What occurs during the plateau phase of the cardiac action potential?
Understand the Problem
The question is asking about the physiological changes that occur during the plateau phase of the cardiac action potential, specifically relating to the movement of calcium and potassium ions across the cell membrane.
Answer
The plateau phase is sustained by calcium influx, allowing prolonged muscle contraction.
During the plateau phase of the cardiac action potential, there is a sustained depolarization. This phase is mainly maintained by the influx of calcium ions (Ca2+) through L-type calcium channels, and it allows for a longer muscle contraction, giving time for cardiac muscle cells to depolarize, ensuring a strong and coordinated contraction.
Answer for screen readers
During the plateau phase of the cardiac action potential, there is a sustained depolarization. This phase is mainly maintained by the influx of calcium ions (Ca2+) through L-type calcium channels, and it allows for a longer muscle contraction, giving time for cardiac muscle cells to depolarize, ensuring a strong and coordinated contraction.
More Information
The plateau phase is critical for the proper timing of heartbeats, and disruptions can cause cardiac arrhythmias.
Tips
A common mistake is thinking sodium ions sustain the plateau phase. It's primarily calcium ions through L-type calcium channels.
Sources
- Cardiac Action Potential - Wikipedia - en.wikipedia.org
- Cardiac Action Potential - an overview | ScienceDirect Topics - sciencedirect.com
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