AP Psychology Unit 1 Vocab: Biological Bases of Behavior

Unit 1 focuses on how the functions of our biological systems influence our physical and mental actions and responses. Knowledge of biological functions and mechanisms, especially how neurons communicate, how the brain functions, and how sleep and sensation impact behavior and mental processes, will help students gain a more comprehensive understanding of psychology throughout the course as well as awareness of how all behaviors and mental processes are based in biological operations. For instance, in Unit 2, students will learn that biological mechanisms are vital to memory, and in Unit 5, they will discover that damage to certain biological structures can be the cause of psychological disorders.

Nervous System

The body's speedy, electrochemical communication network consisting of all nerve cells.

Central Nervous System

The brain and spinal cord; the body's main decision-making center.

Nerves

Bundled axons that form neural cables connecting the central nervous system with muscles and glands.

Reflex

A simple, automatic response to a sensory stimulus, governed by the spinal cord.

Autonomic Nervous System

Controls involuntary biological functions like heartbeat, digestion, and glandular activity.

Sympathetic Nervous System

Subdivision of autonomic system that arousal and mobilizes energy ("fight or flight").

Peripheral Nervous System

Sensory and motor neurons connecting the central nervous system to the rest of the body.

Somatic Nervous System

Subdivision of peripheral system controlling voluntary movements of skeletal muscles.

Parasympathetic Nervous System

Subdivision of autonomic system that calms the body and conserves energy ("rest and digest").

Neurons

Individual nerve cells; the basic building blocks of the nervous system.

Cell Body

The neuron's core structure that contains the nucleus and keeps the cell alive.

Dendrites

Branching extensions of a neuron that receive messages and conduct impulses toward the cell body.

Axon

The long neuron extension that passes messages through its branches to other neurons or muscles.

Myelin

A fatty layer segmentally encasing the axon to speed up transmission of neural impulses.

Synapse

The junction/gap between the axon tip of the sending neuron and the dendrite of the receiving neuron.

Glial Cells

Cells in the nervous system that support, nourish, protect neurons, and play a role in learning.

Reflex Arc

The neural pathway that controls a reflex action (sensory neuron to interneuron to motor neuron).

Sensory Neurons

Neurons that carry incoming information from sensory receptors to the central nervous system.

Motor Neurons

Neurons that carry outgoing information from the central nervous system to muscles and glands.

Interneurons

Neurons within the brain and spinal cord that communicate internally between sensory and motor inputs.

Action Potential

A brief electrical charge that travels down an axon when a neuron fires.

All-or-Nothing Principle

A neuron's reaction of either firing at full strength or not firing at all.

Depolarization

The loss of inside/outside electrical charge difference, causing the neuron to fire.

Reuptake

A neurotransmitter's reabsorption by the sending neuron after firing across a synapse.

Multiple Sclerosis

A disease where the myelin sheath degrades, causing loss of muscle control and communication.

Neurotransmitters

Chemical messengers that cross the synaptic gap between neurons to carry signals.

Excitatory Neurotransmitters

Chemicals that increase the likelihood that a receiving neuron will fire an action potential.

Dopamine

Neurotransmitter influencing movement, learning, attention, and emotion; linked to pleasure/reward.

Norepinephrine

Neurotransmitter that helps control alertness and arousal; involved in stress responses.

GABA

The primary inhibitory neurotransmitter that calms central nervous system activity.

Substance P

A neurotransmitter involved in the transmission of pain signals to the brain.

Hormones

Chemical messengers manufactured by endocrine glands that travel through the bloodstream.

Leptin

A hormone produced by fat cells that signals the brain to suppress appetite.

Melatonin

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

Refractory Period

A brief resting pause after a neuron fires, during which another action potential cannot occur.

Resting Potential

The stable, negative electrical charge of a neuron when it is inactive (-70mV).

Threshold

The level of stimulation required to trigger a neural impulse (-55mV).

Myasthenia Gravis

A chronic autoimmune disorder where antibodies destroy communication between nerves and muscles.

Inhibitory Neurotransmitters

Chemicals that decrease the likelihood that a receiving neuron will fire an action potential.

Serotonin

Neurotransmitter that affects mood, hunger, sleep, and arousal; low levels linked to depression.

Glutamate

Major excitatory neurotransmitter involved in memory; excess can cause migraines or seizures.

Endorphins

Natural, opiate-like neurotransmitters linked to pain control and pleasure ("runner's high").

Acetylcholine

Neurotransmitter enabling muscle action, learning, and memory; deteriorates with Alzheimer's.

Endocrine System

The body's "slow" chemical communication system; glands that secrete hormones into blood.

Adrenaline

Hormone released in response to stress/danger that increases heart rate, blood pressure, and energy.

Ghrelin

A hormone produced by the stomach that signals hunger to the brain.

Oxytocin

Hormone enabling social bonding, trust, empathy, and physical touch/labor contractions.

Psychoactive Drugs

Chemical substances that alter perceptions, mood, consciousness, and behavior.

