Psychology

autonomic nervous system

The division of the peripheral nervous system that governs involuntary processes such as heart rate and digestion.

brain

The central organ of the central nervous system that processes information and controls body functions.

central nervous system

The part of the nervous system consisting of the brain and spinal cord that processes information and coordinates responses.

parasympathetic nervous system

The division of the autonomic nervous system responsible for the 'rest and digest' response that helps reduce anxiety and promote relaxation.

peripheral nervous system

The part of the nervous system outside the brain and spinal cord that connects the central nervous system to the rest of the body.

somatic nervous system

The division of the peripheral nervous system that governs voluntary processes and skeletal muscle control.

spinal cord

The bundle of nerves extending from the brain through the vertebral column that is part of the central nervous system.

sympathetic nervous system

The division of the autonomic nervous system responsible for the 'fight or flight' response that contributes to feelings of anxiety.

acetylcholine

A neurotransmitter involved in muscle movement, learning, and memory.

action potential

A rapid change in a neuron's membrane potential that allows it to transmit signals over long distances.

addiction

A compulsive pattern of psychoactive drug use that can create significant withdrawal symptoms when the drug is no longer consumed.

adrenaline

A hormone involved in the stress response, increasing heart rate and arousal.

agonists

Psychoactive drugs that bind to receptors and encourage neural firing by mimicking or enhancing neurotransmitter effects

all-or-nothing principle

The rule that a neuron either fires completely or does not fire at all; there is no partial firing of an action potential.

antagonists

Psychoactive drugs that bind to receptors and discourage neural firing by blocking neurotransmitter effects.

central nervous system

The part of the nervous system consisting of the brain and spinal cord that processes information and coordinates responses.

depolarization

The process by which a neuron's membrane potential becomes less negative, moving toward or past zero, triggering an action potential.

depressants

Psychoactive drugs such as alcohol that typically decrease neural activity and slow down the central nervous system.

dopamine

A neurotransmitter involved in reward, motivation, movement, and mood regulation

endorphins

Neurotransmitters involved in pain relief and the experience of pleasure.

excitatory message

A neurotransmitter signal that makes an action potential more likely by depolarizing the receiving neuron.

GABA

An inhibitory neurotransmitter that reduces neural activity and promotes relaxation.

ghrelin

A hormone that increases appetite and signals hunger to the brain, primarily produced in the stomach.

glial cells

Cells in the nervous system that provide structure, insulation, communication, and waste transport to support neural function.

glutamate

An excitatory neurotransmitter involved in learning and memory.

hallucinogens

Psychoactive drugs such as marijuana that typically cause distortions in perception and/or cognition.

hormone

A chemical messenger released into the bloodstream that affects behavior and mental processes similar to neurotransmitters.

inhibitory message

A neurotransmitter signal that makes an action potential less likely by hyperpolarizing the receiving neuron.

interneurons

Neurons in the central nervous system that connect sensory and motor neurons and process information between them.

leptin

A hormone that decreases appetite and signals satiety (fullness) to the brain, produced by fat cells.

melatonin

A hormone that regulates sleep-wake cycles and circadian rhythms.

motor neurons

Neurons that transmit signals from the central nervous system to muscles to produce movement and behavior.

neural transmission

The process by which neurons communicate through the release and reception of neurotransmitters across synapses.

neurons

Neural cells that transmit information throughout the nervous system and are responsible for behavior and mental processes.

neurotransmitter

A chemical messenger released by neurons that transmits signals across synapses to affect the activity of other neurons or cells.

neurotransmitter function

The process by which neurotransmitters transmit signals between neurons and affect neural communication.

norepinephrine

A neurotransmitter involved in arousal, attention, and the stress response.

opioids

Psychoactive drugs such as heroin that typically act as pain relievers by affecting pain perception.

oxytocin

A hormone involved in social bonding, trust, and reproductive behaviors.

peripheral nervous system

The part of the nervous system outside the brain and spinal cord that connects the central nervous system to the rest of the body.

psychoactive drugs

Substances that alter brain chemistry and affect behavior, mental processes, and consciousness.

reflex arc

A neural pathway in the spinal cord that enables rapid, automatic responses to stimuli without requiring brain involvement.

