Answer :
Answer:
(A) A reversal of the membrane polarity, with the interior of the cell becoming positively charged
Explanation:
Answer:
A. reversal of the membrane polarity, with the interior of the cell becoming positively charged.
Explanation:
- Nerve impulses are generated due to the reversal of the polarity between the intra and extracellular domains of the neural membrane.
- At rest, when no nerve impulse is traveling through the neuron, its membrane is at resting potential i.e. the outside of the membrane is positively charged due to abundance of sodium (Na+) ions.
- The inside of the membrane is negatively charged due to two reasons: 1. lesser concentration of cations (K+) inside the cell as compared to outside. 2. Abundance of chloride ions.
- At resting potential, the Na+/K+ pumps in the neuron membrane is closed, inhibiting the movement of these two ions.
- Upon arrival of a stimulus, these Na+/K+ pumps open, Na+ ions flood inside the cell, giving a positive charge to the inside of the membrane.
- Simultaneously, the K+ ions rush outside. Abundance of Cl- ions outside the cell gives the outer membrane a negative charge. These physiological changes generate an action potential that carries the nerve impulse forward.