Action Potentials and Membrane Potential

These flashcards cover key vocabulary and concepts related to action potentials, membrane potentials, and neuronal signaling as outlined in the lecture.

Action Potential

A rapid and temporary change in a membrane potential, typically involving depolarization followed by repolarization.

Depolarization

The process of reducing the negative charge inside a cell, typically by allowing sodium ions (Na+) to flow in.

Repolarization

The process of returning the membrane potential to its resting state after depolarization, usually involving potassium ions (K+) flowing out.

Hyperpolarization

An increase in the negative charge inside a cell, occurring after repolarization as too much potassium exits.

Membrane Potential

The voltage difference across a cell's membrane, typically resting around -70 millivolts.

Sodium-Potassium Pump

An active transport mechanism that moves sodium ions out of the cell and potassium ions into the cell using ATP.

Threshold Potential

The membrane potential that must be reached to trigger an action potential, typically around -55 millivolts.

Voltage-Gated Ion Channels

Proteins in the cell membrane that open in response to changes in voltage, allowing ions to flow in or out.

Graded Potential

Small, variable changes in membrane potential that can lead to action potentials if strong enough.

Ligand-Gated Ion Channels

Ion channels that open in response to the binding of a chemical signal (ligand) to a receptor.

Postsynaptic Potential (PSP)

A graded potential occurring in the dendrites of a neuron after receiving signals at a synapse.

Cotransporter

A protein that facilitates the movement of ions across a membrane by coupling their movement with another substance.

Continuous Conduction

A process where action potentials propagate along an unmyelinated axon by opening sodium channels sequentially.

Saltatory Conduction

The rapid propagation of action potentials along myelinated axons where the action potential jumps between nodes of Ranvier.

Refractory Period

A phase after an action potential during which a neuron cannot fire another action potential.

Acetylcholine

A neurotransmitter involved in muscle contraction by opening ligand-gated ion channels.

Mechanical Deformation

Physical changes in the cell membrane that can open mechanically gated channels.

Diffusion

The movement of ions from an area of high concentration to an area of low concentration.

Generator Potential

A graded potential in unipolar sensory neurons that has the potential to lead to an action potential.

Receptor Potential

A graded potential in sensory cells that leads to the release of neurotransmitters.

Temporal Summation

The process where multiple graded potentials add together over a short time to reach threshold.

Spatial Summation

The process where graded potentials from different locations on the neuron combine to reach threshold.