Introduction to the Nervous System Unit

This set of flashcards covers key vocabulary and concepts related to the nervous system and neuron signaling as discussed in the lecture notes.

Electrophysiology

The study of electrical properties of biological cells and tissues, specifically how neurons send electrical signals.

Concentration Gradient

A difference in the concentration of a substance across a space, which influences the movement of ions such as sodium and potassium.

Membrane Potential

The voltage difference across a neuron's membrane, significant for understanding how neurons communicate.

Equilibrium Potential

The membrane potential at which there is no net movement of a particular ion across the membrane.

Depolarization

The process by which the membrane potential becomes less negative or more positive due to the influx of sodium ions.

Hyperpolarization

The process by which the membrane potential becomes more negative than the resting potential due to the efflux of potassium ions.

Local (Graded) Potentials

Small changes in membrane potential that can be depolarizing or hyperpolarizing, and are decremental in nature.

Action Potential

A rapid, all-or-nothing change in membrane potential that propagates along the axon, initiated when a threshold is reached.

Threshold

The membrane potential level (usually around -55 mV) that must be reached to trigger an action potential.

Refractory Period

The period of time following an action potential during which a neuron is unable to fire another action potential.

Absolute Refractory Period

The time during which no new action potential can be initiated regardless of the strength of incoming stimuli.

Relative Refractory Period

The period following an absolute refractory period where an action potential can occur only if the stimulus is very strong.

Ligand-Gated Ion Channel

A type of ion channel that opens in response to the binding of a chemical messenger, such as a neurotransmitter.

Voltage-Gated Ion Channel

A type of ion channel that opens or closes in response to changes in membrane potential.

Inactivation Gate

A component of voltage-gated channels that prevents ion flow after a short period of being open.

Dendrites

Extensions of a neuron that receive signals from other neurons and convey them towards the cell body.

Axon Hillock

The part of a neuron where the axon begins and action potentials are typically initiated.