Depolarization and EPSPs

what opens ligand-gated channels

a ligand, usually a transmitters

what happens when neurotransmitter opens a sodium-permeable channel;?

sodium enters the neuron

what happens when positive sodium enters a negative neuron?

the membrane becomes less negative

what is depolarization?

making the membrane potential less negative

is depolarization excitatory or inhibitory?

excitatory

what is an EPSP?

excitatory postsynaptic potential

what does an EPSP do?

it moves the neuron closer to firing an action potential

why does one EPSP often not fire the neuron?

it may be too small alone to reach threshold

what determines whether a neuron fires?

the combined effect of many excitatory and inhibitory inputs