MUSCLE PHYSIOLOGY

Detailed explanation-1: -Calcium ions at rest are stored in the sarcoplasmic reticulum (SR) from which they are rapidly released upon the depolarisation of the sarcolemmal and transverse (T-) tubular membranes of the muscle cell.

Detailed explanation-2: -The sarcoplasmic reticulum (SR) constitutes the main intracellular calcium store in striated muscle and plays an important role in the regulation of excitation-contraction-coupling (ECC) and of intracellular calcium concentrations during contraction and relaxation.

Detailed explanation-3: -When the muscle is stimulated, calcium ions are released from its store inside the sarcoplasmic reticulum, into the sarcoplasm (muscle ).

Detailed explanation-4: -The sarcoplasmic reticulum (SR) is a specialized form of the endoplasmic reticulum of muscle cells, dedicated to calcium ion (Ca2+) handling, necessary for muscle contraction and relaxation.

Detailed explanation-5: -About 99% of the body’s calcium is stored in bones, and the remaining 1% is found in blood, muscle, and other tissues. In order to perform these vital daily functions, the body works to keep a steady amount of calcium in the blood and tissues.