AP PSYCH NEURONS

Dendrites

a neuron’s branching extensions that receive messages and conduct impulses toward the cell body

axon

the neuron extension that passes messages through its branches to other neurons or to muscles or glands (electrical message travels the length of)

Myelin sheath

a fatty tissue layer segmentally encasing the axons of some neurons; enables vastly greater transmission speed as neural impulses hop from one sausage-like node to the next

action potential

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

Refractory Period

“repolarized”; a period of inactivity after a neuron has fired

Threshold

the level of stimulation required to trigger a neural impulse

all-or-none response

a neuron’s reaction of either firing (with a full-strength response) or not firing at all

Synapse

junction between the axon tip of the sending neuron and the dendrite or cell body of receiving neuron

Neurotransmitters

chemical messages that cross the synaptic gaps between neurons

• travel across the synapse and bind to receptor sites on the receiving neuron

  • influencing whether that neuron will generate a neural impulse

Reuptake

a neurotransmitter’s reabsorption by the sending neuron