition known as hirsutism. Therefore, both statements x and y are correct, and y provides the correct explanation for x.

Insulin facilitates the uptake of glucose by cells, particularly hepatocytes (liver cells), muscle cells, and adipose tissue. This reduces the level of glucose in the blood. Hence, both statements x and y are correct, and y correctly explains why x happens.

Hormones exert their effects by binding to specific receptors on or in their target organs. If these receptors are removed, the target organ will not be able to respond to the hormone because the signaling pathway is disrupted. Thus, the correct option is that the target organ will not respond to the hormone.

The adenohypophysis (anterior pituitary) secretes Somatotropin (growth hormone), the adrenal medulla produces epinephrine, the parathyroid gland secretes Calcitonin, and the thymus gland secretes Thymosin. Therefore, the correct matching is (p: ii), (q: i), (r: iv), (s: iii).

Sodium (Na+) is not a second messenger in hormone action. Second messengers like cGMP, Calcium (Ca²⁺), and cAMP are molecules that relay signals received at receptors on the cell surface to target molecules inside the cell.

Ledyigs cells produce Testosterone, Hyperthyroidism does not cause Tetany (which is related to low calcium and parathyroid function), Adenohypophysis (anterior pituitary) releases ACTH, and Dwarfism is related to Growth Hormone (GH) deficiency. Therefore, the correct matching is (p - iv) (q - i) (r - iii) (s - ii).

The menstrual cycle in human beings is primarily controlled by the hormones FSH (Follicle Stimulating Hormone), LH (Luteinizing Hormone), and Estrogen. FSH and LH are produced by the pituitary gland and play crucial roles in the regulation of the menstrual cycle, including the maturation of ovarian follicles and ovulation. Estrogen is produced by the ovaries and is important for the development of the uterine lining.

Adenohypophysectomy, the surgical removal of the anterior pituitary gland, affects several hormonal regulations. One of the major impacts is on the Basal Metabolic Rate (BMR) because the anterior pituitary produces Thyroid Stimulating Hormone (TSH), which stimulates the thyroid gland to produce hormones that regulate metabolism. Without TSH, the thyroid gland's function is impaired, leading to a decrease in BMR.