Learn: Cardiac Cycle, Cardiac Output and Blood Pressure

Welcome!Building on what you've already learned about the heart and blood vessels, let's explore how the heart works to pump blood, how cardiac output is calculated, and how blood pressure is regulated.

What is the Cardiac Cycle?The cardiac cycle is the sequence of events that occurs during one heartbeat. It includes the contraction (systole) and relaxation (diastole) of the heart chambers. This cycle ensures blood is pumped efficiently around the body.

Phases of the Cardiac CycleThere are three main phases: atrial systole (atria contract), ventricular systole (ventricles contract), and diastole (heart relaxes). Blood flows through the heart due to pressure changes during these phases.

What is Cardiac Output?Cardiac output is the volume of blood pumped by the heart per minute. It is calculated using the formula: Cardiac Output = Heart Rate × Stroke Volume. This measurement helps understand how well the heart is functioning.

What is Blood Pressure?Blood pressure is the force exerted by circulating blood on the walls of arteries. It is measured as two values: systolic pressure (during ventricular contraction) and diastolic pressure (during heart relaxation).

How is Blood Pressure Controlled?Blood pressure is regulated by the nervous system and hormonal mechanisms. Baroreceptors detect changes in pressure and signal the brain to adjust heart rate and vessel diameter.

Review Time!Great work! You've learned about the cardiac cycle, cardiac output, and blood pressure. Now let's test your understanding with a few questions.