AP Psychology Key Terms 1.3-1.4

Neuron

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

Cell Body (Soma)

The part of the neuron containing the nucleus that keeps the cell alive.

Dendrites

Extensions of a neuron that receive messages from other neurons.

Axon

A long fiber that sends electrical impulses away from the cell body.

Myelin Sheath

A fatty covering on the axon that speeds up neural transmission.

Glial Cells

Support cells that protect, nourish, and help neurons function.

Action Potential

A brief electrical impulse that travels down the axon when a neuron fires.

Threshold

The minimum stimulation needed to trigger an action potential.

Refractory Period

A short resting time after firing when a neuron cannot fire again.

All-or-None Response

The rule that a neuron either fires fully or not at all.

Synapse

The tiny gap between neurons where messages are passed.

Neurotransmitters

Chemical messengers that cross the synapse to send signals.

Endorphins

Natural neurotransmitters that reduce pain and increase pleasure.

Agonists

Chemicals or drugs that mimic or boost neurotransmitter effects.

Antagonists

Chemicals or drugs that block neurotransmitter effects.

Endocrine System

The body’s hormone system that sends messages through the bloodstream.

Hormones

Chemical messengers from glands that regulate growth, mood, and behavior.

Psychoactive Drug

A chemical substance that alters perceptions, mood, or behavior.

Substance Use Disorder

A pattern of drug use that causes significant impairment or distress, including cravings and inability to control use.

Depressants

Drugs that slow down the central nervous system, reducing neural activity and body functions.

Tolerance

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

Addiction

A compulsive craving for a substance or behavior despite harmful consequences.

Withdrawal

Discomfort and distress that follow when stopping the use of an addictive drug.

Barbiturates

Depressant drugs that slow the nervous system and can impair memory and judgment.

Opioids

Drugs (like heroin, morphine, codeine) that relieve pain and produce euphoria but are highly addictive.

Stimulants

Drugs that excite the nervous system, increasing alertness, mood, and energy.

Hallucinogens

Drugs that distort perceptions and create sensory experiences without real input.

Near-death Experience

An altered state of consciousness reported after close brushes with death, often involving visions or sensations.