Steps in which a presynaptic neuron signals a postsynaptic neuron

step 1

action potential arrives at axon terminal

step 5

binding of neurotransmitter opens ion channels, resulting in graded potentials.

step 3

ca+ entry causes synaptic vesicles to release their neurotransmitters by exocytosis

step 4

neurotransmitter diffuses across synaptic cleft and binds to specific receptors on the postsynaptic membrane

step 6

neurotransmitter effects are terminated

step 2

voltage gated ca+ channels open. ca+ enters axon terminal