1. Physical Education Studies
The Cardiac Cycle
Physical Education Studies
The Cardiac Cycle
MSC PES 1A
MSC PES 1A

2. CARDIAC OUTPUT = Stroke Volume x Beats per Minute
Definitions
Stroke Volume: The amount of blood the heart pumps out with each beat.
Cardiac Output: The amount of blood that the heart is able to circulate in one minute.
CARDIAC OUTPUT = Stroke Volume x Beats per Minute
MSC PES 1A

3. Boston Scientific : Heart & Blood Vessel Basics
The Cardiac Cycle
The heart muscle contracts rhythmically with a period of relaxation between each beat. Not all parts contract at the same time.
There is an orderly sequence of contractions that begins in the atria and pass to the ventricles.
Boston Scientific : Heart & Blood Vessel Basics
MSC PES 1A

4. Diastole
Relax Time!!!
Muscles of both atria and ventricles relax to allow blood from veins to flow through the atria into the ventricles until heart is filled.
What stops back flow????
MSC PES 1A

5. Systole
Contract Time!!!
Atrial Systole: Atria contract and force blood into ventricles.
Ventricular Systole: Ventricles contract and force blood into arteries under pressure.
At the same time the atria relax and the cycle starts again!
MSC PES 1A

6. Circulation of Blood Around the Body
The cardiac cycle comprises 2 circulations since the right and left sides of the heart function separately as 2 pumps:
Pulmonary Circulation: R side receives deO2 from the body and pumps to the lungs.
Systemic Circulation: L side receives O2 blood from the lungs and pumps to the body.
Can you name vessels involved in this process??
MSC PES 1A

7. Blood Pressure
Blood Pressure is the force exerted by the blood against the artery walls as it is pumped around the body.
The pressure in the arteries rises at contraction (systolic pressure) and falls during refill (diastolic pressure).
MSC PES 1A

8. Changes in Blood Pressure
Changes in body position
Physical Exertion
Can you think of any more??
When would it be at its lowest?
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9. Measuring Blood Pressure
Measured using a sphygmomanometer.
The manual version consists of an inflatable cuff, a rubber bulb, and a pressure gauge (see opposite).
MSC PES 1A

10. Measuring Blood Pressure
BP is measured in millimetres of mercury (mmHG). Reading are recorded as fraction, eg. 120/80.
The higher number represents systolic pressure, and the lower one diastolic pressure.
According to World Health Organisation, normal blood pressure is considered to be 140/90 or less.
MSC PES 1A

11. Hypertension Chronic or high blood pressure.
Occurs when there is an increased pumping of the heart and a narrowing of the arterioles.
Can lead to serious illness and be life threatening.
MSC PES 1A