Neurons: Steps of Action Potential

Questions and Answers

What is the first step of the action potential?

Hyperpolarization

Resting Potential

Reaching Threshold (correct)

Depolarization

What occurs during Step Two of the action potential?

More sodium channels open and sodium ions rush into the cell membrane.

During Step Three, potassium channels close while sodium channels open.

False

What happens during Step Four of the action potential?

Active sodium and potassium pumps begin to start repolarization. Signup and view all the answers

What is the outcome of Step Five, Hyperpolarization?

Both B and C Signup and view all the answers

What characterizes Step Six in the action potential process?

The neuron returns to resting potential of -70 mV. Signup and view all the answers

Study Notes

Steps of Action Potential

Step One: Reaching Threshold
- A stimulus affects the dendrites of a nerve cell.
- Inner potential shifts from -70 mV to -55 mV, reaching the threshold for action potential.
Step Two: Depolarization
- Sodium channels open, allowing sodium ions to rapidly enter the cell membrane.
- Membrane potential increases from -55 mV to +30 mV due to sodium influx.
Step Three: Sodium Channels Close and Potassium Channels Open
- Sodium channels close after depolarization.
- Potassium channels take longer to open, completing the depolarization phase.
Step Four: Active Sodium and Potassium Pumps Begin to Start Repolarization
- With potassium channels open, the membrane potential starts returning to its resting state.
- Membrane potential moves back to -70 mV.
Step Five: Hyperpolarization
- Repolarization may overshoot the resting potential, reaching around -90 mV.
- This overshoot prevents the neuron from being stimulated too soon.
Step Six: Resting Potential
- Sodium and potassium pumps restore the neuron’s potential back to -70 mV.
- Neuron is now capable of responding to new stimuli.

Description

This quiz focuses on the crucial steps involved in the action potential of neurons. It covers topics such as reaching threshold and depolarization, essential for understanding neural communication. Perfect for students studying neuroscience or biology.