Neuron Communication (2113 Exam 1)

Na⁺ (Inside Neuron / Outside Neuron)

Low / High

K⁺ (Inside Neuron / Outside Neuron)

High / Low

Cl⁻ (Inside Neuron / Outside Neuron)

Low / High

Ca²⁺ (Inside Neuron / Outside Neuron)

Very Very Low / Higher

Ion

Charged Atom

Cation

Positively Charged Atom

Anion

Negatively Charged Atom

Membrane Potential

The electrical charge across the cell membrane (measured by a difference of electrical charge inside and outside of the cell)

Resting Potential

The stable, negative electrical charge difference across a neuron's membrane when it is not actively sending a signal

Diffusion

When ions move from places of high concentration to low concentration

Electrostatic Pressure

Either attractive or repulsive force between charged ions (opposites attract / like charges repel)

Voltage-Gated Ion Channels

Opens in response to a certain voltage reached in the membrane (membrane potential)

Ligand-Gated Ion Channels

Open in response to a specific extracellular neurotransmitters

Action Potential

A rapid, temporary reversal of the electric charge across a cell membrane (typically in neurons or muscle cells) that acts as a signal to transmit information

Depolarization

Rapidly changes a membranes potential from a negative charge to a positive charge

Repolarization

The phase of an action potential where the membrane potential returns to a negative

Hyperpolarization

The final phase where the neuron's membrane potential becomes more negative (typically below -70mV) than its resting potential

Saltatory Conduction

The rapid, "jumping" propagation of action potentials along myelinated axons, where the signal leaps between uninsulated gaps called nodes of Ranvier

Electrical Synapse

Allow for nearly instantaneous, bidirectional communication via direct ion flow through gap junctions, often used for synchronization

Chemical Synapse

Slower, unidirectional, and use neurotransmitters to bridge a larger synaptic cleft, allowing for signal amplification, flexibility, and modulation

Ligands

Anything that can bind to a receptor (Neurotransmitters)

Ionotropic Receptor

Ligand-gated ion channels that produce fast, direct, and short-lived postsynaptic potentials in milliseconds

Metabotropic Receptor

G-protein-coupled receptors (GPCRs) that initiate slower, long-lasting, and indirect intracellular signaling cascades

Excitatory Effect of Neurotransmitters

Stimulate the receiving neuron, making it more likely to fire an action potential

Inhibitory Effect of Neurotransmitters

Calm the receiving neuron, making it less likely to fire an action potential

Agonist

Activate receptors to produce a biological response, acting as a trigger to initiate actions like neurotransmitter release

Antagonist

Block receptors, inhibiting or dampening the biological response by preventing agonists from binding

Glutamate

The main excitatory neurotransmitter in the brain / Involved in EPSPs & NMDA and AMPA receptors involved in memory

GABA

The main inhibitory neurotransmitter in the brain / Involved in IPSPs

Acetycholine

Involved in movement

Dopamine

Involved in movement, attention, learning & drug use

Major CNS Dopaminergic Systems

Nigrostriatal System, Mesolimbic System, Mesocortical System

Norepinephrine / Noradrenaline & Epinephrine / Adrenaline

Involved in Behavioral Excitation

Serotonin / 5-HT

Involved in the regulation of mood, eating, sleeping, arousal, & pain

Histamine

Involved in wakefulness