Flashcards in Cardiac Cycle Deck (23):
The relaxation and filling of the ventricles
What is the approximate stroke volume?
What is the approximate duration of a single cardiac contraction?
How is cardiac muscle arranged on a gross level?
In a figure of 8 so that it contracts from the base upwards.
What prevents inversion of atrioventricular valves?
The cusps attach to papillary muscles via chordae tendinae
Approximately how long is the signal delayed at AVN for?
What are the 7 phases of the cardiac cycle?
1: Atrial contraction
2: Isovolumetric contraction
3. Rapid ejection
4. Reduced ejection
5. Isovolumetric relaxation
6. Rapid filling
7. Reduced filling
Which phases of the cardiac cycle occur is systole?
2, 3 and 4
Approximately how long does the full cardiac cycle take?
Approximately how much time is spent in systole and how much in diastole?
What do we plot in a Wiggers diagram?
What is the A wave in atrial pressure?
The rise in atrial pressure due to atrial systole.
What is the approximate end diastolic volume?
What causes the C wave in atrial pressure?
Closing of the mitral valve
In which phase does S1 occur?
Phase 2: the atrioventricular valves close to begin systole
What causes the X descent in atrial pressure?
The atrial pressure initially decreasing as the atrial base is pulled as the ventricle contracts.
What causes the V wave in atrial pressure?
Gradual rise of pressure due to continued venous return from the lungs.
What is the approximate end systolic volume?
How do we work out stroke volume?
EDV - ESV
In which phase is the second heart sound?
Phase 5: outflow valves close as systole is finished
What causes the Y descent in atrial pressure?
Fall in atrial pressure due to the opening of the atrioventricular valves.
What can cause a normal 3rd heart sound?
We can hear ventricular filling