AP PSYCH UNIT 1 VOCAB

Neuron

A cell that transmits messages throughout the nervous system.

Dendrites

Branch-like parts of a neuron that receive messages from other neurons.

Axon

Long extension of a neuron that sends messages away from the cell body.

Myelin Sheath

Fatty covering that speeds up the transmission of neural impulses.

Action Potential

A brief electrical charge that travels down an axon.

Resting Potential

The state of a neuron when not firing a neural impulse.

Refractory Period

Short time after an action potential during which the neuron cannot fire again.

Synapse

The gap between neurons where neurotransmitters are released.

Neurotransmitters

Chemical messengers that cross the synaptic gap.

Acetylcholine (ACh)

Neurotransmitter for movement and memory; low levels linked to Alzheimer's.

Dopamine

Neurotransmitter involved in pleasure, emotion, movement; too much = schizophrenia, too little = Parkinson's.

Serotonin

Neurotransmitter for mood, sleep, appetite; low levels linked to depression.

Norepinephrine

Arousal and alertness neurotransmitter.

GABA

Inhibitory neurotransmitter; low levels = anxiety, seizures.

Glutamate

Excitatory neurotransmitter involved in memory; too much = migraines or seizures.

Endorphins

Natural painkillers produced by the brain.

Central Nervous System (CNS)

Brain and spinal cord.

Peripheral Nervous System (PNS)

All nerves outside the brain and spinal cord.

Somatic Nervous System

Controls voluntary movements of skeletal muscles.

Autonomic Nervous System

Controls involuntary body functions like heartbeat and digestion.

Sympathetic Nervous System

Activates fight-or-flight response.

Parasympathetic Nervous System

Calms the body down after arousal.

Endocrine System

Body's slow chemical communication system using hormones.

Hormones

Chemical messengers secreted by glands into the bloodstream.

Pituitary Gland

The master gland that controls other endocrine glands.

Adrenal Glands

Secrete adrenaline; help with stress response.

Thyroid Gland

Regulates metabolism.

Pineal Gland

Releases melatonin; involved in sleep-wake cycles.

Pancreas

Regulates blood sugar with insulin.

Brainstem

Oldest part of the brain; controls basic survival functions.

Medulla

Controls heartbeat and breathing.

Pons

Helps coordinate movement and sleep.

Reticular Formation

Controls arousal and consciousness.

Thalamus

Brain's sensory switchboard.

Cerebellum

Coordinates voluntary movement and balance.

Limbic System

Group of brain structures involved in emotions, memory, and drives.

Amygdala

Processes emotions like fear and aggression.

Hippocampus

Helps form new memories.

Hypothalamus

Maintains body's homeostasis and controls the pituitary gland.

Cerebral Cortex

Outer layer of the brain; responsible for complex thinking.

Frontal Lobes

Responsible for planning, judgment, and motor functions.

Motor Cortex

Controls voluntary movements.

Broca's Area

Controls speech production.

Parietal Lobes

Processes sensory input for touch and body position.

Somatosensory Cortex

Processes touch and body sensation.

Temporal Lobes

Processes hearing and language.

Wernicke's Area

Language comprehension.

Occipital Lobes

Processes visual information.

EEG

Measures brain's electrical activity.

CT Scan

Uses X-rays to create images of the brain.

PET Scan

Shows brain activity using radioactive glucose.

MRI

Shows detailed brain structures.

fMRI

Measures brain activity and structure.

Consciousness

Awareness of ourselves and our environment.

Circadian Rhythm

24-hour biological clock.

Sleep

A natural loss of consciousness, critical for health and memory.

Sleep Cycle

90-minute repeating patterns of NREM and REM sleep.

NREM-1

Light sleep; may experience hallucinations.

NREM-2

Sleep spindles appear; deeper sleep.

NREM-3

Deep sleep; slow delta waves.

REM Sleep

Dream sleep; rapid brain activity and muscle paralysis.

Delta Waves

Large, slow brain waves during deep sleep.

Alpha Waves

Slow brain waves of a relaxed, awake state.

Sleep Deprivation

Lack of sleep leading to cognitive and health problems.

Insomnia

Inability to fall or stay asleep.

Narcolepsy

Sudden, uncontrollable sleep attacks.

Sleep Apnea

Stops breathing during sleep.

Night Terrors

Intense fear during deep NREM sleep.

Dreams

Sequences of images, emotions, and thoughts during REM sleep.

REM Rebound

More REM sleep after REM deprivation.

Sensation

Receiving raw sensory input from the environment.

Perception

Organizing and interpreting sensory information.

Sensory Neurons

Carry messages from sensory organs to the brain.

Absolute Threshold

Minimum stimulus needed to detect something 50% of the time.

Difference Threshold

Smallest detectable difference between two stimuli.

Weber's Law

Difference threshold is a constant proportion, not amount.

Sensory Adaptation

Reduced sensitivity after constant stimulation.

Transduction

Converting sensory input into neural impulses.

Signal Detection Theory

Predicts how and when we detect faint stimuli amid background noise.

Selective Attention

Focusing on one stimulus at a time.

Inattentional Blindness

Failure to see visible objects when attention is elsewhere.

Change Blindness

Failure to notice changes in the environment.

DNA

Molecule that holds genetic information.

Genes

Segments of DNA that code for traits.

Genome

Complete set of genetic information.

Identical Twins

Develop from the same fertilized egg; genetically identical.

Fraternal Twins

Develop from separate eggs; like regular siblings.

Heritability

Proportion of variation due to genes.

Epigenetics

Study of how environment can trigger or block gene expression.