Learn: Cardiac Cycle, Cardiac Output and Blood Pressure

Welcome!Today we'll learn about the cardiac cycle, cardiac output, and blood pressure. These are key topics in understanding the cardiovascular system. Let's explore how the heart works step by step!

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

Phases of the Cardiac CycleThe cycle has two main phases: systole (when chambers contract) and diastole (when chambers relax). During systole, blood is pushed out of the heart, and during diastole, the heart fills with blood.

Cardiac OutputCardiac 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 us understand how efficiently the heart is working.

What is Blood Pressure?Blood pressure is the force of blood against the walls of arteries. It is measured in two values: systolic pressure (when the heart contracts) and diastolic pressure (when the heart relaxes). Healthy blood pressure ensures efficient blood flow.

How Blood Pressure is MeasuredBlood pressure is measured using a sphygmomanometer. The values are recorded in millimetres of mercury (mmHg). A typical reading might be 120/80 mmHg, with 120 being systolic pressure and 80 being diastolic pressure.

Factors Affecting Blood PressureBlood pressure can be influenced by factors like stress, exercise, diet, and age. High blood pressure (hypertension) can increase the risk of heart disease.

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