What is the term for the relaxation of heart muscle?

The term for the relaxation of heart muscle is diastole. During diastole, the heart chambers, specifically the atria and ventricles, relax and fill with blood. This phase is essential for allowing adequate blood volume to enter the heart, preparing it for the subsequent contraction phase known as systole.

Diastole includes several sub-phases, but the key aspect is the overall relaxation of the myocardium which permits the chambers to enlarge and receive blood from the body and lungs. Understanding diastole is crucial for grasping how the heart functions in a rhythmic and coordinated manner, maintaining an effective cardiac cycle that supports blood circulation throughout the body.