part 5: neuronal signaling Human anatomy and physiology

a ligand-gated channel

An ion channel that is stimulated to open by the binding of a small molecule such as a neurotransmitter.

voltage gated channels

Ion membrane channels that open and close in response to changes in membrane potential.

action potential

a neural impulse; a brief electrical charge that travels down an axon

Depolarization

change in a cell membrane potential from rest toward zero

Hyperpolarization

change in cell membrane potential below resting potential (<-70mV)

Neurotransmitters

chemical messengers that cross the synaptic gaps between neurons

membrane potential

distribution of charge across the cell membrane, based on the charges of ions

leakage channels

ion channel that opens randomly and is not gated to a specific event, also known as a non-gated channel

mechanically gated channels

ion channel that opens when a physical event directly affects the structure of the protein

Repolarization

return of the membrane potential to its normally negative voltage at the end of the action potential

resting membrane potential

the electrical charge of a neuron when it is not active