Which two hormones regulate blood calcium levels, and which glands secrete them?

• A. Insulin from the pancreas and glucagon from the pancreas
• B. Aldosterone from the adrenal glands and antidiuretic hormone from the pituitary gland
• C. Calcitonin from the thyroid gland and parathyroid hormone from the parathyroid glands
• D. Thyroxine from the thyroid gland and cortisol from the adrenal glands

Answer: (C)

Verified step by step guidance

1. Identify the primary function of blood calcium regulation in the body, which is crucial for maintaining bone health, nerve function, and muscle contraction.
2. Understand that two key hormones are involved in regulating blood calcium levels: Calcitonin and Parathyroid Hormone (PTH).
3. Calcitonin is secreted by the thyroid gland and works to lower blood calcium levels by inhibiting osteoclast activity, which reduces the release of calcium from bones.
4. Parathyroid Hormone (PTH) is secreted by the parathyroid glands and increases blood calcium levels by stimulating osteoclasts to release calcium from bones, enhancing calcium reabsorption in the kidneys, and promoting the activation of vitamin D to increase calcium absorption in the intestines.
5. Recognize that other hormones mentioned, such as insulin, glucagon, aldosterone, antidiuretic hormone, thyroxine, and cortisol, have different roles in the body and do not directly regulate blood calcium levels.