Podcast
Questions and Answers
During which phase of the cardiac cycle does the left ventricular volume decrease from 135mL to 65mL?
During which phase of the cardiac cycle does the left ventricular volume decrease from 135mL to 65mL?
Which of the following events occurs immediately after the aortic valve closes?
Which of the following events occurs immediately after the aortic valve closes?
Which of the following heart sounds is associated with the closing of the semilunar valves?
Which of the following heart sounds is associated with the closing of the semilunar valves?
During which phase of the cardiac cycle does the mitral valve open?
During which phase of the cardiac cycle does the mitral valve open?
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Which of the following represents the end-diastolic volume of the ventricle?
Which of the following represents the end-diastolic volume of the ventricle?
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What action is responsible for a small amount of additional blood entering the ventricles during the cardiac cycle?
What action is responsible for a small amount of additional blood entering the ventricles during the cardiac cycle?
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Which statement accurately describes the relationship between pressure and blood flow during the cardiac cycle?
Which statement accurately describes the relationship between pressure and blood flow during the cardiac cycle?
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Which of the following is NOT a general principle of the cardiac cycle?
Which of the following is NOT a general principle of the cardiac cycle?
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During which phase of the cardiac cycle do the semilunar valves snap closed?
During which phase of the cardiac cycle do the semilunar valves snap closed?
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What is the primary function of the SA node in the cardiac cycle?
What is the primary function of the SA node in the cardiac cycle?
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Which of these describes an event that occurs during late diastole?
Which of these describes an event that occurs during late diastole?
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What happens during isovolumic ventricular relaxation?
What happens during isovolumic ventricular relaxation?
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Why is the heart considered a biological pump?
Why is the heart considered a biological pump?
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Which of the following describes the event represented by point 'B' in the graph?
Which of the following describes the event represented by point 'B' in the graph?
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What does the 'Dicrotic notch' in the Wiggers diagram indicate?
What does the 'Dicrotic notch' in the Wiggers diagram indicate?
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Which event corresponds with the upward deflection marked 'E' in the graph?
Which event corresponds with the upward deflection marked 'E' in the graph?
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Which phase of the cardiac cycle corresponds to the period between points 'C' and 'D'?
Which phase of the cardiac cycle corresponds to the period between points 'C' and 'D'?
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Which of the following is TRUE regarding the relationship between left ventricular pressure and left ventricular volume during the period represented by 'F' in the graph?
Which of the following is TRUE regarding the relationship between left ventricular pressure and left ventricular volume during the period represented by 'F' in the graph?
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The interval between the first heart sound (S1) and the second heart sound (S2) represents which phase of the cardiac cycle?
The interval between the first heart sound (S1) and the second heart sound (S2) represents which phase of the cardiac cycle?
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During isovolumic ventricular relaxation, which of the following is TRUE?
During isovolumic ventricular relaxation, which of the following is TRUE?
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Which of the following contributes to the peak of the 'Aorta' pressure curve in the Wiggers diagram?
Which of the following contributes to the peak of the 'Aorta' pressure curve in the Wiggers diagram?
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Which event of the cardiac cycle MOST closely corresponds to the 'P' wave in the ECG?
Which event of the cardiac cycle MOST closely corresponds to the 'P' wave in the ECG?
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What does the area enclosed by the pressure volume (PV) loop represent?
What does the area enclosed by the pressure volume (PV) loop represent?
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What happens to the PV loop if the heart rate increases?
What happens to the PV loop if the heart rate increases?
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What happens to the PV loop if the contractility of the heart increases?
What happens to the PV loop if the contractility of the heart increases?
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What does the point labeled "A" represent on the PV loop?
What does the point labeled "A" represent on the PV loop?
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What is represented by the difference in volume between point B and point A?
What is represented by the difference in volume between point B and point A?
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What is the typical range for stroke volume in a healthy adult?
What is the typical range for stroke volume in a healthy adult?
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If the end-diastolic volume (EDV) is 135 mL and the end-systolic volume (ESV) is 65 mL, what is the stroke volume?
If the end-diastolic volume (EDV) is 135 mL and the end-systolic volume (ESV) is 65 mL, what is the stroke volume?
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Which of the following factors can influence the shape of the PV loop?
Which of the following factors can influence the shape of the PV loop?
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What does the portion of the PV loop between points B and C represent?
What does the portion of the PV loop between points B and C represent?
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Flashcards
SA Node
SA Node
The natural pacemaker of the heart that initiates electrical signals.
Cardiac Cycle
Cardiac Cycle
The sequence of events in one heartbeat, including diastole and systole.
Diastole
Diastole
The phase when ventricles are relaxed and fill with blood.
