Neuroscience: Neuron Structure, Function, and Neurotransmitters

Axon

the extension of a neuron, ending in branching terminal fibers, through which messages pass to other neurons or to muscles or glands

Dendrites

a neuron's bushy, branching extensions that receive messages and conduct impulses toward the cell body

myelin sheath

covers the axon of some neurons and helps speed neural impulses

Multiple Sclerosis (MS)

destruction of the myelin sheath on neurons in the CNS and its replacement by plaques of sclerotic (hard) tissue

Dopamine

A neurotransmitter associated with movement, attention and learning and the brain's pleasure and reward system.

Serotonin

A neurotransmitter that affects hunger,sleep, arousal, and mood.

Norepinephrine

A neurotransmitter that helps control alertness and arousal

Acetylcholine (ACh)

A neurotransmitter that enables muscle action, learning, and memory

GABA

a major inhibitory neurotransmitter

Glutamate

A major excitatory neurotransmitter; involved in memory

Endorphins

natural, opiate-like neurotransmitters linked to pain control and to pleasure

Agonist

a molecule that increases a neurotransmitter's action

Antagonist

a molecule that inhibits or blocks a neurotransmitter's action

SSRI

class of drugs used to relieve anxiety by limiting reuptake of the neurotransmitter serotonin

threshold

the level of stimulation required to trigger a neural impulse

refractory period

a period of inactivity after a neuron has fired

All of None Response

a neuron's reaction of either firing (with a full-strength response) or not firing.

synapse

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

Action Potential

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

Reflex Arc

the nerve pathway involved in a reflex action including at its simplest a sensory nerve and a motor nerve with a synapse between.