What is the action potential initially generated?

What is the action potential initially generated?

Where in the neuron is an action potential initially generated? Axon hillock. this region (first part of the axon) receives local signals (graded potentials) from the soma and dendrites and has a high concentration of voltage-gated Na+ channels.

Which ion is responsible for the repolarization phase of the action potential?

potassium

What is responsible for the repolarization phase of an action potential quizlet?

Voltage-gated sodium channels begin to inactivate (close) and voltage-gated potassium channels begin to open. The repolarization phase of the action potential involves decreasing sodium influx via inactivation of sodium channels and increasing potassium efflux (exit) via opening potassium channels.

Which of the following is responsible for repolarization of the nerve cell?

Explanation: Potassium is the major species that repolarizes a neuron following depolarization. After sodium has entered the cell to create depolarization, repolarization is driven by potassium ion efflux.

Which channels are responsible for the depolarization phase of the action potential?

As we have seen, the depolarization and repolarization of an action potential are dependent on two types of channels (the voltage-gated Na+ channel and the voltage-gated K+ channel).

What is more likely to promote an action potential?

A small, local depolarization called an EPSP moves the membrane potential closer to threshold. If threshold is reached, an action potential is triggered. Thus, an EPSP is more likely to promote an action potential while an IPSP is less likely to promote an action potential.

How do action potentials travel?

The action potential travels down the axon as the membrane of the axon depolarizes and repolarizes. Nodes of Ranvier are gaps in the myelin along the axons; they contain sodium and potassium ion channels, allowing the action potential to travel quickly down the axon by jumping from one node to the next.

How fast do action potentials travel down an axon?

about 1 meter/sec

What is the main function of the sodium potassium pump?

It acts to transport sodium and potassium ions across the cell membrane in a ratio of 3 sodium ions out for every 2 potassium ions brought in. In the process, the pump helps to stabilize membrane potential, and thus is essential in creating the conditions necessary for the firing of action potentials.