Zoology MCQs for NEET — Practice Questions with Answers

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.

The immediate cause of induction of ovulation in the human female is the large plasma surge of Luteinizing Hormone (LH). This surge triggers the release of the mature egg from the ovarian follicle, a process known as ovulation. The LH surge is a critical event in the menstrual cycle and is often used as a marker for predicting ovulation.

Glucagon and insulin are hormones that are secreted by the pancreas but from different types of cells. Insulin is secreted by the beta cells of the islets of Langerhans, while glucagon is secreted by the alpha cells. They have opposite effects on blood glucose levels: insulin lowers blood glucose levels, while glucagon raises them.

Enterogastrone is a hormone secreted by the mucosa of the small intestine in response to the presence of fatty acids. It inhibits the secretion of gastric juice and slows down the process of gastric emptying, allowing more time for the digestion and absorption of fats.

Heavy jaws, long face, and long extremities are characteristic features of acromegaly, which is caused by the over secretion of growth hormone from the anterior lobe of the pituitary gland after puberty. This condition leads to the abnormal growth of bones and tissues.

FSH (Follicle-Stimulating Hormone) and LH (Luteinizing Hormone) are collectively referred to as Gonadotropins or Gonadotropic Hormones (GTH). These hormones are secreted by the anterior pituitary gland and play a crucial role in regulating the reproductive processes in both males and females.

Calciferol is another name for Vitamin D. A deficiency in Vitamin D can lead to Rickets, a condition characterized by weakened or softened bones in children. This occurs due to impaired bone mineralization, which is essential for healthy bone development.