Systole refers to the of the heart.
A Relaxation
B Filling
C Contraction
D Depolarization
E Repolarization
The correct answer and explanation is:
The correct answer is C. Contraction.
Systole refers to the phase of the heart’s cycle when the heart muscle contracts to pump blood out of the chambers. This phase is in contrast to diastole, which is the phase when the heart relaxes and fills with blood.
During systole, the ventricles contract, creating pressure that forces the blood through the pulmonary artery to the lungs and through the aorta to the rest of the body. The contraction of the ventricles is essential for maintaining the flow of blood and ensuring that oxygenated blood reaches the tissues and organs.
The process starts with the electrical impulses from the sinoatrial (SA) node, which triggers atrial contraction (atrial systole). This is followed by the contraction of the ventricles. The right ventricle pumps deoxygenated blood to the lungs, while the left ventricle pumps oxygenated blood to the rest of the body.
The pressure generated during systole is crucial for maintaining the circulatory system’s function. It is also used to define a person’s blood pressure. The top number in a blood pressure reading is the systolic pressure, which measures the pressure in the arteries when the heart contracts.
Systole is influenced by factors such as heart rate, blood volume, and the force of the heart’s contraction. Disruptions in systolic function, such as those seen in heart failure, can lead to decreased cardiac output, which can cause a range of health problems. Therefore, systole is vital for normal circulatory function and overall cardiovascular health.