Q. During repolarisation of nerve
A) $K^{+}\ gate\ close\ and\ Na^{+}gate\ opens$
B) $Na^{+}$channels are close and$\ K^{+}\$channels are opens
C) Both gates remain open
D) Both $K^{+}and\ Na^{+}$ gates are close
Explanation
During repolarization, $Na^{+}$ channels are closed. Actually, it occurs due to depolarization, so that no more $Na^{+}$ ions can enter the cell. After about 0.5 ms, permeability to $K^{+}$ ion increases because the build up of positive charge inside the cell opens voltage-gated $K^{+}$ channels.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.