Hormone Functions and Regulation — NEET Biology

Correct answer: A — 1-a-i, 2-b-ii, 3-c-iii, 4-d-v, 5-e-iv

1. Thyroid gland secretes Thyrocalcitonin (TCT), which decreases blood calcium levels (1-a-i). "Thyroid gland also secretes a protein hormone called thyrocalcitonin (TCT) which regulates the blood calcium levels." (by decreasing it, implied by PTH's action). 2. Parathyroid gland secretes Parathyroid Hormone (PTH), which increases blood calcium levels (2-b-ii). "Parathyroid hormone (PTH) increases the Ca2+ levels in the blood." 3. Thymus gland secretes Thymosins, which promote T-lymphocyte differentiation (3-c-iii). "Thymosins play a major role in the differentiation of T-lymphocytes". 4. Adrenal medulla secretes Adrenaline, which increases heart beat and alertness (4-d-v). "These hormones increase alertness, pupilary dilation, piloerection (raising of hairs), sweating etc. Both the hormones increase the heart beat..." 5. Pancreas (α-cells) secretes Glucagon, which increases blood glucose levels (5-e-iv). "Glucagon acts mainly on the liver cells (hepatocytes) and stimulates glycogenolysis resulting in an increased blood sugar (hyperglycemia).". Option A correctly matches all these associations. This question integrates knowledge about various endocrine glands, their hormones, and their primary physiological effects.