Learn: Cardiac Cycle, Cardiac Output and Blood Pressure

Welcome!You've already learned about the heart and blood vessels. Now, we'll explore how the heart works during each beat, how it produces the blood flow needed for your body, and how pressure is regulated.

The Cardiac CycleThe cardiac cycle describes the sequence of events in one heartbeat. It includes two main phases: systole (contraction) and diastole (relaxation). During systole, blood is pushed out of the heart, and during diastole, the heart fills with blood.

Heart SoundsThe 'lub-dub' sound of the heart is caused by the closing of valves during the cardiac cycle. The 'lub' is the closing of the atrioventricular (AV) valves, and the 'dub' is the closing of the semilunar valves.

Cardiac OutputCardiac output is the volume of blood the heart pumps per minute. It depends on two factors: stroke volume (amount of blood pumped per beat) and heart rate (number of beats per minute). The formula is: Cardiac Output = Stroke Volume × Heart Rate.

Blood PressureBlood pressure is the force exerted by blood on the walls of blood vessels. It is measured in two values: systolic pressure (pressure during heart contraction) and diastolic pressure (pressure during heart relaxation).

Review Time!Great work! You've learned about the cardiac cycle, cardiac output, and blood pressure. Let’s test your understanding with some questions.