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9 Cards in this Set
- Front
- Back
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Describe the cardiac cycle
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~ Sino Atrial Node sends electrical impulse
~ Atria relaxes, fill with blood + contract ~ Atrial Ventricular Node receives impulse after delay ~ Bundle of His receives impulse + transports down the heart ~ Purkinji Fibres receive impulse ~ Ventricles receive impulse and contract |
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What is stroke volume?
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Volume of blood leaving the left ventricle per beat
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What is Starling's law of the heart?
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~ Greater venous return = greater contraction
The increase in blood flow into the heart is because of the increased venous return due to more blood flowing faster around the body. |
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What is cardiac output?
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The volume of blood leaving the left ventricle per minute
(Stroke volume x Heart rate) |
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How does heart rate increase?
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~ Chemoreceptors detect an increase of CO2 (therefore blood acidity too) in the blood and send an impulse to the medulla oblongata
~ A sympathetic nerve impulse is sent to the SAN ~ Cycle continues |
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How does heart rate decrease?
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~ Baroreceptors detect a drop in BP and send an impulse to the medulla
~ Parasympathetic nerve impulse sent to SAN ~ SAN slows impulse |
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What is Bradycardia?
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The reduction in the resting heart rate due to training
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What is cardiac output?
Cardiac output = stroke volume x heart rate. |
The cardiac output is the amount of blood leaving one ventricle in one minute. This increases dramatically when we exercise.
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Effects of exercise on the cardiac function?
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So exercise increases venous return, which stretches the heart during diastole and produces a corresponding increase in the force of contraction of the heart resulting in an increase in stroke volume.
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