diastolic depolarization
Quick Summary
Diastolic depolarization refers to the phase in the cardiac cycle where the heart muscle relaxes and chambers fill with blood. This process is crucial for the heart's rhythmic contractions, which are not externally controlled but originate intrinsically within the cardiac muscle.123
The heart's electrical impulse travels from the atria to the ventricles, causing depolarization. This involves the flow of ions across the cell membrane, leading to muscle contraction. Specialized pacemaking cells, particularly in the sinoatrial node, exhibit spontaneous depolarization, setting the heart rate. The rate of this spontaneous depolarization is a key determinant of heart rate.24
Factors like ion concentration and certain drugs can affect this process. The depolarization event also triggers calcium influx, which is essential for excitation-contraction coupling, enabling the heart muscle to contract and pump blood effectively.23
Ask Britannica AI about this topic
Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.
