Final answer:
There is indeed an after-hyperpolarizing phase following the repolarizing phase of an action potential, characterized by an overshoot of the membrane potential below the resting level due to delayed closure of potassium channels.
Step-by-step explanation:
Yes, there is an after-hyperpolarizing phase that follows the repolarizing phase. After the peak action potential, repolarization occurs as K+ (potassium ions) begin to leave the cell. This process serves to return the membrane potential towards the resting level of approximately -70 mV. However, due to the delayed closure of K+ channels, the membrane potential transiently becomes more negative than the resting potential, resulting in a period of hyperpolarization. This after-hyperpolarization ensures that potassium ions reach equilibrium when the membrane voltage is below the resting potential, leading to a brief overshoot below -70 mV and preventing immediate re-firing of the neuron.