MEDICAL PHYSIOLOGY

Detailed explanation-1: -An excitatory postsynaptic potential (EPSP) occurs when sodium channels open in response to a stimulus. The electrochemical gradient drives sodium to rush into the cell. When sodium brings its positive charge into the cell, the cell’s membrane potential becomes more positive, or depolarizes.

Detailed explanation-2: -Would the opening of a Na+ channel lead to an EPSP or an IPSP? Opening an Na+ channel will lead to an EPSP because Na+ would rush into the cell, depolarizing it, and creating a voltage that is above threshold and producing an AP.

Detailed explanation-3: -Sodium channels mediate fast depolarization and conduct electrical impulses throughout nerve, muscle and heart.

Detailed explanation-4: -They occur in all types of neurons in both the myenteric and submucosal plexuses (Fig. 5). All of the fast EPSPs in the small and large intestine and stomach appear to be mediated by acetylcholine acting at nicotinic postsynaptic receptors.

Detailed explanation-5: -Excitatory postsynaptic potentials (EPSPs) are associated with transmitter-induced increase in Na+ and K+ conductance of the synaptic membrane, resulting in net entry of positive charge carried by Na+ and membrane depolarization.