The volume of blood ejected from the left ventricle per beat.
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What is cardiac output?
The volume of blood ejected from the left ventricle per minute.
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What is stroke volume dependent on?
Venous return and ventricular elasticity / contractility.
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What is venous return?
The return of the blood to the right atria through the veins.
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What is ventricular elasticity / contractility?
The degree of stretch in the cardiac muscle fibres. The greater the stretch the greater the force of contraction, which will raise SV.
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What is sub-maximal exercise?
Low-to-moderate intensity within a performer's aerobic capacity or below the anaerobic threshold.
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What is maximal exercise?
A high intensity above a performer's aerobic capacity, which will take a performer to exhaustion.
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Heart rate response to exercise
Heart rate increases in proportion to the intensity of exercise until we approach our maximum.
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HR sub-maximal response
Anticipatory rise (release of adrenaline); rapid increase in HR to increase blood flow and oxygen delivery; plateau as oxygen supply meets the demand; rapid decrease in HR then more gradual back to resting.
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HR maximal response
Anticipatory rise; rapid increase in HR; does NOT plateau as exercise intensity continues to increase and there is still a growing demand for oxygen and waste removal.
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Stroke volume response to exercise
Stroke volume increases in proportion to exercise intensity until a plateau is reached at 40-60% of working capacity (corresponds to sub-maximal intensity exercise)
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What does it reach a plateau?
It reaches a plateau because the increased HR during maximal intensity does not allow enough time for the ventricles to completely fill with blood in the diastolic phase, limiting the Frank-Starling Mechanism.
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What is the Frank-Starling Mechanism?
Shows how SV is dependent on venous return due to increased volume of blood returning to the heart leading to an increased end-diastolic volume in the ventricles.
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What is important about an increased end-diastolic volume (see previous)
Creates a greater stretch on the ventricle walls which increases the force of ventricular contraction, ejecting a larger volume of blood from the ventricles.
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Cardiac output response to exercise
Increases in line with exercise intensity and plateaus during maximal exercise.
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Other cards in this set
Card 2
Front
What is stroke volume?
Back
The volume of blood ejected from the left ventricle per beat.
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