Unit 1: The Neuron, Neural Firing, Neurotransmitters, and Psychoactive Drugs

A detailed vocabulary flashcard set covering neurons, neural transmission, neurotransmitters, hormones, and psychoactive drugs based on AP Psychology Unit 1 lecture notes.

Neurons

Specialized cells that transmit electrical signals and carry out most of the brain's communication.

Glial Cells

Support cells in the brain that protect, nourish, and clean up after neurons to maintain their functioning environment.

Cell Body (Soma)

The neuron's control center that houses the nucleus and produces energy for the cell.

Dendrites

The receiving structures of a neuron that listen for incoming signals from other neurons.

Axon

The single long extension of a neuron that sends outgoing signals to other neurons or muscles.

Myelin Sheath

A fatty layer wrapped around the axon that speeds up the transmission of electrical signals.

Synapse

The small gap between neurons where communication occurs via chemical messengers known as neurotransmitters.

Central Nervous System (CNS)

The division of the nervous system consisting of the brain and spinal cord that processes information and controls actions.

Peripheral Nervous System (PNS)

The network of nerves outside the central nervous system that transmits signals to and from the CNS.

Reflex Arc

An automatic, rapid response to a stimulus that bypasses the brain to allow instant physical reactions.

Action Potential

A brief electrical charge that travels down a neuron's axon when triggered by reaching a threshold.

All-or-Nothing Principle

The principle stating that a neuron either fires completely or does not fire at all.

Depolarization

The shift in a neuron's electrical charge becoming less negative, which leads to neural firing.

Refractory Period

The brief period after a neuron fires during which it must reset before it can fire again.

Resting Potential

The state of a neuron when it is fully prepared to fire an electrical impulse but has not yet been triggered.

Neurotransmitters

Chemical messengers released into the synaptic gap to transmit signals between neurons.

Excitatory Neurotransmitters

Neurotransmitters that encourage neurons to fire action potentials.

Dopamine

An excitatory neurotransmitter involved in regulating reward, pleasure, and motivation.

Norepinephrine

An excitatory neurotransmitter that arouses mental alertness, focus, and energy.

Glutamate

The most common excitatory neurotransmitter in the brain, heavily linked to learning and memory.

Substance P

A neurotransmitter released by sensory neurons in response to injury or stress that transmits pain signals to the brain and promotes inflammation.

Inhibitory Neurotransmitters

Neurotransmitters that prevent neurons from firing.

GABA

The primary inhibitory neurotransmitter that calms and slows down central nervous system activity.

Serotonin

An inhibitory neurotransmitter that plays a crucial role in regulating mood, emotion, and sleep.

Endorphins

Natural inhibitory neurotransmitters produced by the brain that relieve pain and reduce emotional stress.

Multiple Sclerosis (MS)

A disorder characterized by damage to the myelin sheath surrounding axons, which slows down or blocks neural signals.

Myasthenia Gravis

An autoimmune disorder in which acetylcholine receptors on muscle cells are attacked and blocked, leading to muscle weakness.

Endocrine System

A slow chemical communication system consisting of glands that secrete hormones directly into the bloodstream.

Hormones

Chemical messengers secreted by endocrine glands that travel through the bloodstream to influence behavior, mood, and organ function over longer periods.

Adrenaline

An endocrine hormone that increases heart rate and energy levels to prepare the body for a fight-or-flight response.

Oxytocin

A hormone that influences social bonding, trust, and interpersonal behaviors.

Leptin

A hormone secreted by fat cells that regulates hunger signals and fat storage.

Melatonin

A hormone secreted by the pineal gland that regulates sleep-wake cycles.

Ghrelin

A hormone produced in the gastrointestinal tract that stimulates appetite and hunger.

Psychoactive Drugs

Chemical substances that alter brain function, resulting in temporary changes in perception, mood, consciousness, or behavior.

Agonists

Drugs that mimic or enhance the activity of specific neurotransmitters by binding to their receptor sites.

Antagonists

Drugs that block or inhibit neurotransmitter activity by occupying receptor sites without activating them.

Reuptake Inhibitors

Drugs that prevent presynaptic neurons from reabsorbing neurotransmitters from the synaptic cleft, thereby prolonging neurotransmitter action.

Stimulants

A class of psychoactive drugs that speed up body functions and central nervous system activity by boosting dopamine, norepinephrine, and serotonin levels.

Caffeine

The world's most widely consumed natural stimulant that triggers the release of dopamine, serotonin, and norepinephrine to raise arousal and reduce fatigue.

Cocaine

A powerful natural stimulant extracted from South American coca plants that blocks dopamine reuptake, producing intense energy and euphoria.

Amphetamines

Laboratory-manufactured stimulant drugs that stimulate the central nervous system by increasing the release of dopamine, norepinephrine, and serotonin.

Methamphetamine

A highly potent, illegal amphetamine drug (crystal meth) that increases dopamine, serotonin, and norepinephrine activity, causing up to eight hours of heightened energy and euphoria.

Depressants

A class of psychoactive drugs that slow down body functions, mental processes, and neural activity, often by enhancing GABA action.

Alcohol

A depressant beverage containing ethyl alcohol that binds to GABA receptors, impairing judgment, inhibition, and motor coordination.

Sedative-Hypnotic Drugs

Central nervous system depressants used in low doses to reduce anxiety and in higher doses to induce sleep, including barbiturates and benzodiazepines.

Barbiturates

Major tranquilizers and addictive sedative-hypnotic drugs that depress central nervous system activity by attaching to GABA receptors and enhancing GABA action.

Benzodiazepines

Minor tranquilizers (such as Valium and Xanax) that reduce anxiety by binding to GABA receptors and enhancing GABA activity without causing extreme drowsiness.

Opioids

Drugs derived from opium (such as morphine, heroin, and codeine) that depress the central nervous system and bind to natural endorphin receptor sites to relieve pain.

Hallucinogens

Psychoactive drugs that distort perception and produce visual or auditory hallucinations by altering serotonin or endocannabinoid pathways.

LSD

A powerful synthetic hallucinogen (acid) that alters perception by binding to serotonin receptor sites in the brain.

Cannabis

Drugs derived from the hemp plant Cannabis sativa (such as marijuana) containing THC that produce a mixture of hallucinogenic, depressant, and stimulant effects.

Tolerance

A state where repeated drug use leads to reduced sensitivity, requiring larger doses to produce the original desired effect.

Addiction

A compulsive, uncontrollable craving for and use of a substance despite severe physical, psychological, or social consequences.

Withdrawal

The cluster of painful physical and psychological symptoms that occur when a person suddenly stops using an addictive drug.

Substance Use Disorder

A diagnostic condition characterized by uncontrollable drug use that severely impairs daily functioning, health, and social relationships.