Final answer:
Bones help regulate blood calcium levels, important for muscle contractions and nerve impulses. The endocrine system, including the parathyroid glands, monitors these levels closely to prevent hypocalcemia or hypercalcemia.
Step-by-step explanation:
Bones play a crucial role in regulating blood calcium levels, vital for maintaining normal physiological functions such as muscle contraction and membrane potentials. Calcium ions are indispensable for various bodily processes, including muscle contractions, nerve impulse transmission, blood clotting, and more. The bones act as a reservoir, storing calcium and releasing it into the bloodstream as needed to preserve homeostasis. The endocrine system, particularly the parathyroid glands, tightly regulates blood calcium levels. Dysregulation can lead to either hypocalcemia, which can cause muscle spasms and convulsions, or hypercalcemia, which can lead to decreased membrane responsiveness and lethargy.