Systole
Systole
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Atrial Systole
Atrial Systole
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Isovolumic Ventricular Relaxation
Isovolumic Ventricular Relaxation
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Pressure Gradients
Pressure Gradients
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Mechanics of the Cardiac Cycle
Mechanics of the Cardiac Cycle
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End-diastolic Volume
End-diastolic Volume
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First Heart Sound (S1)
First Heart Sound (S1)
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Second Heart Sound (S2)
Second Heart Sound (S2)
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Auscultation
Auscultation
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End-systolic Volume
End-systolic Volume
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Pressure Volume Loop
Pressure Volume Loop
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End-Diastolic Volume (EDV)
End-Diastolic Volume (EDV)
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End-Systolic Volume (ESV)
End-Systolic Volume (ESV)
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Isovolumetric Contraction
Isovolumetric Contraction
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Blood Ejection Phase
Blood Ejection Phase
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Stroke Volume
Stroke Volume
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Isovolumetric Relaxation
Isovolumetric Relaxation
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Ventricular Filling
Ventricular Filling
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Pressure Rise in Ventricles
Pressure Rise in Ventricles
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Phase A in PV Loop
Phase A in PV Loop
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Phase D in PV Loop
Phase D in PV Loop
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Ventricular Pressure
Ventricular Pressure
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Ventricular Volume
Ventricular Volume
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Pressure-Volume Relationships
Pressure-Volume Relationships
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Cardiac Cycle Phases
Cardiac Cycle Phases
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Isovolumic Ventricular Contraction
Isovolumic Ventricular Contraction
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Ventricular Ejection
Ventricular Ejection
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Semilunar Valves
Semilunar Valves
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Dicrotic Notch
Dicrotic Notch
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Ventricular Diastole
Ventricular Diastole
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QRS Complex
QRS Complex
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Left Ventricular Volume
Left Ventricular Volume
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Atrial Diastole
Atrial Diastole
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S1 and S2 Heart Sounds
S1 and S2 Heart Sounds
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Wiggers Diagram
Wiggers Diagram
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Early Ventricular Diastole
Early Ventricular Diastole
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Study Notes
Cardiac Cycle Overview
- The cardiac cycle describes the sequence of events during a heartbeat
- It involves two main phases: diastole (ventricles relax) and systole (ventricles contract)
- Electrical signals initiate contraction and blood movement
- Electrical signals originate in the SA node, propagate through the heart, and can be regulated
- Contractile cells convert electrical signals to generate force and pump blood
- This process requires coordinated electrical and contractile mechanisms
- Cardiac function can be assessed by monitoring electrical signals and sounds
Mechanical Events of the Cardiac Cycle
- Late diastole: Both heart chambers relax, ventricles fill passively
- Atrial systole: Atrial contraction forces additional blood into ventricles
- Isovolumic ventricular contraction: First phase of ventricular contraction; AV valves close but semilunar valves are not yet open
- Ventricular ejection: Ventricular pressure exceeds arterial pressure, semilunar valves open and blood is ejected
- Isovolumic ventricular relaxation: As ventricles relax, pressure falls, blood flows back, and semilunar valves close
- These events are cyclical, and there are specific pressure and volume changes associated with each phase.
Heart Sounds
- First heart sound ("lub"): Vibrations following closure of AV valves
- Second heart sound ("dup"): Vibrations created by closing of semilunar valves
Wiggers Diagram
- The diagram visually illustrates the relationship between electrical activity and pressure/volume changes during the cardiac cycle
- It shows how events like mitral valve closure, aortic valve opening, and end diastolic volume relate to different stages of the cycle
Pressure-Volume Loops
- These loops graphically represent the relationship between left ventricular pressure and volume during the cardiac cycle
- Different phases of the cycle (e.g., isovolumetric contraction, ejection, isovolumetric relaxation) are shown as distinct parts of the loop
- Critical values include:
- End-diastolic volume (EDV)
- End-systolic volume (ESV)
- Stroke volume
- These loops display how atrial filling pressure and aortic pressure affect the filling and ejection cycle.
Further Applications of Cardiac Cycle Knowledge
- Understanding normal valve function is important
- Irregularities in the valve operation, such as leakage, can be diagnosed using this knowledge
- Techniques for diagnosing these irregularities are important clinical applications of the cardiac cycle mechanisms.
Key Terms
- Diastole: Relaxation phase of the ventricles
- Systole: Contraction phase of the ventricles
- SA node: Sinoatrial node, the heart's pacemaker
- AV valves: Atrioventricular valves (tricuspid and mitral)
- Semilunar valves: Pulmonary and aortic valves
- EDV: End-diastolic volume
- ESV: End-systolic volume
- Stroke volume: Volume of blood ejected per beat
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Description
This quiz explores the cardiac cycle, outlining the phases of diastole and systole. It emphasizes the electrical signals and mechanical events that govern heart function. Understanding these processes is crucial for assessing cardiac health.