Final answer:
Systole refers to the contraction phase of the heart.
Step-by-step explanation:
The cardiac cycle consists of two main phases: systole and diastole. Systole represents the contraction of the heart muscle, specifically the ventricles, leading to the ejection of blood into the pulmonary artery from the right ventricle and into the aorta from the left ventricle.
This phase is crucial for pumping oxygenated blood to the body and deoxygenated blood to the lungs. The contraction of the heart is initiated by electrical impulses, leading to the mechanical contraction of the myocardium.
During systole, the pressure in the arteries increases as blood is forcefully ejected from the contracting ventricles into the aorta. This results in a rise in blood pressure, which is typically measured as systolic blood pressure. The systolic pressure is the higher of the two values in a blood pressure reading, representing the pressure in the arteries during the heart's contraction phase. Understanding systolic and diastolic blood pressure values is essential in assessing cardiovascular health and diagnosing conditions such as hypertension.
In summary, systole is the contraction phase of the heart, during which blood is pumped out of the ventricles into the systemic and pulmonary circulations. This phase is integral to maintaining blood flow and delivering oxygen to the body's tissues. The corresponding increase in arterial pressure during systole is a vital component of blood pressure readings and cardiovascular health assessments.