- Exam
- NEET
- Subject
- Zoology
- Chapter
- Neural Control and Coordination
NEET · Zoology · Neural Control and Coordination
What is the resting potential of the plasma membrane of a neuron?
Options
- AThe electrical potential difference across the resting plasma membrane when the membrane is in a polarised state.
- BThe electrical potential difference across the plasma membrane when the neuron is conducting an impulse.
- CThe electrical potential difference across the plasma membrane when the membrane is in a depolarised state.
- DThe electrical potential difference across the plasma membrane when the membrane is in a non-polarised state.
Correct answer
A. The electrical potential difference across the resting plasma membrane when the membrane is in a polarised state.
Step-by-step solution
The outer surface of the axonal membrane possesses a positive charge while its inner surface becomes negatively charged and therefore is polarised The sodium-potassium pump transports 3 Na⁺ ions outwards for 2 K⁺ ions into the cell. When a stimulus is applied at a site on the polarised membrane, the membrane at the site A becomes freely permeable to sodium ions (Na⁺), leading to an influx of Na⁺ and a reversal of the polarity at that site.The action potential of the plasma membrane of a neuron is the electrical potential difference across the plasma membrane.The rise in permeability to Na⁺ is short-lived and is followed by a rise in permeability to K⁺. K⁺ diffuses outside the membrane, restoring the resting potential of the membrane.