ahhhhhhh

Neuroscience

The scientific study of how the body’s electrochemical communication system functions and coordinates behavior.

Central Nervous System (CNS)

The brain and spinal cord; processes information and directs responses.

Peripheral Nervous System (PNS)

All nerves outside the CNS that carry sensory information to the brain and motor commands to the body.

Somatic Nervous System

The branch of the PNS that controls voluntary movement and transmits sensory signals to the CNS.

Autonomic Nervous System

The branch of the PNS that regulates involuntary body functions like heart rate and digestion.

Sympathetic Nervous System

Division of the autonomic system that prepares the body for action by increasing heart rate, breathing, and energy use.

Parasympathetic Nervous System

Division of the autonomic system that calms the body and promotes recovery after arousal.

Neuron

A nerve cell that receives, processes, and sends information using electrical and chemical signals.

Glial Cells

Supportive brain cells that provide nutrients, remove waste, and help repair neural damage.

Dendrites

Branching neuron structures that receive messages from neighboring neurons.

Axon

Long fiber of a neuron that carries electrical impulses away from the cell body toward other cells.

Terminal Buttons

Small end structures of an axon that release neurotransmitters into a synapse.

Resting Potential

The stable negative charge of an inactive neuron caused by an imbalance of ions across the membrane.

Threshold

The minimum level of stimulation required to trigger an action potential in a neuron.

Action Potential

A brief electrical charge that travels down an axon and transmits information without losing intensity.

All-or-None Principle

The rule that a neuron either fires completely once threshold is reached or does not fire at all.

Synapse

The tiny gap between neurons where chemical communication occurs.

Neurotransmitters

Chemical messengers that carry signals across a synapse from one neuron to another.

Acetylcholine

A neurotransmitter involved in muscle movement, learning, and memory; low levels are linked to Alzheimer’s disease.

GABA

The brain’s main inhibitory neurotransmitter that reduces neural firing and helps control anxiety.

Glutamate

The brain’s main excitatory neurotransmitter that strengthens synaptic connections important for learning and memory.

Norepinephrine

A neurotransmitter that increases alertness and arousal; high levels are linked to mania and low levels to depression.

Dopamine

A neurotransmitter that regulates voluntary movement, reward anticipation, and attention; low levels cause Parkinson’s disease.

Serotonin

A neurotransmitter that affects mood, sleep, and appetite; low levels are associated with depression.

Endorphins

Natural chemicals that reduce pain and create feelings of pleasure or euphoria.

Oxytocin

A hormone and neurotransmitter involved in bonding, social connection, and the “tend and befriend” stress response.

Neural Network

A connected group of neurons that processes and integrates sensory input with motor output.

Hindbrain

The lowest brain region controlling survival functions such as breathing and heart rate.

Medulla

A hindbrain structure that regulates vital functions like heartbeat and breathing.

Pons

A hindbrain structure that helps control sleep, arousal, and facial movements.

Cerebellum

A hindbrain structure that coordinates balance, posture, and fine motor movements.

Midbrain

The region that helps control movement, arousal, and dopamine production.

Substantia Nigra

A midbrain structure that produces dopamine and supports smooth voluntary movement.

Reticular Formation

A network of neurons in the brainstem that maintains alertness and regulates sleep–wake cycles.

Forebrain

The highest brain region responsible for complex thought, planning, and emotion.

Limbic System

A forebrain structure involved in emotion and memory formation.

Amygdala

Part of the limbic system that processes fear, aggression, and emotional learning.

Hippocampus

Part of the limbic system that forms and retrieves long-term memories.

Thalamus

A sensory relay station that sends incoming signals to the appropriate cortical areas.

Basal Ganglia

Forebrain structures that coordinate and smooth voluntary muscle movements.

Hypothalamus

A small forebrain structure that regulates hunger, thirst, body temperature, stress, and sexual behavior.

Cerebral Cortex

The outer layer of the forebrain responsible for higher cognitive processes such as reasoning and planning.

Frontal Lobe

Cortex region involved in decision making, personality, and voluntary muscle movements.

Prefrontal Cortex

Front part of the frontal lobe responsible for planning, reasoning, and self-control.

Parietal Lobe

Cortex region that processes spatial information and sensations of touch.

Temporal Lobe

Cortex region that processes hearing, language, and memory.

Occipital Lobe

Cortex region that processes visual information.

Somatosensory Cortex

Area of the parietal lobe that receives information about body sensations.

Motor Cortex

Area of the frontal lobe that controls voluntary muscle movements.

Association Cortex

Cortical areas that integrate sensory and motor information and support higher thinking.

Corpus Callosum

The large band of axons connecting the two cerebral hemispheres for communication.

Left Hemisphere

The side of the brain specialized for language, speech, and analytical processing.

Right Hemisphere

The side of the brain specialized for spatial abilities, facial recognition, and emotional processing.

Endocrine System

A network of glands that regulates the body by secreting hormones into the bloodstream.

Hormones

Chemical messengers secreted by glands that influence growth, metabolism, and mood.

Brain Plasticity

The brain’s ability to reorganize and form new connections after injury or experience.

Collateral Sprouting

The growth of new axon branches from healthy neurons to replace connections lost by damaged neurons.

Substitution of Function

The process in which an undamaged brain region takes over the functions of a damaged area.

Neurogenesis

The formation of new neurons, especially in the hippocampus.

Brain Graft

The implantation of healthy tissue into a damaged area of the brain to restore function.

Chromosomes

Threadlike structures in cell nuclei that contain DNA; humans normally have 46.

Genotype

An individual’s complete genetic makeup or blueprint.

Phenotype

The observable physical and psychological traits resulting from the interaction of genotype and environment.

Dominant Gene

A gene that is expressed in the phenotype even when only one copy is present.

Recessive Gene

A gene expressed in the phenotype only when both copies are recessive.

Polygenic Inheritance

The influence of multiple genes on a single characteristic such as height or intelligence.

Stressors

Events or conditions that challenge or threaten a person’s coping abilities.

Stress

The body’s physical and psychological response to stressors.

Fight or Flight Response

A rapid stress reaction that mobilizes the sympathetic nervous system for survival.

Tend and Befriend Response

A stress reaction promoting social bonding and caregiving, influenced by oxytocin release.