Question

Suppose you inject K⁺ ions into an individual, which dramatically increases extracellular K⁺ concentration so that the K⁺ equilibrium potential is about -20 mV. How might this affect resting membrane potential? How do you think this would affect a neuron’s ability to generate action potentials?

Answer 1

Ans:-

a) affect on RMP

Resting membrane potential will become less negative. For eg rmp will shift from -90 mv to -60 mv.

This occurs because negative charge of rmp is generated by outflux of K + ion . Now as conc of K is high outside the cell so less k+ will go out of cell and more k+ will stay inside the cell. And as k+ is positively charge it will decrease the negativity of rmp.

b) In this situation neuron will become hyperexcitable . Because rmp has reached close to threshlod potential . A little stimulus can shift RMP to threshold potential leading to firing of neuron.

for eg if threshold potential is -50 mv . And rmp has changed from -90 to -60 mv then there is just diff of 10mv between threshold potential and rmp . So neuron will become more excitable.