Excitability of cells is maximally affected
by change in concentration of which
ion?
a) IC+
b) Na*
c) a-
d) Ca+2
Correct Answer - D
Ans. D. Ca+2
[Ref Principles of medical physiology p.801]
Effects of ion concentration change on membrane potential:
- Hypercalcemia
- An increase in extracellular Ca2+ concentration can stabilize the
membrane by decreasing excitability.
- Hypocalcemia
- Calcium ion is membrane stabilizers.
- A decrease in extracellular Ca2+ concentration increases the
excitability of nerve by decreasing the amount of depolarization
necessary to produce the action potential. - Hyperexcitability is seen