Substance Use Disorder

Continued substance craving and use despite significant life disruption or physical risk.

Antagonist

A molecule that blocks or inhibits a neurotransmitter's action at a receptor site.

Stimulants

Drugs that excite neural activity and speed up body functions (caffeine, nicotine, cocaine).

Caffeine

A widely used central nervous system stimulant that temporarily wards off drowsiness.

Cocaine

A powerful, addictive stimulant derived from the coca plant; produces temporarily increased alertness and euphoria.

Methamphetamines

A powerfully addictive stimulant that speeds up body functions and depletes dopamine over time.

Ecstasy

A synthetic stimulant and mild hallucinogen that produces euphoria and social intimacy.

Opioids

Opium and its derivatives; depress neural activity, temporarily lessening pain and anxiety.

Heroine

A highly addictive opioid drug synthesized from morphine that causes intense euphoria.

Addiction

Compulsive craving of drugs or behaviors despite known adverse consequences.

Agonist

A molecule that binds to a receptor site and mimics a neurotransmitter's effects.

Reuptake Inhibitor

A substance that blocks the reabsorption of neurotransmitters, increasing their levels in the synapse.

Depressants

Drugs that reduce neural activity and slow body functions (alcohol, barbiturates, opiates).

Barbiturates

Depressant drugs that depress central nervous system activity, reducing anxiety but impairing memory.

Alcohol

A depressant drug that slows brain activity, impairs judgment, and lowers inhibitions.

Hallucinogens

Psychedelic drugs that distort perceptions and evoke sensory images in the absence of sensory input.

Near-Death Experience

An altered state of consciousness reported after a close brush with death, often similar to hallucinations.

Marijuana

A plant whose leaves contain THC, triggering mild hallucinations, relaxation, and sensory distortion.

LSD

A powerful hallucinogenic drug, also known as acid, that creates vivid sensory trips.

Dependence

A condition in which physical or psychological symptoms occur when a drug is discontinued.

Tolerance

The diminishing effect with regular use of the same dose of a drug, requiring larger doses for effect.

Withdrawal

The discomfort and distress that follow discontinuing an addictive drug or behavior.

Biological Psychology

Study of the links between biological process (genetic, neural, hormonal) and psychological processes.

Biopsychosocial Approach

Integrates biological, psychological, and social-cultural factors to understand human behavior.

Levels of Analysis

The differing complementary views (biological to social) for analyzing any given phenomenon.

Brain Plasticity (neuroplasticity)

The brain's ability to change and adapt by forming new neural connections after damage or experience.

EEG

Recording of electrical wave sweeps across the brain's surface via scalp electrodes.

MEG

Brain imaging technique that measures magnetic fields produced by the brain's electrical activity.

MRI

Technique using magnetic fields and radio waves to produce computer-generated images of soft tissue/brain anatomy.

CT

A series of X-ray photographs taken from different angles and combined by computer into a composite scan.

PET

A visual display of brain activity that detects where a radioactive form of glucose goes while a task is done.

fMRI

Technique revealing blood flow and brain activity by comparing successive MRI scans to show function.

Lesions

Tissue destruction; a brain lesion is a naturally or experimentally caused destruction of brain tissue.

Brain Stem

The oldest part and central core of the brain, responsible for automatic survival functions.

Hindbrain

Lower part of the brain including the medulla, pons, and cerebellum; controls basic survival functions.

Midbrain

Small central part of the brainstem that integrates sensory information and relays it upward.

Forebrain

The largest and most complex brain region; controls complex cognitive activities, sensory and associative functions.

Medulla Oblongata

The base of the brainstem; controls heartbeat and breathing.

Reticular Activating System (Reticular Formation)

A nerve network in the brainstem that plays an important role in controlling arousal and alertness.

Cerebellum

The "little brain" at the rear of the brainstem; processes sensory input and coordinates movement and balance.

Cerebral Cortex

The intricate fabric of interconnected neural cells covering the cerebral hemispheres; ultimate control center.

Reward Center

Brain structures (like the nucleus accumbens) that mediate feelings of pleasure and reinforcement.

Limbic System

Neural system located below the cerebral hemispheres; associated with emotions and drives.

Hypothalamus

Structure below the thalamus; directs eating, drinking, body temperature, and governs the endocrine system.

Pituitary Gland

The endocrine system's most influential gland; under hypothalamus control, regulates growth and other glands.

Hippocampus

A neural center located in the limbic system; helps process explicit memories for storage.

Amygdala

Two lima-bean-sized neural clusters in the limbic system; linked to emotion, especially fear and aggression.

Corpus Callosum

The large band of neural fibers connecting the two brain hemispheres and carrying messages between them.

Split Brain patients

Individuals whose corpus callosum has been surgically severed, isolating the two hemispheres.

Broca’s Area

Area in the left frontal lobe that controls language expression and muscle movements involved in speech.

Wernicke’s Area

Area in the left temporal lobe involved in language comprehension and expression.

Hemispheres

The left and right halves of the cerebral cortex, each controlling opposite sides of the body.