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.

a less-active, mature cell in areolar connective tissue would be a:

a. fibroblast

b. fibrocyte

c. chondroblast

d. chondrocyte