What role does the cardiac cycle play in blood pressure changes?

The cardiac cycle is integral to understanding blood pressure changes because it involves the rhythmic contraction and relaxation of the heart, which influences the force exerted on the walls of blood vessels. As the heart contracts during systole, it pumps blood out of the ventricles and into the arteries, causing an increase in blood pressure. This is known as systolic pressure, which is the highest pressure in the arteries during the cardiac cycle.

Conversely, during diastole, when the heart muscle relaxes and the chambers fill with blood, the pressure in the arteries decreases. This is referred to as diastolic pressure, which is the lowest arterial pressure. Therefore, the cardiac cycle directly regulates the pressure exerted on blood vessels by alternately increasing and decreasing the volume of blood flowing into them with each heartbeat, thus creating the oscillations of blood pressure that are essential for proper circulation.

The other options do not accurately capture the cardiac cycle's role in blood pressure. For example, while blood viscosity can influence blood pressure, it is not directly affected by the phases of the cardiac cycle. Similarly, the pulse rate is a separate physiological measurement related to heartbeats per minute, rather than a direct consequence of the cardiac cycle's impact on blood pressure. Lastly,