Action Potential Propagation

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What happens to the voltage-gated Na+ channels after the threshold is reached?

They open slowly
They are inactivated
They open immediately (correct)
They remain closed

What is the primary function of the Na+-K+ pump?

To generate action potentials
To facilitate diffusion
To regulate the concentration of sodium and potassium ions (correct)
To maintain the resting potential

What happens to the 'upstream' part of the membrane after an action potential occurs?

It becomes polarized
It loses its myelin sheath
It becomes depolarized
It enters its refractory period (correct)

During the repolarization phase of an action potential, which ions move out of the cell?

Potassium ions only (A) Signup and view all the answers

What is the term for the process by which an action potential jumps from one node of Ranvier to the next in a myelinated axon?

Saltatory conduction (D) Signup and view all the answers

What is the maximum frequency of action potentials limited by?

The refractory period of the neuron (B) Signup and view all the answers

What is the direction of propagation of an action potential along the cell membrane?

Unidirectional (B) Signup and view all the answers

What is the purpose of the myelin sheath in the propagation of an action potential?

To allow the action potential to occur only at the nodes of Ranvier (C) Signup and view all the answers

What happens when an action potential reaches the end of an axon?

It is transmitted to a neighboring neuron (C) Signup and view all the answers

What is the characteristic of an action potential that describes it as an 'all-or-none' response?

The action potential has a fixed amplitude and duration (C) Signup and view all the answers

What is the term for the connection between two different neurons where the action potential is transmitted?

Synapse (B) Signup and view all the answers

What is the result of a thicker myelin sheath on the propagation of an action potential?

It increases the speed of the action potential (D) Signup and view all the answers

What occurs when the membrane potential depolarizes to threshold along the axon of a neuron?

An action potential will occur (B) Signup and view all the answers

What is the main reason why an action potential does not travel backwards?

The flow of positive charge only occurs in one direction (B) Signup and view all the answers

During the refractory period, what is true about the affected part of the membrane?

It is not sensitive to new stimuli and cannot generate another action potential (C) Signup and view all the answers

What is the primary role of sodium ions in generating an action potential?

To depolarize the membrane (D) Signup and view all the answers

What is the characteristic of an action potential that makes it an 'all or none' event?

It is an all-or-none event, meaning it either occurs completely or not at all (D) Signup and view all the answers

What is the purpose of the trigger zone in a neuron?

To start the action potential at one end of the neuron (A) Signup and view all the answers