refractory period

A period of time after an action potential during which a neuron cannot fire again, either absolutely (no new action potential possible) or relatively (only with stronger stimulation).

resting potential

The stable negative electrical charge of a neuron at rest, typically around -70 millivolts.

reuptake

The process by which neurotransmitters are removed from the synaptic cleft and reabsorbed by the presynaptic neuron.

reuptake inhibitors

Psychoactive drugs that block the reabsorption of neurotransmitters back into the presynaptic cell, prolonging their effects.

sensory neurons

Neurons that transmit information from sensory receptors to the central nervous system in response to stimuli.

serotonin

A neurotransmitter involved in mood regulation, sleep, and emotional processing.

stimulants

Psychoactive drugs such as caffeine and cocaine that typically increase neural activity and arousal.

substance P

A neurotransmitter involved in pain perception and transmission.

threshold

The minimum level of depolarization needed to trigger an action potential in a neuron.

tolerance

A state in which repeated use of a psychoactive drug requires increasing doses to achieve the same effect.

withdrawal symptoms

Negative physical and psychological effects that occur when a person stops using a psychoactive drug to which they are addicted.

Amygdala

A brain structure within the limbic system that processes emotions, particularly fear and emotional memory.

aphasia

A language disorder resulting from damage to brain areas responsible for speech production or comprehension.

association areas

Brain regions in the parietal lobes that process and organize sensory and cognitive information.

brain plasticity

The ability of the brain to rewire itself, modify existing connections, or create new connections throughout development to compensate for damage or support learning.

brain stem

The region of the brain that controls basic life functions such as breathing and heart rate.

brain's reward center

The brain region that processes reward and reinforcement, influencing learning, cognition, and emotional responses.

Broca's area

A region in the left hemisphere responsible for speech production.

cerebellum

A brain structure that controls coordination of muscle movement, balance, and procedural learning.

cerebral cortex

The outer layer of the brain divided into two hemispheres, containing the limbic system and lobes that process sensory information and control higher-order functions.

contralateral hemispheric organization

The brain's organization in which each hemisphere processes sensory information from the opposite side of the body.

corpus callosum

A bundle of nerve fibers connecting the left and right hemispheres of the brain, allowing communication between them.

EEG

Electroencephalography; a brain imaging technique that measures electrical activity of the brain.

fMRI

Functional magnetic resonance imaging; a brain imaging technique that measures blood flow to identify active brain regions.

frontal lobes

Brain lobes located just behind the forehead that control linguistic processing, higher-order thinking, and executive functioning, including the motor cortex.

hippocampus

A brain structure within the limbic system that is essential for forming and consolidating memories.

hypothalamus

A brain structure within the limbic system that regulates hormones, temperature, hunger, and other homeostatic functions.

lesioning

A surgical procedure that damages or removes a specific brain area to study its function.

limbic system

A group of brain structures including the thalamus, hypothalamus, pituitary gland, hippocampus, and amygdala that regulate emotion, memory, and motivation.

medulla

A structure within the brain stem that regulates vital functions including breathing and heart rate.

motor cortex

A region located at the rear of the frontal lobes that controls most types of skeletal movement.

occipital lobes

Brain lobes located at the rear of the cerebral cortex that process visual information.

parietal lobes

Brain lobes located near the back crown of the cerebral cortex that contain association areas for processing and organizing information and the somatosensory cortex for touch sensitivity.

pituitary gland

An endocrine gland within the limbic system that releases hormones controlling growth, metabolism, and other bodily functions.

prefrontal cortex

A region of the frontal lobes responsible for executive functioning, decision-making, and higher-order thinking.

reticular activating system

A network of neurons in the brain that controls voluntary movement, eye movement, and influences learning, cognition, and emotion.

somatosensory cortex

A region in the parietal lobes that processes touch sensitivity and tactile information.

split brain research

Research conducted on patients with severed corpus callosums that reveals specialization of the left and right brain hemispheres.

temporal lobes

Brain lobes located on the sides of the cerebral cortex that process auditory and linguistic information.

thalamus

A brain structure that processes most sensory information before it reaches the cerebral cortex; the olfactory system bypasses this structure.

Wernicke's area

A region in the left hemisphere responsible for speech comprehension.