AP Psychology Key Terms 1.3-1.4

Neuron – Nerve cell that sends signals.
Cell Body (Soma) – Holds nucleus, keeps cell alive.
Dendrites – Receive signals.
Axon – Sends signals away.
Myelin Sheath – Speeds signal travel.
Glial Cells – Support neurons.
Action Potential – Electrical signal down axon.
Threshold – Minimum stimulation to fire.
Refractory Period – Rest time after firing.
All-or-None Response – Fires fully or not at all.
Synapse – Gap between neurons.
Neurotransmitters – Chemical messengers.
Endorphins – Natural painkillers, boost pleasure.
Agonists – Mimic/enhance neurotransmitters.
Antagonists – Block neurotransmitters.
Endocrine System – Hormone system.
Hormones – Chemical messengers in blood.
Psychoactive Drug – Alters mood or behavior.
Substance Use Disorder – Harmful, uncontrollable drug use.
Depressants – Slow brain and body.
Tolerance – Need more for same effect.
Addiction – Compulsive use despite harm.
Withdrawal – Distress after stopping drug.
Barbiturates – Depressant, impair judgment.
Opioids – Pain relief, highly addictive.
Stimulants – Increase alertness and energy.
Hallucinogens – Distort perception.
Near-death Experience – Altered state near death.