Figure 12-2 The Nerve Action Potential

Use Figure 12-2 to answer the following questions:
-What is occurring in the area between #2 and #3?
A) An excitatory graded potential is occurring.
B) Potassium ions are entering the axon and causing depolarization.
C) Chemically gated sodium channels are open and sodium is diffusing into the axon.
D) Sodium ions are entering the axon and causing depolarization.
E) Repolarization of the axon due to sodium ions leaving the axon is occurring.

Question

Figure 12-2 The Nerve Action Potential
 
Use Figure 12-2 to answer the following questions:
-What is occurring in the area between #2 and #3?
A) An excitatory graded potential is occurring. 
B) Potassium ions are entering the axon and causing depolarization. 
C) Chemically gated sodium channels are open and sodium is diffusing into the axon. 
D) Sodium ions are entering the axon and causing depolarization. 
E) Repolarization of the axon due to sodium ions leaving the axon is occurring.

Quizplus · Accepted Answer

Sodium ions are entering the axon and causing depolarization, as indicated by the steep rising portion of the action potential between #2 and #3.

Figure 12-2 the Nerve Action Potential