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Cardiac Output: PowerPoint Presentation
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Cardiac Output:

Cardiac Output:

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Cardiac Output:

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  1. Cardiac Output: And Influencing Factors

  2. Cardiac Output • Amount of blood pumped out by each ventricle in 1 min • CO = HR x SV

  3. Cardiac Reserve • The difference between resting and maximal CO

  4. Stroke Volume • SV = EDV – ESV • EDV (volume of blood in ventricle after diastole) • ESV (volume of blood remaining in ventricle after contraction) • With each beat, ~ 60% of blood in chambers is emptied

  5. Frank-Starling law of the heart • Preload = critical factor in determining SV

  6. Preload • Degree to which cardiac cells are stretched before contraction • Optimal length determined by: • If max # of cross bridge attachments occur • If max force of contraction occurs

  7. Venous Return • The volume of blood returning to heart and stretching ventricles • If venous return increases, EDV increases; therefore SV increases • Left and right ventricles have equal venous return; therefore blood does not “pool” or backflow in heart

  8. Contractility • Contractile strength of heart (due to increased CA2+) • Causes increased release of blood (therefore lower ESV)

  9. Afterload • Force to eject blood from ventricles • Constant in healthy people; lower in people with hypertension (therefore increases ESV and decreases SV)