What two events render a segment of an axon temporarily insensitive or refractory to another stimulus?

Absolute refractory period

Relative refractory period

Explanation:

While an action potential is in progress, another one cannot be initiated. That effect is referred to as the refractory period. There are two phases of the refractory period: the absolute refractory period and the relative refractory period. During the absolute phase, another action potential will not start. This is because of the inactivation gate of the voltage-gated Na+ channel. Once that channel is back to its resting conformation (less than -55 mV), a new action potential could be started, but only by a stronger stimulus than the one that initiated the current action potential. This is because of the flow of K+ out of the cell. Because that ion is rushing out, any Na+ that tries to enter will not depolarize the cell, but will only keep the cell from hyperpolarizing.

between the two muscle layers is the myenteric or auerbach's plexus, which controls peristalsis. in the colon, the muscularis externa is much thicker because the feces are large and heavy, requiring more force to push along. the stomach has a third layer of muscularis externa: the inner oblique layer.

explanation:

for example, code 28039 - excision, tumor, soft tissue of foot or toe, subcutaneous, 1.5 cm or greater, appears before 28043 - excision, tumor, soft tissue of foot or toe, subcutaneous; less than 1.5 cm.