Calcium salts form the bulk of the inorganic material in bone. What is the function of the calcium salts?
The Correct Answer and Explanation is:
Correct Answer:
The function of calcium salts in bone is to provide hardness and strength.
Explanation (300+ words):
Calcium salts, primarily in the form of calcium phosphate (hydroxyapatite crystals), make up approximately 65-70% of the inorganic matrix of bone tissue. These mineral salts are critical for giving bone its rigid and durable structure, which supports the body, protects internal organs, and facilitates movement by acting as levers for muscle action.
The main role of calcium salts is to harden the bone. Without these salts, bones would be soft and pliable, much like cartilage. This hardness enables bones to withstand compressive forces and support the body’s weight during various activities such as standing, walking, and lifting. The hydroxyapatite crystals are embedded within a collagen matrix; while the collagen fibers provide tensile strength and flexibility, the calcium salts provide compressive strength, allowing bones to resist being crushed.
In addition to structural support, calcium in bones serves as a reservoir for calcium ions in the body. Calcium plays essential roles in numerous physiological processes including blood clotting, nerve conduction, muscle contraction, and enzyme activity. When blood calcium levels drop, bone is broken down (resorbed) by osteoclasts, releasing calcium ions into the bloodstream to maintain homeostasis. Conversely, when calcium levels are high, the body can deposit calcium into the bone for storage.
This dynamic balance of bone deposition and resorption is regulated by hormones such as parathyroid hormone (PTH), calcitonin, and vitamin D. These regulatory systems ensure that the skeleton remains strong while also maintaining critical calcium levels in the blood and tissues.
In summary, calcium salts provide the hardness, strength, and mineral reservoir function of bones. They are essential for both the mechanical integrity of the skeletal system and the physiological balance of calcium in the human body.