Question

Injection of potassium into the post-synaptic neuron will decrease the size of the EPP

BECAUSE
The higher intracellular potassium will raise the resting membrane potential
a. TRUE and TRUE
b. TRUE and FALSE
c. FALSE and TRUE
d. FALSE and FALSE

Answer 1

Injection of potassium into the post-synaptic neuron will decrease the size of the EPP, which is TRUE. However, increasing intracellular potassium levels will raise the resting membrane potential, making it more difficult for the neuron to generate an action potential, which is FALSE.

Step-by-step explanation:

The correct option is b. TRUE and FALSE.

Injection of potassium into the post-synaptic neuron will decrease the size of the excitatory postsynaptic potential (EPP). The higher intracellular potassium will raise the resting membrane potential.

However, raising the resting membrane potential makes it more difficult for the neuron to reach the threshold potential required for an action potential to occur.

To explain this further, the resting membrane potential is usually around -70mV, and an action potential is triggered when it reaches the threshold potential of around -55mV.

Increasing the intracellular potassium concentration will make the resting membrane potential more positive, let's say to -65mV.

This means the neuron would need to depolarize by another 10mV to reach the threshold potential, making it more difficult to generate an action potential.