Question

Which of the following is incorrect for generation and conduction of nerve impulse?

• A. Ionic gradients across the resting membrane are maintained by the active transport of ions by the sodium-potassium pump
• B. When a stimulus is applied at a site on the polarised membrane, the membrane at the site becomes freely permeable to Na+
• C. During conduction of impulse, the axon membrane has a negative charge on the outer surface and positive charge on its inner surface
• D. <!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> The rise in the stimulus-induced permeability to Na+ is extremely shortlived which is quickly followed by a rise in permeability to K+.

Answer 1

The correct option is C During conduction of impulse, the axon membrane has a negative charge on the outer surface and positive charge on its inner surface

Ionic gradients across the resting membrane are maintained by the active transport of ions by the sodium-potassium pump which transports 3 Na+ outwards for 2 K+ into the cell resulting in positive charge in outer surface and negative charge in inner surface and therefore polarised.

When a stimulus is applied at a site on the polarised membrane, the membrane at the site becomes freely permeable to Na+ which leads to a rapid influx of Na+ followed by the reversal of the polarity at that site.

During conduction of nerve impulse, the axon membrane has a positive charge on the outer surface and a negative charge on its inner surface which results a current flows from + to - direction.

The rise in the stimulus-induced permeability to Na+ is extremely shortlived which is quickly followed by a rise in permeability to K+.