PATHOLOGY

Detailed explanation-1: -Intracellular calcium concentrations are maintained at least four orders of magnitude lower than that of extracellular calcium. This gradient makes calcium an exceptionally effective intracellular signaling molecule. Plasma membrane voltage-gated calcium channels comprise a significant mechanism for calcium signaling.

Detailed explanation-2: -The concentration of calcium in the intracellular fluid (ICF) is 10, 000 times less that that in the ECF. Depending on the cell type, the calcium concentration in ICF is∼50–200 nmol/l (138).

Detailed explanation-3: -Intracellular calcium can be raised via calcium entry from the extracellular space or calcium release from the intracellular organelles. The level of membrane potential and the activity of various ionic pumps and channels are essential elements in the control of calcium homeostasis.