Learn: Cardiac Cycle, Cardiac Output and Blood Pressure

Welcome!Great to see you back! Building on your knowledge of the heart and blood vessels, today we'll explore the cardiac cycle, cardiac output, and blood pressure. These concepts are key to understanding how blood is pumped and delivered throughout the body.

The Cardiac CycleThe cardiac cycle refers to the sequence of events that occur during one heartbeat. It includes three phases: diastole (relaxation and filling of the heart chambers), atrial systole (contraction of the atria), and ventricular systole (contraction of the ventricles). This cycle ensures blood flows efficiently through the heart and to the rest of the body.

Cardiac OutputCardiac output is the volume of blood pumped by the heart per minute. It is calculated using the formula:Cardiac Output = Stroke Volume × Heart RateStroke volume is the amount of blood ejected per beat, and heart rate is the number of beats per minute. Together, they determine how much blood is delivered to the body.

Blood PressureBlood pressure is the force exerted by blood against the walls of arteries. It has two measurements:Systolic pressure — the pressure during ventricular contraction.Diastolic pressure — the pressure during ventricular relaxation.Normal blood pressure is approximately 120/80 mmHg (systolic/diastolic).

Factors Affecting Blood PressureBlood pressure can be influenced by several factors, including:Age — Blood pressure tends to rise with age.Diet — High salt intake can increase blood pressure.Exercise — Regular activity helps lower blood pressure.Stress — Prolonged stress can elevate blood pressure.

Review Time!Fantastic work! You've learned about the cardiac cycle, cardiac output, and blood pressure. Let's test your understanding now.