MUSCLE PHYSIOLOGY

Detailed explanation-1: -Cell membrane depolarization is stimulated by nerve impulses arriving at the neuromuscular junction. Following the generation of a sufficient motor endplate potential, depolarization occurs along the sarcolemmal membrane.

Detailed explanation-2: -Activation of the nAChR leads to an influx of cations (sodium and calcium) that causes depolarization of the muscle cell membrane. This depolarization in turn activates a high density of voltage-gated sodium channels on the muscle membrane, eliciting an action potential.

Detailed explanation-3: -In neurons, the rapid rise in potential, depolarization, is an all-or-nothing event that is initiated by the opening of sodium ion channels within the plasma membrane. The subsequent return to resting potential, repolarization, is mediated by the opening of potassium ion channels.

Detailed explanation-4: -Cell depolarization leads to glutamate release into the synaptic cleft through calcium-mediated exocytosis. Excessive extracellular glutamate binds to receptors on adjacent cells.