MUSCLE PHYSIOLOGY

Detailed explanation-1: -The action potential travels from the sarcolemma down a T-tubule and into the sarcoplasmic reticulum. As it does so, the release of calcium ions is stimulated from the terminal cisternae of the sarcoplasmic reticulum.

Detailed explanation-2: -The arrival of a nerve action potential at the axon terminal results in activation of voltage-gated calcium ion channels in the presynaptic membrane. The calcium influx initiates a calcium-dependent exocytosis of ACh-containing vesicles from the active zone of the presynaptic membrane.

Detailed explanation-3: -Answer and Explanation: The inward folds of sarcolemma are called b. t-tubules. Transverse tubules, or t-tubules, are responsible for carrying action potentials into the muscle to ensure that the entire muscle becomes depolarized and contracts as required.

Detailed explanation-4: -The correct answer to the question posed above is: A. T-tubules. Transverse tubules (T-tubules) are structural components of the cell. They are essentially invaginations of the muscle cell membrane that are able to penetrate deep towards the middle of different types of muscle cells.