Final answer:
The time a neuron must wait after an action potential before it can fire again is known as the refractory period, which includes the absolute and relative phases. It is crucial for resetting the neuron's ion channels and for proper signal transmission.
Step-by-step explanation:
After a neuron experiences an action potential, it must wait for 1 or 2 milliseconds before it can fire again. This period of time is called the refractory period. The refractory period consists of two phases: the absolute refractory period and the relative refractory period. During the absolute refractory period, another action potential cannot be initiated due to the inactivation gate of the voltage-gated Na+ channel. Only once this channel returns to its resting conformation can a new action potential potentially be initiated, and even then, it requires a stronger stimulus due to the continuous outflow of K+ ions from the cell.
The function of the refractory period is crucial as it allows the voltage-sensitive ion channels to return to their resting configurations. The sodium potassium ATPase helps in restoring the resting potential by moving Na+ out of the cell and K+ into the cell, setting up the neuron for subsequent action potentials. Without this refractory period, neurons would not be able to regulate the timing of action potentials, and effective signal transmission would be compromised.