MUSCLE PHYSIOLOGY

Detailed explanation-1: -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-2: -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-3: -Inside the muscle fibre, the T-tubules lie next to the terminal cisternae of an internal membrane system derived from the endoplasmic reticulum, called the sarcoplasmic reticulum (SR), which is a store of calcium ions.

Detailed explanation-4: -Sarcoplasmic reticulum stores calcium ions and releases them into the sarcoplasm for the generation of action potential during muscle contraction. The binding of calcium ions to troponin removes the masking of active sites of myosin present on actin filaments.

Detailed explanation-5: -The sarcoplasmic reticulum in the muscle fibers resembles a network of smooth endoplasmic reticulums. This Sarcoplasmic reticulum functions as a storehouse of calcium iron. Calcium ions are important for the contraction and relaxation of muscles.