Section 2A Flashcards
What is Diastole
Period of relaxation and filling
-Atrial diastole and Ventricular diastole
What is Systole
Period of contraction and emptying
-Atrial systole and Ventricular systole
What is Stroke Volume
Quantity of blood pumped out of either ventricle per beat
What is the stroke volume at rest and its maximum
At rest: 70 ml/beat
Maximum: 120 ml/beat
Define Heart rate
Number of times the heart beats per minute
What is the heart rate at rest and at its maximum?
At rest: 72 beats/min
Maximum: 230 beats/min
What is Cardiac Output
Quantity of blood pumped by either ventricle per minute
Cardiac Output at rest and at its maximum?
At rest: 5 L/min
Maximum: 20-25 L/min
What equations explains the relationship between CO, HR, and SV?
HR x SV = CO
Define Venous Return
Quantity of blood returned to the heart per minute
Normally, the venous return equals what?
The cardiac output
Define End Diastolic Volume (EDV)
Quantity of blood remaining in either ventricle at the end of the ventricular diastole
What is the average value of EDV?
130 ml
Define End Systolic Volume
Quantity of blood remaining in either ventricle at the end of ventricular systole
Equation for Ejection Fraction
SV/EDV
All 4 chambers of the heart are relaxed and all valves are closed
Isovolumetric ventricular relaxation
What 3 events are occurring during Isovolumetric Ventricular relaxation
- All chambers of heart are relaxed and valves are closed
- Ventricular volume is constant and pressure is decreasing
- Left atrium is filling with blood that has returned from the pulmonary veins; left atrial pressure is rising
2 events of End of Isovolumetric ventricular relaxation
- Left atrial pressure (LAP) exceeds Left ventricular pressure (LVP), resulting in opening of the Mitral valve
- Ventricular filling ensues
Ventricular filling has what three phases?
- Rapid Passive Filling
- Slow Passive Filling
- Atrial Systole
Rapid Passive Filling
- Blood flows quickly through the mitral valve and into the relaxed ventricle
- Ventricle volume increasing
- Third heart sound produced
- No muscle contraction
What occurs during Slow Passive Filling (Diastasis)
- Blood flows slowly through mitral valve and into the relaxed ventricle
- Ventricle volume increases
- No muscle contractions
What occurs during the 3rd phase of filling called the Atrial Systole
- Atrium are depolarized and contract producing a small contribution to ventricular volume
What occurs immediately after Atrial Systole
- LVP>LAP which causes mitral valve to shut
- First heart sound produced
- Volume in the left ventricle is the End Diastolic Volume
What occurs during Isovolumetric Ventricular Contraction phase
- Left ventricle is depolarized and contracts
- LVP rises steadily
- No Ejection of blood because ventricular volume stays constant
