A nerve cell that transmits information using electrical and chemical signals.

Cells that support, insulate, and protect neurons.

The negative charge inside a neuron when it is not firing.

The critical point a stimulus must reach to trigger a neuron to fire.

The process where the inside of a neuron becomes positive during an action potential.

A short rest period after firing when a neuron cannot fire again.

The reabsorption of neurotransmitters to end the signal and prepare for the next one.

Chemical messengers that relay signals between neurons.

Chemical messengers produced by glands that travel through the bloodstream.

Substances that mimic or enhance neurotransmitter effects.

Substances that block neurotransmitter effects.

The need for higher doses of a drug to achieve the same effect.

Symptoms that occur when stopping drug use.

Resting potential, threshold, all-or-nothing principle, depolarization, refractory period, reuptake.

Sensory neurons detect stimulus, interneurons relay signal in spinal cord, motor neurons cause muscle reaction.

Agonists mimic or enhance neurotransmitter effects, while antagonists block them.

Stimulants increase neural activity, while depressants decrease it.