While it's relatively common knowledge that calcium is an important mineral in the human diet, and plays an important part in maintaining the health of the skeletal system, the exact role of calcium in skeletal organization is not as commonly understood. In fact, calcium is not simply an ingredient in bone, but bones store calcium for other functions, as well.
Significance
The skeletal system is essential to human function for a variety of reasons. First, muscles attach to bones, and while the muscles produce movement, the skeletal system is their foundation for doing so. Without a strong skeletal system, the body couldn't move. Additionally, strong bones provide protection for delicate internal organs such as the brain, lungs, heart, and reproductive organs. A strong skeleton is crucial to life and health.
Function
The role of calcium in the skeletal system is twofold. Humans need to maintain strong bones in order to maintain a strong and functional skeletal system, and calcium is an important part of the bone matrix. Explains Dr. Lauralee Sherwood in her book "Human Physiology," the human skeleton is made up of about one third cartilaginous tissue called chondroitin sulfate and about two thirds bony salts called hydroxylapatite. The bony salts have the chemical formula Ca5(PO4)3OH.
Considerations
The skeletal system isn't the only of the body's organ systems that uses calcium, however. The muscles, including the heart, rely upon calcium signals to initiate and maintain contraction. As such, calcium in the bloodstream is important to both muscular and cardiovascular function, and the body works hard to maintain a constant level of calcium in the blood. Notes Dr. Gary Thibodeau in his book "Anatomy and Physiology," the skeleton acts as a "warehouse" for calcium.
Calcium Storage
In order to maintain constant levels of calcium in the blood, body hormones can either add calcium to or remove it from bone matrix, as needed. Parathyroid hormone from the parathyroid gland in the neck pulls calcium from the bones to increase blood calcium, notes Dr. Thibodeau, while calcitonin from the thyroid gland adds calcium to bones to decrease blood calcium. Though calcium is crucial to skeletal integrity as well as to muscle function, the body prioritizes blood calcium above skeletal calcium.
Expert Insight
Certain factors can decrease the amount of available calcium in the bloodstream, and may cause the body to pull large amounts of calcium from the bones. In extreme cases and over time, this can lead to weakening of the bone matrix known as osteoporosis. Explains Dr. Sherwood, females are more susceptible to osteoporosis than males, since they have less bone density to begin with. Aging individuals are also more susceptible, since calcium consumption and absorption from the gut tend to decrease with age.
References
- "Human Physiology"; Lauralee Sherwood, Ph.D.; 2004
- "Anatomy and Physiology"; Gary Thibodeau, Ph.D.; 2007
Member Comments