A&P CV2 Loops Flashcards
Ventricular pressure -volume loops demonstrate the changes in
Intraventricular volume and pressure during normal cardiac cycle
How many steps are in the ventricular loop cycle?
4
Isovolumetric Contraction Step 1 (B-> C) Happens just after
the QRS
Isovolumetric Contraction is the period between _____ and _____.
Mitral valve closing and aortic valve opening
Mitral valve closing and aortic valve opening occurs in what phase of loop cycle?
Isovolumetric contraction
What period has the highest O2 consumption?
Isovolumetric contraction
Isovolumetric contraction CYCLE begins
during diastole (at point B)
The left ventricle is filed with blood from teh left atrium (vol = 140ml) during what cycle?
Isovolumetric contraction
During Isovolumetric contraction, what does the ventricular pressure do? why?
Pressure increases b/c the valves are closed and the ventricle is filling.
Isovolumetric contraction follows what law?
Laplace’s Law
Laplace’s Law is (equation)
T=Pr
T=Pr
Laplace’s law
What part of the loop cycle follows Laplace’s Law?
Isovolumetric Contraction (B to C)
What is the ventricular end -diastolic volume?
~ 140ml
Cycle 2 of the ventricular P-Vol Loop is
Ventricular Ejection (C to D) or “emptying”
Ventricular Ejection is what cycle of the P-Vol loop?
cycle 2 (C to D)
Cycle 2, Ventricular Ejection is the period between what opening and closing?
aortic valve opening and closing
at what point (A, B, C, D) does the aortic valve open?
C
The aortic valve opens when pressure in …
the left Ventricle exceeds pressure in the aorta.
When the left Ventricle exceeds pressure in the aorta what happens? Where do we see this on the loop graph?
The aortic valve opens
See at point C
During Cycle 2, Ventricular Ejection blood is ejected into the aorta, and Ventricular Vol does what?
decreases
The volume ejected during cycle 2 from the ventricle is known as the:
Stroke Volume
Stroke volume can be measured on the P-Vol loop graph where?
The WIDTH of the loop
The volume remaining in the left ventricle (at Point A) is:
end-systolic volume
Equation for loop calculation of SV
SV = EDV - ESV
SV = EDV (point B) - ESV (point A)
Equation for loop calculation of EF
EF = SV / EDV
[(point B - point A)/ point B]
Cycle 3 of Ventricular P-Vol Loop is called
Isovolumetric relaxation
Isovolumetric relaxation occurs at what cycle in the loop?
cycle 3 - point D to point A
Isovolumetric relaxation is the period between
aortic valve closing and mitral valve opening.
the period between aortic valve closing and mitral valve opening is known as:
Isovolumetric relaxation (D to A)
What happens at point D?
the ventricle relaxes
Where does the Ventricle relax on the loop? (what point)
D