Question

At the peak of the action potential:

a)voltage-gated K⁺ channels begin to close.

b)voltage-gated Na⁺ channels begin to close.

c)voltage-gated K⁺ channels begin to close, and voltage-gated Na⁺ channels begin to open.

d)voltage-gated K⁺ channels begin to open, and voltage-gated Na⁺ channels begin to close.

Answer 1

Answer.

Voltage gated K+ channels begin to open , and voltage gated N+ channels begins to close.

• At the peak of the action potential ~ 30mV the Na+ inactivation gate closes and the K+ activation gate opens. K+ will then diffuse down its concentration gradient out of the cell thus initiating the falling phase.
• When the potential reaches around the resting potential (~ -70mV), the K+ activation gate closes and the Na+ inactivation gate opens and the Na+ activation gate closes.
• Caused by K+ efflux