The Action Potential

What is the resting membrane potential (RMP) of a neuron?

-70 mV

What occurs when a depolarizing stimulus reaches -55 mV?

Voltage-gated Na+ channels open.

What happens during depolarization?

Na+ moves into the cell, making the membrane potential more positive.

At the peak of the action potential, what happens to VG Na+ channels?

They close while VG K+ channels are fully open.

What is hyperpolarization?

A membrane potential that is more negative than the resting membrane potential.

What are graded potentials?

Local potentials that diminish with time and distance.

Where do graded potentials occur in a neuron?

In the dendrites or soma (cell body).

What causes graded potentials?

Opening of ligand-gated channels on the post-synaptic membrane.

What is temporal summation?

Multiple graded potentials occur at once within a single neuron due to high frequency of APs from the presynaptic neuron.

What is spatial summation?

Multiple graded potentials occur at once from multiple presynaptic neurons.