Chapter48 Neurons, Synapses, and Signaling

Front

What is the membrane potential?

Back

The membrane potential is the electrical potential difference across a cell's membrane, primarily determined by the distribution of ions, particularly sodium (Na+) and potassium (K+).

Front

What is the equilibrium potential for potassium?

Back

The equilibrium potential for potassium (E_K) is the membrane potential at which the net flow of K+ ions across the membrane is zero, typically around -90 mV in neurons.

Front

What is a resting potential in a neuron?

Back

The resting potential is the stable, negative charge of a neuron when it is not actively sending signals, usually around -70 mV.

Front

What does it mean for a neuron to exhibit a resting potential that is more negative than the threshold potential?

Back

It means that the neuron's membrane potential is lower than the level required to trigger an action potential, making it less likely to fire.

Front

What is the threshold potential?

Back

The threshold potential is the critical level to which a membrane potential must be depolarized to initiate an action potential, typically around -55 mV.

Front

What are voltage-gated sodium channels?

Back

Voltage-gated sodium channels are membrane proteins that open in response to depolarization, allowing Na+ ions to flow into the neuron, contributing to the rising phase of an action potential.

Front

What are voltage-gated potassium channels?

Back

Voltage-gated potassium channels open in response to depolarization and allow K+ ions to flow out of the neuron, helping to repolarize the membrane after an action potential.

Front

What is the role of acetylcholine in motor neurons?

Back

Acetylcholine is a neurotransmitter released by motor neurons that stimulates muscle contraction by binding to receptors on muscle cells.

Front

What is a simple nervous system?

Back

A simple nervous system is characterized by a basic organization of neurons and ganglia, allowing for information flow both toward and away from an integrating center.

Front

What is the significance of ganglia in a nervous system?

Back

Ganglia are clusters of neuronal cell bodies that process information and relay signals in a nervous system, playing a crucial role in reflexes and motor control.