MUSCLE PHYSIOLOGY

Detailed explanation-1: -Sarcoplasmic reticulum is a network of specialized smooth endoplasmic reticulum that is necessary for transmitting electrical impulses and also stores calcium ions. The muscle cells are rich in smooth endoplasmic reticulum so they are known as sarcoplasmic reticulum (membrane-bound structure rich in muscle cells).

Detailed explanation-2: -High concentrations of calcium in skeletal muscle are stored in a specialized type of smooth endoplasmic reticulum organelle called the sarcoplasmic reticulum (SR). The SR structure surrounds the myofibrils, allowing storage and release of calcium directly at sites of actin and myosin overlap.

Detailed explanation-3: -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-4: -Sarcoplasmic reticulum stores calcium ions and releases them into the sarcoplasm for the generation of action potential during muscle contraction.

Detailed explanation-5: -Calcium ion release from the SR, occurs in the junctional SR/terminal cisternae through a ryanodine receptor (RyR) and is known as a calcium spark.