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Circulation and Immunity. Cardiovascular System. The system consisting of the heart, blood vessels and blood that circulates through the body. Cardiovascular System. The human circulatory system performs four key functions.
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Cardiovascular System • The system consisting of the heart, blood vessels and blood that circulates through the body.
Cardiovascular System • The human circulatory system performs four key functions. • It transports and delivers oxygen and nutrients (e.g. minerals, vitamins, and glucose) to the body’s cells in exchange for carbon dioxide and wastes. • It transports chemical messengers, such as hormones throughout the body. • It distributes heat • It defends against disease
Cardiac Output • Cardiac Output is the volume of blood pumped by the heart in one minute, which is equal to the product of stroke volume and heart rate.
Average Values • The average human male pumps out 70mL of blood per beat (60 mL for females) with an average resting heart rate is around 72 beats per minute.
Example Question • A typical human male has a stroke volume of 70 mL per beat and a resting heart rate of 72 beats per minute. • A. Calculate the cardiac out put. Express your answer in litres per minute. • B. Calculate the volume of blood that would be pumped in one day based upon the cardiac output.
Example Question • A typical human male has a stroke volume of 70 mL per beat and a resting heart rate of 72 beats per minute. • A. Calculate the cardiac out put. Express your answer in litres per minute. • Solution. • Stroke volume = 70 mL/beat • 70 mL x 1/1000mL = 0.070 L/beat
Example Question • A typical human male has a stroke volume of 70 mL per beat and a resting heart rate of 72 beats per minute. • Solution. • Cardiac output (stroke volume)x(heart rate) • =(0.070 L/beat)x 72 (beats/min) = 5.04 L/min • In one day 5.04 L/min x 1440 min/day • = 7257.6 L = 7.3 x 103 L/day
Heart Beat • Diastole - the phase of the heart’s cycle where a chamber of the heart, either an atrium or a ventricle, relaxes and fills with blood. Semilunar valves closed - “dub” sound produced • Systole - the phase of the heart’s cycle when the ventricles contract to eject blood from within the chamber. AV vales closed - “lub” sound produced.
Factors Affecting Heart Rate • Emotions ie. Fear anxiety • External temperature. Hotter = Higher HR • Activity level. • Age. Older you get the lower your max HR • Fitness level. • Medical conditions.
Target Hear Rate for Exercise • Your maximum heart rate is approximately 220 - your age.