Biological Systems MCAT Practice Exam

What best describes systolic pressure?

1. The pressure in arteries when the heart is relaxed

2. The pressure in arteries when the ventricles pump blood

3. The pressure when blood flow is at its lowest

4. The average pressure in the circulatory system

The correct answer is: The pressure in arteries when the ventricles pump blood

Systolic pressure is defined as the pressure in the arteries during the phase of the heartbeat when the heart's ventricles contract and pump blood out into the circulatory system. This action creates a surge of blood that raises the pressure in the arteries, which is measured and referred to as systolic pressure. This definition aligns well with the understanding of how the cardiac cycle operates: during ventricular contraction, blood is ejected into the aorta and systemic circulation, resulting in the highest arterial pressure in the cardiac cycle. Recognizing this physiological process helps to clarify why during times of ventricular contraction, when blood volume in the arteries is maximized, systolic pressure reaches its peak.