What happens when the myocardium is stimulated?

When the myocardium is stimulated, it experiences contraction. This is primarily due to the influx of calcium ions into the cardiac muscle cells, which triggers the sliding of actin and myosin filaments—a process fundamental to muscle contraction. The electrical stimulation that originates from the heart's conduction system, particularly the Sinoatrial (SA) node, spreads through the atria and ventricles, leading to a coordinated contraction of the entire myocardium.

The contraction of the myocardium results in the pumping action of the heart, effectively pushing blood out of the heart chambers and into the circulatory system. This is essential for maintaining blood flow and ensuring that oxygen and nutrients reach tissues throughout the body.

Understanding this contraction mechanism is crucial for interpreting various EKG patterns and recognizing abnormalities in cardiac function, emphasizing the significance of myocardial stimulation in the overall functioning of the heart.