Given below are the steps involved in the generation and conduction of nerve impulse. Arrange them in proper sequence and select the correct option. I . Rapid influx of N a + ions followed by reversal

Question

Given below are the steps involved in the generation and conduction of nerve impulse. Arrange them in proper sequence and select the correct option.

$I .$ Rapid influx of ${N a}^{+}$ ions followed by reversal of polarity at the site of application of stimulus.
$I I .$ Reversal of polarity and generation of action potential at a point ahead of the point of application of stimulus.
$I I I .$ Development of free permeability to ${N a}^{+}$ ions at the site of application of stimulus.
$I V .$ Arrival of the impulse generated at the first site to the second site.
$V .$ Rise in permeability of $K^{+}$ ions and restoration of the resting potential of the membrane.

TestHub · Accepted Answer

The sequential order of the generation and conduction of nerve impulse is as follows:

$1 .$ As soon as stimulus is applied at a site, (site A) the site becomes freely permeable to ${N a}^{+}$ ions.

$2 .$ This causes a rapid influx of ${N a}^{+}$ ions intracellularly. This causes a reversal of polarity i.e. the intracellular surface acquires a positive charge and the extracellular surface acquires a negative charge.

$3 .$ At a site ahead of the first site (site B), the extracellular surface has a positive and the intracellular surface has a negative charge. Thus, extracellularly, the current flows from site B to site A and intracellularly, it flows from site $A$ to site $B$ to complete the circuit. This causes a reversal of polarity at site $B$ .

$4 .$ The impulse generated at site A is transmitted to site $B$ .

$5 .$ The stimulus induced permeability to $N a^{+}$ ions disappears very quickly. The $K^{+}$ ions are diffused outside the cell and the resting potential of the membrane is restored.

Zoology - Neural Control and Coordination Question with Solution | TestHub

Options:

Doubts & Discussion