8.1 Role of calcium in the human body
8.2 Calcium requirements
8.3 Regulation of calcium metabolism in the body
8.4 Calcium deficiency in the body
8.5 Elevated calcium content in the body
Control questions Situational tasks
Calcium is a trace element involved in the building of bones, cardiac function, neuromuscular activity, blood coagulation and many other processes. Calcium metabolism is closely related to the skeletal system and the functioning of the parathyroid glands.
Content in the body. The greater portion of calcium (about 99%) is found in bones (from 1 to 2.2 kg in young people and 0.5 kg in the elderly) in the form of apatites and carbonates, which form the basis of the human skeleton. Of the remaining 1% of calcium most of it is intra-cellular, and a very small amount is extracellular (10 mg dl, 5 mEq/l.2.5 mM/l). Calcium in the blood serum: 50% in a free (ionized) state, 40% in a protein bound, 10% as a part of compounds with phosphate, citrate, bicarbonate and lactate.
Measuring the level of ionized calcium allows establishing a connection between the certain pathological signs and impaired calcium metabolism.
8.1. Role of calcium in the human body
The role of calcium in the physiological processes of the human body: structural (essential for bones, teeth), signal (intracellular secondary messenger intermediary), enzymatic (coenzyme of coagulation factors), con-
jugation of neuromuscular excitation and contraction (controling excitability, isolation of neurotransmitters, initiation of muscle contraction), conjugation of excitation andsecretion (regulating hormone secretion), affecting water exchange, normalizing the carbohydrate and sodium chloride metabolism, reducing the level of vascular wall permeability, producing an anti-inflammatory effect, participating in maintaining the acid-base balance in the body.