Unit 1 AP Psych

Central Nervous System (CNS)

Brain and spinal cord; processes information and directs responses.

Peripheral Nervous System (PNS)

All nerves outside the CNS that connect it to the rest of the body.

Autonomic Nervous System (ANS)

Part of the PNS controlling involuntary bodily functions (e.g., heartbeat, digestion).

Sympathetic Nervous System

Division of the ANS that arouses the body in stressful situations (“fight or flight”).

Parasympathetic Nervous System

Division of the ANS that calms the body after stress.

Somatic Nervous System

Part of the PNS controlling voluntary movements and transmitting sensory information.

Neuron

Nerve cell that transmits information via electrical and chemical signals.

Sensory Neurons

Neurons that carry information from sensory receptors to the CNS.

Motor Neurons

Neurons that carry instructions from the CNS to muscles or glands.

Interneurons

Neurons within the CNS that process information between sensory and motor neurons.

All-or-Nothing Principle

Neuron fires fully or not at all when threshold is reached.

Resting Potential

The electrical charge of a neuron at rest, before firing.

Depolarization

Change in a neuron’s membrane potential that allows an action potential to occur.

Refractory Period

Time after a neuron fires when it cannot fire again.

Threshold

Minimum level of stimulation required for a neuron to fire.

Multiple Sclerosis (MS)

Disease where myelin sheath is damaged, slowing neural transmission.

Glial Cells

Cells that support and nourish neurons and remove waste.

Myasthenia Gravis

Disorder in which acetylcholine receptors are blocked, causing muscle weakness.

Reuptake

Process where neurotransmitters are reabsorbed by the sending neuron.

Inhibitory Neurotransmitter

Chemical that decreases the likelihood a neuron will fire.

Excitatory Neurotransmitter

Chemical that increases the likelihood a neuron will fire.

Dopamine

Neurotransmitter involved in movement, motivation, and reward.

Norepinephrine

Neurotransmitter involved in arousal, alertness, and stress response.

Serotonin

Neurotransmitter involved in mood, sleep, and appetite.

GABA

Major inhibitory neurotransmitter; reduces neuronal activity.

Glutamate

Major excitatory neurotransmitter; involved in learning and memory.

Acetylcholine (ACh)

Neurotransmitter involved in muscle movement and memory.

Substance P

Neurotransmitter involved in pain perception.

Endorphins

Neurotransmitters that reduce pain and promote pleasure.

Reflex Arc

Neural pathway that controls reflex actions automatically.

Hormones

Chemical messengers released by glands into the bloodstream to regulate processes.

Adrenaline (Epinephrine)

Hormone that increases heart rate and energy in response to stress.

Leptin

Hormone that signals fullness and suppresses appetite.

Ghrelin

Hormone that stimulates hunger.

Melatonin

Hormone regulating sleep-wake cycles.

Oxytocin

Hormone involved in bonding, social attachment, and reproduction.

Agonist Drugs

Drugs that enhance the effects of a neurotransmitter.

Antagonist Drugs

Drugs that block or reduce the effects of a neurotransmitter.

Brain Stem

Base of the brain controlling basic life functions (breathing, heartbeat).

Medulla

Brain stem structure controlling heartbeat and breathing.

Reticular Activating System (RAS)

Brainstem network controlling arousal and attention.

Cerebellum

Brain region that coordinates voluntary movement and balance.

Hypothalamus

Brain structure regulating drives (hunger, thirst) and homeostasis.

Hippocampus

Brain structure critical for forming new memories.

Limbic System

Brain system involved in emotions, memory, and motivation.

Amygdala

Part of the limbic system involved in fear and emotional processing.

Cerebral Cortex

Outer layer of the cerebrum responsible for thinking, perception, and planning.

Thalamus

Brain structure that relays sensory information to the cerebral cortex.

Pituitary Gland

“Master gland” that regulates hormones in the endocrine system.

Corpus Callosum

Bundle of nerve fibers connecting the two hemispheres of the brain.

Somatosensory Cortex

Brain region processing touch and body sensations.

Motor Cortex

Brain region controlling voluntary movements.

Broca’s Area

Brain region controlling speech production.

Wernicke’s Area

Brain region responsible for language comprehension.

Aphasia

Impairment of language due to brain damage.

Split Brain Research

Study of patients whose corpus callosum has been severed.

Brain Plasticity

The brain’s ability to change and adapt in response to experience.

Circadian Rhythm

Biological clock regulating sleep-wake cycles over ~24 hours.

Disruptions to Circadian Rhythm

Circadian misalignment due to jet lag or shift work.

NREM Stage 1

Light sleep; theta waves; drifting in/out of consciousness.

NREM Stage 2

Deeper sleep; sleep spindles and K-complexes appear.

NREM Stage 3

Slow-wave sleep; delta waves; body repairs tissues.

Hypnogogic Sensations

Hallucination-like experiences while falling asleep.

REM Rebound

Increased REM sleep following deprivation.

Insomnia

Difficulty falling or staying asleep.

Sleep Apnea

Disorder where breathing repeatedly stops during sleep.

Narcolepsy

Disorder causing sudden sleep attacks.

Somnambulism

Sleepwalking during NREM sleep.

REM Sleep Behavior Disorder

Acting out dreams due to lack of muscle paralysis in REM.

Left Hemisphere

Controls language, logic, and analytical thinking; processes information from the right side of the body.

Right Hemisphere

Controls spatial abilities, facial recognition, music, and creativity; processes information from the left side of the body.

Parietal Lobe

Brain region that processes sensory information such as touch, pressure, temperature, and spatial awareness.

Occipital Lobe

Brain region responsible for visual processing.

Temporal Lobe

Brain region involved in hearing, language comprehension, and memory.