2A Flashcards
What is systole?
period of contraction and emptying.
atrial systole and ventricular systole
What is diastole?
relaxation and filling.
atrial diastole and ventricular diastole
What is SV?
quantity of blood pumped out of either ventricle per beat.
At rest - 70mL/beat; maximum - 120 mL/beat
What is HR?
number of times the heart beats per minute
At rest - 72 beats/minute; maximum - 230 beats/minute
What is CO?
quantity of blood pumped by either ventricle per minute
At rest - 5L/minute; maximum - 20-25L/min
What is the relationship between CO, HR, and SV?
HR x SV = CO
What is venous return (VR)?
quantity of blood returned to heart per minute
Normally VR equals CO
What is EDV?
Quantity of blood remaining in either ventricle at the end of ventricular diastole
average is around 130 mL
What is End systolic volume (ESV)?
Quantity of blood remaining in either ventricle at the end of ventricular systole
What is the end of isovolumetric ventricular relaxation?
When left atrial pressure (LAP) exceeds left ventricular pressure (LVP). Ventricular filling ensues
What is ventricular filling?
Three distinct phases of diastole:
- rapid passive filling
- slow passive filling (diastasis)
- Atrial systole
What is rapid passive filling?
The third heart sound.
It is passive because no muscle contraction occurs
What is atrial systole?
A sudden increase in ventricular filling as it nears its capacity. The atrium contracts to top off the ventricle.
Starts during the P wave on the ECG. Goes from P to Q and R - depolarizing. Depolarizing means contraction. Adds about 10 to 15% of total ventricular volume
What happens after atrial systole?
LVP>LAP and the mitral valve closes producing the first heart sound. The volume of blood in left ventricle is at its capacity - the EDV
What happens to the ECG when the mitral valve closes?
You get the QRS depolarization (the dip after the tallest rise) right before the isovolumetric contraction
What is Isovolumetric ventricular contraction (IVC)?
Ventricles contract and LV pressure rises steadily, however NO ejection of blood occurs - as LV volume remains constant. Pressure not yet greater than aortic pressure
What is rapid ventricular ejection?
The LV develops enough pressure such that LVP exceeds aortic pressure.
The aortic semilunar valve opens and blood is ejected. LVP and Aortic pressure both keep rising
What is - entering back into isovolumetric ventricular relaxation?
Once blood is ejected - LVP falls below aortic pressure and the aortic semilunar valve closes - second hear sound.
What happens to aortic pressure during - entering back into isovolumetric ventricular relaxation - phase?
The aortic pressure also falls as blood runs off to arteries
When is the T wave produced on the ECG?
During the - entering back into isovolumetric ventricular relaxation - phase. The second heart sound “dub” happens during the T wave
What is Isovolumetric ventricular relaxation?
All four chambers of the heart are relaxed and all of its valves are closed.
Ventricular volume is constant, but pressure is decreasing (while atrial pressure will increase).
Left atrium is refilling with blood that has returned to it via the pulmonary veins. Atrial pressure is rising
What is the dichrotic notch?
Closure of the aortic valve causes a brief rise in aortic pressure as backflowing blood rebounds off the closed valve cusps
