Question

An action potential is self-regenerating because __________.

(a) Depolarizing currents established by the influx of K+ flow down the axon and trigger an action potential at the next segment
(b) Depolarizing currents established by the influx of Na+ flow down the axon and trigger an action potential at the next segment

Answer 1

An action potential is self-regenerating because depolarizing currents established by the influx of Na+ flow down the axon and trigger an action potential at the next segment.

Step-by-step explanation:

An action potential is self-regenerating because (b) depolarizing currents established by the influx of Na+ flow down the axon and trigger an action potential at the next segment.

During an action potential, the membrane depolarizes as sodium ions rush into the cell, causing a change in the membrane potential. This depolarization spreads down the axon due to Na+ channels opening and allowing Na+ ions to enter the next segment of the axon, initiating another action potential.

Meanwhile, the first part of the membrane repolarizes as potassium ions leave the cell. However, the Na+ channels are inactivated and additional K+ channels have opened, preventing the membrane from depolarizing again and allowing the action potential to propagate in one direction.