Membrane Potential and Neuromuscular Junction Concepts

These flashcards contain key terms and definitions related to membrane potential, neuromuscular junction, and ion channel functions.

Membrane Potential

The voltage difference across a cell membrane, resulting from the distribution of ions.

Graded Potential

A transient change in membrane potential that varies in magnitude and does not follow the all-or-nothing principle.

Action Potential

A rapid, temporary change in membrane potential that propagates along the axon of a neuron or muscle fiber.

Na+-K+ ATPase

An active transport system that pumps 3 sodium ions out of the cell and 2 potassium ions into the cell, requiring ATP.

End Plate Potential (EPP)

A local depolarization of the sarcolemma that occurs at the neuromuscular junction.

Voltage-gated Sodium Channel

A type of ion channel that opens in response to changes in membrane potential, allowing Na+ ions to enter the cell.

Voltage-gated Potassium Channel

An ion channel that opens in response to depolarization and allows K+ ions to exit the cell, contributing to repolarization.

Excitatory Postsynaptic Potential (EPSP)

A graded potential that makes the postsynaptic neuron more likely to generate an action potential.

Inhibitory Postsynaptic Potential (IPSP)

A graded potential that makes the postsynaptic neuron less likely to generate an action potential.

Acetylcholine (ACh)

A neurotransmitter that binds to receptors at the neuromuscular junction, triggering muscle contraction.

Acetylcholinesterase

An enzyme that breaks down acetylcholine in the synaptic cleft, terminating its action.

Depolarization

The process of reducing the membrane potential, making the inside of the cell more positive.

Repolarization

The return of the membrane potential to its resting state following depolarization.

Hyperpolarization

An increase in the membrane potential that makes the inside of the cell more negative than the resting potential.

Tetanus Toxin

A neurotoxin that blocks the release of inhibitory neurotransmitters, causing muscle spasms.

Botulinum Toxin

A neurotoxin that blocks the release of acetylcholine, resulting in flaccid paralysis.