What does one complete cardiac cycle consist of?

One complete cardiac cycle is defined as the sequence of events that occur during one heartbeat, which includes both the contraction and relaxation of the heart chambers. This cycle encompasses the processes of systole (contraction) and diastole (relaxation) for both the atria and the ventricles. During this cycle, blood is pumped from the heart into the circulatory system while simultaneously allowing the chambers to refill with blood, ensuring efficient circulation.

The focus on contraction and relaxation highlights the dynamic process of the heart as it maintains its rhythm and function. Although other options mention aspects of the cardiac cycle, they do not fully encompass the complete cycle's definition or miss critical components of the process. Understanding the full scope of a cardiac cycle is vital for recognizing how changes can affect cardiovascular function and overall health.