If a person has low calcium for many years, how would you expect their body to respond?

• A. The intestines would decrease calcium absorption.
• B. The bones would lose density since calcium is pulled from the bones.
• C. The kidneys would become calcified from filtering out excessive calcium.
• D. They thyroid would release excess calcitonin leading to hypothyroidism.

Answer: (B)

Verified step by step guidance

1. Understand the role of calcium in the body: Calcium is essential for bone health, muscle function, nerve signaling, and blood clotting. The body tightly regulates calcium levels in the blood to ensure these functions are maintained.
2. Recognize the body's response to low calcium levels: When calcium intake is insufficient over a long period, the body compensates by pulling calcium from the bones to maintain blood calcium levels. This process is regulated by hormones such as parathyroid hormone (PTH).
3. Analyze the impact on bone health: Since calcium is being removed from the bones, this leads to a decrease in bone density over time, a condition known as osteoporosis or osteopenia.
4. Evaluate the role of the kidneys and intestines: The kidneys do not become calcified in this scenario, as they are not filtering out excessive calcium. Instead, the kidneys may work to conserve calcium by reducing calcium excretion in urine. The intestines may increase calcium absorption if vitamin D levels are adequate, as vitamin D enhances calcium absorption.
5. Clarify the role of the thyroid: The thyroid gland releases calcitonin, a hormone that lowers blood calcium levels by inhibiting bone resorption. However, in the case of low calcium levels, the parathyroid gland, not the thyroid, is more active, releasing PTH to increase blood calcium. Hypothyroidism is unrelated to this process.