Mechanical Activity Of The Heart Flashcards
Fluid will move according to __________
Pressure gradients
- high pressure to low pressure
- will flow until pressure is equalized
What does it mean for blood to be non compressible?
Compression will raise pressure without affecting volume
What does it mean that the heart is compliant
Blood filling heart will increase pressure and increase its volume
What are atria primarily for?
Used to fill ventricles
What are the ventricles for
Force generation
Which ventricle is stronger
Left
Purpose of the AV valves?
Prevent backflow into atria
Where is the mitral valve
Between LA and LV
Where is the tricuspid valve?
Between RA and RV
What do the semilunar valves prevent
Backflow into ventricles
Where is the pulmonary semilunar valve?
Between RV and pulmonary artery
Where is the aortic semilunar valve located?
Between LV and aorta
Period of relaxation and filling with blood
Diastole
Diastole: pressure drops, no change in volume
Isovolumic relaxation
What happens during diastole?
- isovolumic relaxation
- rapid filling
- reduced filling
Period of force generation
Systole
Systole: isovolumic contraction
Pressure rises, no volume change
What happens during systole
Isovolumic contraction
Rapid ejection
Reduced ejection
Filling of ventricle in diastole happens as long as what
Left atrial pressure is higher than left ventricular pressure. Mitral valves is opened, aortic valve is closed
When does diastole end
As ventricle begins to contract
On a pressure vs time chart, when does diastole end?
In window A. It’s a small rise in pressure
What is the volume that is left in the left ventricle at the end of diastole called?
End-diastolic volume ((EDV)
What is the pressure of the LV at the end of diastole?
End-diastolic pressure (EDP)
What does end diastolic pressure tell us?
Preload. Amount of stretch before it contracts. Venous return is also preload
On a pressure vs volume graph, where is diastole?
C
What is the beginning of systole
LV begin to contract and mitral valve slams shut
What is the first heart sound
The beginning of systole
-LV begin to contract and mitral valve slams shut
During systole, when can blood escape the left ventricle
Heart rapidly builds pressure but blood cannot escape until it surpasses aortic pressure.
-systemic blood pressure is higher than LV pressure and has to overcome this to move
How fast the LV blood pressure is generated (dp/dt) can be used as a readout of contractility
Isovolumic contraction
-until it generates enough force to move. Has to overcome afterload. Isometric to isotonic
On the pressure vs time graphs, where is systole?
In column B-D
Sharp incline
On a pressure vs volume graph, where is systole?
C-D
On the pressure vs volume graph, where does the mitral valve close?
C
On the pressure vs volume graph, where does the aortic valve open?
D
What happens when LV pressure surpasses aortic pressure?
Aortic valve opens, blood is ejected into circulation
Rapid ejection
Why does flow through aorta continue even when pressure gradient drops?
Due to the dispensable it’s of aorta.
-reduced ejection
When do aortic valves close?
Once flow slows enough
Ventricles begin to relax
Atria fill throughout what
Ventricular systole
What is the second heart sound
Once flow slows enough, aortic valves close and ventricles relax
What is the volume left at the end of systole
End systolic volume (ESV)
Volume left ventricle after its finished contracting
Where is rapid ejection shown on the pressure vs time graph?
C
Where is rapid ejection show on the pressure vs volume
D-E
Where is reduced ejection on the time vs pressure graph?
D
Where is the reduced ejection on the pressure vs volume graph
E-F
When HR goes up, which shortens, diastole or systole?
Diastole
Between diastole and systole, which is longer?
Diastole
Heart rapidly relaxes with no volume change
Isovolumic relaxation
Where on the pressure vs time graph is isometric relaxation
E
When does the mitral valve open?
Once left atrial pressure is greater than left ventricle pressure
-rapid filling of ventricle
What happens to the ventricle as it fills?
Filling slows as ventricle fills
- increasing volume slowly stretches heart to increase pressure
- reduced filling
Where on the pressure vs volume graph, where is isometric relaxation
F-A
How many heart sounds are there?
4
What is the 1st heart sound?
Mitral valve closure
When do you hear the first heart sound?
Initiation of systole
How many heart sounds do you NORMALLY hear?
2
What is the second heart sound?
Aortic valve closing
When do you hear the second heart sound
End of systole, start of diastole
When does the 3rd heart sound occur?
Blood rushing into ventricles.
Early in diastole
Changes in which ventricles fill with blood. Rapid influx of blood in ventricles
Who can you sometimes hear the 3rd heart sound in and what does it indicate?
-small children and highly trained athletes. NORMAL
If you hear this heart sound in anyone else, it is pathologic
What is the 4th heart sound?
Filling a stiff ventricle
Late in diastole
What is the 4th heart sound associated with?
Pathology, usually heart failure.
What is the lub, in lub-dub
1st heart sound, mitral valve closing
What is the dub, in the lub dub
Aortic valve closing
Why is blood flow unidirectional
Because of valves
What prevents backflow into the atria
AV valves (mitral, tricuspid)
What prevents backflow into ventricles
Semilunar valves (pulmonary and aortic valves)
What is the difference between volume at the end diastole and end systole
Stroke volume (SV)
SV is equal to
EDV-ESV
What is a normal SV
95m/s
What is the total amount of blood ejected during one beat
Stroke volume
Sounds that arise from valvular issues
Murmurs
These types of murmurs allow backwards flow
Incompetent
This type of murmurs the valves don’t fully open
Stenotic
These types of murmurs are heard during systole
Systolic murmurs
These types of murmurs are heard during diastole
Diastolic murmurs
These types of murmurs are heard all through the cardiac cylce
Continuous murmur
What kind of murmurs arise from valve pathology
Systolic and diastolic murmurs
What kind of murmurs arise from an atomic malformation
Continuous murmurs
What kind of murmur has the loudest sound during systole
Systolic murmur: stenotic aortic murmur
What kind of systolic murmur has least amount of sound in systole
Incompetent (mitral)
What murmur is heard the loudest during diastole?
Aortic incompetent
Which murmur is heard the least in diastole
Mitral (stenotic)
What kind of murmurs result from holes in heart
Continuous
During which stage of the cardiac cycle is ventricular pressure falling and all valves are closed?
Isovolumic relaxation
What would happen to stroke volume if ESV got larger
Lower
An incompetent mitral valve would allow blood to flow from the
LV to the LA
