Anatomy and Physiology I
BSC 1085C Ref# 82458
Calcium plays a very significant role in our bodies. Approximately 99 percent of the calcium in our bodies is stored in the teeth and bones. Calcium generates about two percent of our total body weight. Calcium is crucial in bone formation, keeping strong bones and teeth and is known for helping to prevent osteoporosis. Although calcium is mostly thought about in the bones and teeth, it also plays important roles throughout the body. The amount of calcium outside the bones and teeth may be small in comparison to what is inside the bones and teeth, but is very useful in many functions in the body. Calcium is required in functions such as the contraction and relaxation of muscles. This helps in keeping a regular heartbeat. Calcium is also used in clotting of the blood and the transfer of nerve impulses. Calcium is also an influential player in exocytosis and it helps in the regulation of enzyme activity. Calcium can affect the use of other nutrients in the body and how they are absorbed. It can also aid in disease prevention and lowering blood pressure in cases where individuals have high blood pressure. (Kamps, 2012; UMMC, 2011).
There are three hormones that are responsible for maintaining calcium homeostasis in the body. They are the parathyroid hormone, vitamin D and calcitonin. Parathyroid is the main hormone involved in regulating calcium levels. There are four parathyroid glands which lie posterior to the thyroid glands. The cells in the parathyroid gland act in response to the calcium levels in the blood. When the calcium levels are low the cells increase the release of the parathyroid hormone. The parathyroid hormone raises blood calcium levels by triggering the kidneys to raise calcium reabsorption and upregulating enzymes in the kidney that change vitamin D to its activated form. This increases calcium intake in the intestine and resorption from the bone. When...
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