MUSCLE PHYSIOLOGY

Detailed explanation-1: -T-tubules are invaginations of the plasma membrane, which are present exclusively in striated muscle. Their role is to maintain the SR calcium store under the tight control of membrane depolarization via the voltage sensor channel DHPR [2].

Detailed explanation-2: -Transverse (T)-tubules invaginate the sarcolemma, allowing impulses to penetrate the cell and activate the SR.

Detailed explanation-3: -The T-tubules carry the action potential into the interior of the cell, which triggers the opening of calcium channels in the membrane of the adjacent SR, causing Ca++ to diffuse out of the SR and into the sarcoplasm.

Detailed explanation-4: -Electrical signals travel along the neuron’s axon, which branches through the muscle and connects to individual muscle fibers at a neuromuscular junction.