Neuroscience Lecture Notes on Membrane Potential and Action Potentials

This set of flashcards covers key terms and concepts related to resting membrane potential, action potentials, ion channels, and neurotransmission as discussed in the lecture.

Resting Membrane Potential

The electrical potential of a neuron when it is not actively transmitting signals, typically negative inside due to K⁺ leak channels and Na⁺/K⁺ pump.

Na⁺/K⁺ Pump

A membrane protein that pumps 3 Na⁺ ions out of the neuron and 2 K⁺ ions into the neuron, requiring ATP for energy.

Ligand-Gated Channels

Ion channels that open in response to the binding of a chemical messenger, such as a neurotransmitter.

Voltage-Gated Channels

Ion channels that open in response to changes in membrane potential.

Action Potential

A rapid, temporary change in the membrane potential of a neuron, characterized by depolarization followed by repolarization.

Threshold

The membrane potential that must be reached for an action potential to be generated, leading to the opening of voltage-gated Na⁺ channels.

Depolarization

The phase of an action potential where Na⁺ ions flow INTO the cell, making the inside more positive.

Repolarization

The phase of an action potential where K⁺ ions flow OUT of the cell, restoring the negative internal charge.

Hyperpolarization

A state where the membrane potential becomes more negative than resting potential, often due to prolonged opening of K⁺ channels.

Saltatory Conduction

The process by which action potentials jump between nodes of Ranvier in myelinated axons, speeding up signal conduction.

TTX (Tetrodotoxin)

A neurotoxin that blocks Na⁺ channels, preventing action potentials and causing paralysis.

TEA (Tetraethylammonium)

A chemical that blocks K⁺ channels, hindering repolarization and prolonging action potentials.

All-or-Nothing Principle

The principle stating that action potentials either occur fully or not at all; their strength does not vary.

Graded Potentials

Local changes in membrane potential that vary in strength and can summate but do not guarantee action potentials.

Summation

The process of combining multiple graded potentials at the trigger zone to determine if an action potential will occur.