Which gland's regulation affects blood calcium levels?

Which gland's regulation affects blood calcium levels?

• A. Adrenal
• B. Parathyroid
• C. Pineal
• D. Thymus

Answer: (B)

Calcium balance in the blood is tightly controlled by the parathyroid glands through parathyroid hormone (PTH). When blood calcium drops, these glands release PTH, which raises calcium by three main actions: stimulating bone to release calcium into the bloodstream, increasing calcium reabsorption in the kidneys to reduce urinary loss, and promoting the activation of vitamin D, which enhances calcium absorption from the gut. While calcitonin from the thyroid can lower calcium when levels are high, the parathyroid glands are the primary regulators that adjust calcium levels in response to low calcium. The adrenal, pineal, and thymus glands do not play the central role in maintaining blood calcium the way the parathyroid glands do.

Calcium balance in the blood is tightly controlled by the parathyroid glands through parathyroid hormone (PTH). When blood calcium drops, these glands release PTH, which raises calcium by three main actions: stimulating bone to release calcium into the bloodstream, increasing calcium reabsorption in the kidneys to reduce urinary loss, and promoting the activation of vitamin D, which enhances calcium absorption from the gut. While calcitonin from the thyroid can lower calcium when levels are high, the parathyroid glands are the primary regulators that adjust calcium levels in response to low calcium. The adrenal, pineal, and thymus glands do not play the central role in maintaining blood calcium the way the parathyroid glands do.