Final answer:
The correct chronological order of events during an Action Potential is: depolarization to threshold, opening of Na+ channels, Na+ influx, closing of Na+ channels, K+ efflux (repolarization), and closing of K+ channels, represented by option a) 1, 2, 3, 4, 5, 6.
Step-by-step explanation:
When placing the events of an Action Potential in the correct chronological order, a sound understanding of the physiological processes involved is essential. The sequence begins with the Depolarization of the membrane to threshold, which is the initial change towards the threshold potential due to a stimulus. Next, Opening of voltage-gated Na+ channels occurs, allowing Na+ to flow into the cell and causing the Depolarization phase. This influx of Na+ raises the membrane potential. The sequence continues with the Closing of Na+ channels and the opening of K+ channels, initiating the Repolarization phase, with K+ exiting the cell. Lastly, the Closing of K+ channels occurs, leading to the resting potential being re-established by the Na+/K+ pump. Therefore, the correct order of these events is: (1) Depolarization of membrane to threshold, (2) Opening of voltage-gated channels, (3) Depolarization phase (Na+ Influx), (4) Closing of Na+ channels, (5) Repolarization phase (K+ efflux), (6) Closing of K+ channels, which corresponds to option a) 1, 2, 3, 4, 5, 6.