Which gland secretes the most important hormone controlling calcium balance in the blood?

• A. Parathyroid gland
• B. Thyroid gland
• C. Adrenal gland
• D. Pituitary gland

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the role of calcium balance in the body. Calcium is essential for various physiological processes, including muscle contraction, nerve signaling, and blood clotting. Hormonal regulation ensures calcium levels remain within a narrow range.
2. Step 2: Identify the glands listed in the problem and their primary functions. For example: The parathyroid gland regulates calcium levels, the thyroid gland produces hormones like thyroxine and calcitonin, the adrenal gland secretes stress-related hormones, and the pituitary gland controls various endocrine functions.
3. Step 3: Focus on the parathyroid gland. It secretes parathyroid hormone (PTH), which is the most important hormone for controlling calcium balance in the blood. PTH increases blood calcium levels by stimulating bone resorption, enhancing calcium absorption in the intestines, and reducing calcium excretion by the kidneys.
4. Step 4: Compare the parathyroid gland's function to the thyroid gland, which secretes calcitonin. Calcitonin lowers blood calcium levels but plays a less significant role in calcium regulation compared to PTH.
5. Step 5: Eliminate the adrenal and pituitary glands as they do not directly regulate calcium balance. The adrenal gland primarily produces cortisol and adrenaline, while the pituitary gland controls other endocrine glands but does not directly influence calcium levels.