The terminal cisternae are parts of the

A) myofilaments.

B) sarcoplasmic reticula.

C) myofibrils.

D) I bands.

E) sarcolemma.

Sarcoplasmic reticula. (Ans. B)

Explanation:

Sarcoplasmic reticula is a network of membrane-bound structure abundant in muscle cells covering around the myofibrills. The main function of the sarcoplasmic reticula is to store a large amount of intracellular calcium (for muscle contraction) as well as transmitting the electrical impulse. When an action potential found, the signal reaches to the SR and release the stores of calcium ions. These ions will start the contraction of muscle cell & when the contraction is not needed, the SR will pump calcium ions back into the SR lumen for further use.

Terminal cisternae one of the enlarged area of the sarcoplasmic reticula of muscle cell covering the T-tubules.