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

Thyrocalcitonin (also known as calcitonin) helps in the formation of osteoblasts. Osteoblasts are cells that synthesize bone and are crucial for bone growth and healing. Thyrocalcitonin lowers blood calcium levels by promoting the uptake of calcium into the bones.

Exophthalmic goiter, also known as Graves' disease, is caused by the over secretion of thyroid hormones (hyperthyroidism). This leads to symptoms such as protruding eyes (exophthalmos), increased metabolism, and enlarged thyroid gland (goiter).

Parathyroid hormone (PTH) and Thyrocalcitonin (TCT) together help regulate the calcium levels in the body. PTH increases blood calcium levels by promoting calcium release from bones, calcium absorption in the intestines, and calcium reabsorption in the kidneys. In contrast, TCT (calcitonin) lowers blood calcium levels by inhibiting bone resorption and promoting calcium deposition in bones.

Diabetes insipidus is a disorder caused by the deficiency of Antidiuretic Hormone (ADH). ADH helps the kidneys manage the amount of water in the body. When ADH levels are low, it leads to excessive urination and thirst, key symptoms of diabetes insipidus.

Thymosin is a hormone required for the differentiation of T-cells. T-cells are a type of white blood cell that play a central role in the immune response. Thymosin is produced by the thymus gland and is crucial for the maturation of T-cells.

Glucocorticoids are secreted by the Zona fasciculata, which is the middle layer of the adrenal cortex. These hormones are involved in the regulation of metabolism and immune response. Cortisol is one of the primary glucocorticoids produced in this layer.

To match the glands, hormones, and functions correctly, we need to understand the role of each gland and the hormone it secretes.

• The Posterior pituitary secretes Oxytocin, which is involved in milk secretion from the mammary gland.
• The Adrenal medulla secretes Catecholamines (like adrenaline), which cause pupillary dilation among other functions.
• The Parathyroid gland secretes PTH (Parathyroid Hormone), which increases Ca²⁺ absorption from digested food.
• The Ovary secretes Relaxin, which helps to relax the cervix of the uterus.
• The Adrenal cortex secretes Glucocorticoids, which regulate carbohydrate metabolism.

Thus, option o4 correctly matches these glands, hormones, and their functions.

During emergencies, the body's 'fight or flight' response is triggered, which involves the release of Adrenaline (also known as epinephrine) from the Adrenal medulla. This hormone prepares the body to respond to stressful situations by increasing heart rate, blood flow to muscles, and energy availability.

Mineralocorticoids, such as aldosterone, are secreted by the Zona glomerulosa of the adrenal cortex. These hormones are crucial for maintaining electrolyte balance and blood pressure by regulating sodium and potassium levels in the blood.

Diabetes mellitus is caused by the under secretion of insulin. Insulin is a hormone produced by the pancreas that helps to regulate blood sugar levels. When the body does not produce enough insulin, blood sugar levels remain high, leading to diabetes mellitus.