Two categories of calcium are discernible: one tightly bound within bones and another more easily accessible type located on the bone surface.
The skeletal framework serves as a reservoir of minerals for the body, with 99% of the body's calcium stored in bones and teeth, providing structural support. The remaining 1% is dispersed in intracellular and extracellular fluids, allowing the body to draw from skeletal reserves during periods of low blood calcium levels and replenish them as necessary.
A continuous supply of calcium is vital throughout life, particularly during growth phases, pregnancy, and lactation (breastfeeding).
Calcium plays a pivotal role in the secretion of hormones and enzymes, facilitates the efficient functioning of neurotransmitters, and is indispensable for muscle and blood vessel contraction.
In the bloodstream, calcium concentration typically ranges from 2.25 to 2.5 mmol. Approximately 40-45% of this quantity binds to plasma proteins, 8-10% forms complexes with ions like citrate, and 45-50% exists as dissociated free ions.
Around 10-40% of dietary calcium is absorbed in the small intestine with the aid of vitamin D, and the body augments calcium absorption in the event of deficiency.
Calcium Importance and Absorption
