Neuroscience and Behavior – The Neuron

Vocabulary flashcards covering key terms related to neuron structure, action potentials, ion dynamics, neurotransmission, and major neurotransmitters.

Neuron

Primary cell of the nervous system that processes and transmits information.

Sensory Neuron

Neuron that receives information from the external world and conveys it to the brain via the spinal cord.

Motor Neuron

Neuron that carries signals from the spinal cord to muscles to produce movement.

Interneuron

Neuron that connects sensory neurons, motor neurons, or other interneurons within the nervous system.

Dendrite

Branch-like extension of a neuron that receives information from other neurons and relays it to the cell body.

Cell Body (Soma)

Part of the neuron that coordinates information-processing tasks and keeps the cell alive.

Axon Hillock

Cone-shaped region between the cell body and axon where action potentials are initiated.

Axon

Long fiber that transmits electrical signals to other neurons, muscles, or glands.

Myelin Sheath

Insulating layer of fatty material that covers some axons and speeds neural conduction.

Node of Ranvier

Gap between segments of myelin where the axonal membrane is exposed and ion exchange occurs.

Axon Collateral

Branch of an axon that allows a neuron to communicate with multiple targets.

Terminal Buttons

Knoblike structures at an axon’s end that release neurotransmitters into the synapse.

Synapse

Junction between the terminal button of one neuron and the dendrite or cell body of another.

Conduction

Movement of an electrical signal within a neuron.

Transmission

Movement of a chemical signal between neurons across the synapse.

Action Potential

All-or-none electrical impulse that travels down the axon, caused by rapid ion exchange.

Resting Potential

-70 mV charge inside a neuron when inactive, maintained by ion distributions.

Threshold of Excitation

Membrane voltage (~-55 mV) that must be reached to trigger an action potential.

Depolarization

Phase of the action potential when Na⁺ rushes in, making the cell interior more positive.

Repolarization

Return to negative membrane potential as K⁺ leaves the neuron after depolarization.

Hyperpolarization

Membrane potential becomes more negative than resting level following an action potential.

Saltatory Conduction

Jumping of the action potential from one Node of Ranvier to the next along myelinated axons.

Voltage-Gated Channel

Ion channel that opens or closes in response to changes in membrane potential.

Ligand-Gated Channel

Ion channel that opens when a neurotransmitter binds to its receptor.

Na⁺/K⁺ Pump

Active transporter moving 3 Na⁺ out and 2 K⁺ into the cell to restore ion balance.

EPSP (Excitatory Postsynaptic Potential)

Small depolarization of a postsynaptic neuron that increases the chance of firing.

IPSP (Inhibitory Postsynaptic Potential)

Small hyperpolarization of a postsynaptic neuron that decreases the chance of firing.

Neurotransmitter

Chemical messenger released by neurons to transmit signals across a synapse.

Vesicle

Membrane-bound sac in terminal buttons that stores neurotransmitters for release.

Receptor

Protein on the postsynaptic membrane that binds neurotransmitters and initiates a response.

Reuptake

Process in which neurotransmitters are reabsorbed into the presynaptic neuron for reuse.

Enzyme Deactivation

Breakdown of neurotransmitters in the synapse by specialized enzymes.

Autoreceptor

Presynaptic receptor that detects released neurotransmitter and regulates further release.

Selective Serotonin Reuptake Inhibitor (SSRI)

Drug that increases serotonin levels by blocking its reuptake; used to treat depression.

Serotonin (5-HT)

Neurotransmitter involved in mood, sleep, appetite, and aggressive behavior.

Dopamine (DA)

Neurotransmitter that regulates movement, motivation, pleasure, and emotional arousal.

Acetylcholine (ACh)

Neurotransmitter crucial for voluntary motor control and memory.

Glutamate

Major excitatory neurotransmitter involved in information transmission throughout the brain.

GABA (Gamma-Aminobutyric Acid)

Primary inhibitory neurotransmitter in the brain.

Norepinephrine (NE)

Neurotransmitter associated with vigilance and heightened awareness of danger.

Endorphins

Neurochemicals that act within pain pathways and emotion centers to produce analgesia and euphoria.

Psychopharmacology

Study of how drugs affect the brain and behavior.