Question

Which one of the following is called as a "homeostatic reservoir''?

• A. Cartilage
• B. Bone
• C. Blood
• D. All of the above

Answer 1

Answer: (B)

Bone

Bone is known as a homeostatic reservoir because it plays an important role in the calcium metabolism. It maintains the level of calcium in the blood under the influence of parathyroid hormone (PTH). The cells of the bone have the PTH receptors. In case of low calcium level in the blood, the parathyroid gland secretes PTH hormones which attach to the receptors of osteoblasts and stimulates to release the calcium ion from the bones to the blood. In case of high calcium level, the calcitonin hormone is released from the parafollicular cells of the thyroid gland which pushes the calcium ions from the blood to the bones and helps to maintain homeostasis.

So, the correct answer is option B.