Arrange the steps in generation and conduction of nerve impulses in the correct sequence. A. The number of positive ions inside the axon increases. B. Axoplasm becomes negatively charged and ECF becom

Question

Arrange the steps in generation and conduction of nerve impulses in the correct sequence.
A. The number of positive ions inside the axon increases.
B. Axoplasm becomes negatively charged and ECF becomes positively charged.
C. Membrane potential changes from resting potential to action potential.
D. Membrane becomes more permeable for $Na^{+}$
E. $Na^{+}$ channels close and $K^{+}$ gates open and K diffuses out of the axon.
Select the correct answer from the options.

TestHub · Accepted Answer

When a stimulus is applied at a site on the polarized membrane, the membrane becomes freely permeable to $Na^{+}$ (D).

This leads to a rapid influx of $Na^{+}$ , which increases the number of positive ions inside the axon (A).

The rapid influx of $Na^{+}$ causes depolarization, and the membrane potential changes from resting potential to action potential (C).

Within a fraction of a second, the $Na^{+}$ channels close and $K^{+}$ gates open, allowing $K^{+}$ to diffuse out of the axon (E).

The efflux of $K^{+}$ restores the resting membrane potential, causing the axoplasm to become negatively charged and the extracellular fluid (ECF) to become positively charged again (repolarization) (B).

The correct sequence is D $\to$ A $\to$ C $\to$ E $\to$ B.

Answer: D $\to$ A $\to$ C $\to$ E $\to$ B

Biology - Neural Control and Coordination Question with Solution | TestHub

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