Question

Which one of the following hormones increases the blood calcium levels ?

• A. Adrenaline
• B. Growth hormone
• C. Thyroxine
• D. Parathyroid hormone

Answer 1

The correct option is D Parathyroid hormone

The parathyroid glands secrete a hormone called parathyroid hormone (PTH). When the blood calcium level decreases, the parathyroid gland releases the parathyroid hormone. PTH acts on bones and stimulates bone resorption to release calcium ions into the blood. PTH also stimulates the reabsorption of $C{a}^{2+}$ by the renal tubules and increases $C{a}^{2+}$ absorption from the digested food. Thus, PTH increases the blood calcium levels.

Adrenaline is secreted by adrenal glands. It is an emergency hormone and is secreted when the body is in a stressful situation.

Growth hormone is secreted by the pituitary gland. It stimulates growth and cell reproduction.

Thyroxine is secreted by the thyroid gland. It plays an important role in the regulation of the basal metabolic rate.