Cardiac Cycle

  1. What is Diastole?
    Ventricular filling and a brief period just prior to filling at which time the ventricles are relaxing
  2. What is Systole?
    Time of contraction and ejection of blood from the ventricles.
  3. What happens during the "a" wave and how does it appear on a cardiac cycle graph?
    • An atrium contracting at the end of diastole, causing a small rise in both atrial and ventricular pressure.
    • Small rise and fall right before huge increase in LVP 
  4. Atrial Contraction phase...which valve is open, which valve is closed, and why?
    • Mitral valve is open (LAP > LVP)
    • Aortic valve is closed (AP > LVP) 
  5. What increases during Isovolumetric Contraction Phase? Is it a large increase or a small increase?
    Left Ventrical Pressure SKYROCKETS
  6. What is a "c" wave?
    Small rise in atrial pressure curve due to bulging of mitral valve into atrium when ventrical begins to contract.
  7. What closes during Isovolumetric Contraction Phase and what is the clinical significance of this?
    • Mitral Valve is closing and this creates the S1 "lub" heart sound. Aortic valve is still closed.
    • Tricuspid Valve is also closing. 
  8. During Isovolumetric Contraction Phase, is the aortic valve open or closed, and why?
    Closed -> Aortic pressure is still much greater than Left Ventricle Pressure
  9. What is the LVEDV?
    • Left Ventricle End-Diastolic Volume
    • Plateau on graph of LV vol, volume of blood remaining in ventricle during isovolumetric contraction
  10. What is happening in the Rapid Ventricular Ejection phase?
    Left ventricle contracts and LV pressure exceds aortic pressure. Aortic valve opens and blood is forced from ventricle out into aorta and LV volume decreases.
  11. What must occur in the left ventricle during ejection of blood to keep valve open and blood ejecting?
    Pressure in ventricle must also be increasing along with aortic pressure bc it must be greater to keep blood flowing into aorta.
  12. What is happening in the Slow Ventricular Ejection Phase?
    There is a reduced # of contracting cardiomyocytes...Left Ventricle ejection begins to slow down due to reduced ventricular pressure. LVP and AP decrease, LV Volume slightly decreases.
  13. What makes the aortic valve shut and in what phase does this shut?
    When ventricular pressure falls below the pressure in the aorta towards the end of the Slow Ventricular Ejection Phase
  14. In what phase does Diastole begin?
    Isovolumetric Relaxation Phase
  15. What is LVESV?
    Left Ventricular End Systolic Volume -> unchanging volume that remains in the ventricle after ejection and during relaxation. Roughly 50mL
  16. What closes during Isovolumetric Relaxation Phase, why does it close and what is the clinical significance of this?
    Aortic Valve closes because the LVP falls below the AP. This closing creates the second heart sound, S2.
  17. What is the Dicrotic Notch?
    • Aortic pressure undergoing a small fluctuation which is due to the movement of blood within aorta backwards toward the closed aortic valve. (due to Windkessel Effect).
    • Dicrotic Notch occurs in the Isovolumetric Relaxation Phase
  18. At the end of relaxation, the left ventricular pressure continues to fall until what happens?
    Mitral valve opens
  19. What is the "v" wave?
    Pressure of left atrium rising to a peak due to atrial filling in Isovolumetric Relaxation Phase
  20. What is happening during Rapid Ventricular Filling Phase?
    Left atrial pressure exceeds the left ventricular pressure due to ventricular relaxation -> Mitral valve opens
  21. What is simultaneously happening in the aorta during Rapid Ventricular Filling Phase?
    Pressure is falling because blood is leaving the aorta for distribution into the peripheral tissues.
  22. What is another name for the Slow Ventricular Filling Phase?
    Diastesis (passive filling)
Card Set
Cardiac Cycle
Cardiovascular Physio.