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Questions and Answers
What is the total time duration of one complete cardiac cycle?
What is the total time duration of one complete cardiac cycle?
During which phase of the cardiac cycle does the first heart sound (S1) occur?
During which phase of the cardiac cycle does the first heart sound (S1) occur?
What happens to the atrial pressure during ventricular contraction?
What happens to the atrial pressure during ventricular contraction?
What is the volume of blood ejected from each ventricle during one cardiac cycle?
What is the volume of blood ejected from each ventricle during one cardiac cycle?
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Which event signifies the closure of the semilunar valves during the cardiac cycle?
Which event signifies the closure of the semilunar valves during the cardiac cycle?
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What occurs during the isometric contraction phase of ventricular systole?
What occurs during the isometric contraction phase of ventricular systole?
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Which pressure is associated with the rapid ejection phase of ventricular systole?
Which pressure is associated with the rapid ejection phase of ventricular systole?
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Which event leads to the closure of the semilunar valves during the cardiac cycle?
Which event leads to the closure of the semilunar valves during the cardiac cycle?
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What is the approximate end systolic volume (ESV) remaining in each ventricle after ejection?
What is the approximate end systolic volume (ESV) remaining in each ventricle after ejection?
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During which phase does atrial pressure exhibit a gradual increase due to venous return?
During which phase does atrial pressure exhibit a gradual increase due to venous return?
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Study Notes
The Cardiac Cycle
- The events that occur during one heartbeat (systole & diastole)
- Takes about 0.8 seconds (60/75)
- Divided into ventricular systole (0.3s), ventricular diastole (0.5s), atrial systole (0.1s) and atrial diastole (0.7s)
Ventricular Systole
- Ventricular contraction causes immediate closure of the AV valves, creating the first heart sound (S1)
-
Isometric Contraction Phase: Ventricles contract isometrically with all four valves closed
- Atrial pressure increases (c wave)
- Semilunar valves open (at 80 or 10 mmHg) leading to rapid ejection of blood from the ventricles
- Pressures continue to rise within the ventricles (reaching 120 or 25 mmHg)
- Stroke volume (70 ml) is ejected from each ventricle
- 50 ml remain in each ventricle, known as the End Systolic Volume (ESV)
- Atrial pressure decreases due to ventricular shortening, then increases due to venous return
- Aortic and pulmonary pressures increase due to ejected blood
- Atrial pressure continues to increase (v wave)
Ventricular Diastole
- Ventricular relaxation leads to a reduction in pressure, causing closure of the semilunar valves and producing the second heart sound (S2)
The Cardiac Cycle
- The events during one heartbeat (systole and diastole)
- Lasts about 0.8 seconds
- Divided into ventricular systole, ventricular diastole, atrial systole and diastole
Ventricular Systole
- Contraction of the ventricles
- Closes the AV valves
- Produces the first heart sound (S1)
- Isometric contraction phase:
- Pressure continues to increase while all 4 valves are closed
- Atrial pressure increases (c wave)
- Semilunar valves open at 80 or 10 mmHg
- Rapid ejection of blood
- Maximum pressure of 120 or 25 mmHg
- Stroke Volume: 70 ml
- Atrial pressure decreases initially, then increases (venous return)
- Aortic and pulmonary pressures increase
- End Systolic Volume (ESV): 50 ml
- Atrial pressure continues to increase (v wave)
Ventricular Diastole
- Ventricular relaxation
- Ventricular pressure decreases
- Closes the semilunar valves
- Produces the second heart sound (S2)
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Description
Explore the intricate events that occur during a heartbeat in this quiz on the cardiac cycle. Understand the phases of systole and diastole, and learn about the mechanics of ventricular contraction and atrial pressure changes. This quiz will enhance your knowledge of cardiovascular physiology.
