EPSP

[Miracoli]

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The drawing below shows the excitatory postsynaptic (end plate) potential (EPP) of the neuromuscular junction as a function of time. The rising phase of the EPP is caused by ACh molecules binding to their receptors. The falling phase of the EPP potential (region between the two arrows) is caused by:

A) the activity of Na+, K+-ATPase
B) the opening of voltage-gated Cl− channels
C) the opening of voltage-gated K+ channels
D) Movement of Na+ into the cell
E) the closure of resting Na+ channels
F) the closure of Cl− channels

 

[ulikedaggers]

C

 

[Miracoli]

AA is correct.
---after an EPSP graded potential, the membrane potential is brought back from the subthreshold depolarization to RMP by Na-K ATPase
--after an action potential, the membrane potential is brought back from hyperpolarization to RMP by Na-K ATPase
---after an IPSP graded potential, the membrane potential is brought back from the hyperpolarization to RMP by Na-K ATPase

 

[syma]

I am going with C. The sodium pump has hardly any role in repolarising a cell.

 

[Miracoli]

I am going with C. The sodium pump has hardly any role in repolarising a cell.

Read about the maintenance of RMP and effect of inhibition of Na-K pump