Lecture 3: The Heart pt.2 Flashcards
True or False?
The Ventricular Pressure Volume Loop involves time.
FALSE
In what direction does the Ventricular Pressure Volume Loop go in?
Counter Clockwise
In the corners of the loop, what does it show?
Something happening to the valves
Volume increases and all of a sudden, the volume stops changing and the pressure goes up. Why did the pressure go up?
It means either pressure in the atrium and ventricle are equal OR the atrium and the ventricle are separated because THE MITRAL VALVE IS CLOSED.
Why is the mitral valve closed?
The pressure in the ventricle became higher than the pressure in the atrium.
As pressure goes up, we have another change. The volume of blood in the left ventricle starts to drop. Where’s the blood going?
The LV to the Aorta
How does blood go from the LV to the Aorta? What has to happen?
The Aortic Valve has to open. The volume in the ventricles dropping, pressure is dropping,
What do you know if the volume isn’t changing anymore?
It could be that the pressure in the ventricle and aorta are equal again or the aorta and the ventricle are separated from each other.
As the volume in the LV stops dropping, what happens?
The aortic valve closes
As the volume of blood in the LV ventricle increases again, what happened?
The mitral valve opens
What is the pressure phase when the mitral valve closes to the aortic valve opens?
Isovolumetric contraction
As pressure goes up in the LV, but no more blood is coming in. What happened to cause the pressure to go up?
Contracting
In an isovolemtric contraction, what happens to the ventricles?
The ventricle is isolated because the valves on both ends are closed. The pressure is high enough to close the mitral valve but NOT high enough to open the aortic valve yet.
What phase is between when the aortic valve opens to the aortic valve closes?
Ejection Phase
What happens in the Ejection Phase?
The volume of blood in the ventricle is decreasing.It is being squeezed out to the aorta.
What is the reason the pressure goes first?
Ventricular contraction is so powerful and fast, the ventricle is getting smaller faster than the blood is leaving.
When there’s no change in volume and the pressure drops, what phase occurs?
Isovolumetric Relaxation
What occurs in the Isovolumetric Relaxation phase?
Both the valves are closed and the volume of blood in the LV isn’t changing because the ventricle is relaxing. The box the blood is in is getting bigger and let’s the pressure drop.
If the AV valve is open, what happens to the volume?
the volume has to go up in a normal heart
If the Semilunar valve is open, what happens to the volume?
the volume has to go down
The only way to have the volume not change is…
to have both valves closed.
If the volume is changing, what does this mean?
one of the valves has to be open.
What is the phase when the mitral valve opens to when the mitral valve closes?
Ventricular Filling
What happens to the volume and the pressure in Ventricular Filling?
The volume increases and the pressure drops a little bit and gradually increases.
The first 2/3 of Ventricular Filling is when what occurs?
Rapid Fill
What happens during Rapid Fill?
The blood goes into the ventricle fast.
There’s not much blood in ventricle at all and the blood come racing through the LA from the Pulmonary Veins.
What comes after Rapid Fill?
Diastasis
What happens during Diastasis?
Still filling, but slower
What is the last piece that is the end of Diastasis to when mitral valve closes?
Atrial Systole
What happens during Atrial Systole?
The last volume of blood to fill the ventricle
In a normal healthy heart, the sounds are made by valves and the valves only make sounds when…
they close
Where does Heart Sound (S1) occur?
When the mitral valve closes
Where does Heart Sound (S2) occur?
Is caused by the aortic valve closing
There’s a period of time in a healthy human, when there is a normal S3. When is this?
In early infancy
Where does Heart Sound (S3) occur?
At the end of rapid fill
How will you decide if the pressure is higher in the atrium or the ventricle? (Isovolumetric Contraction)
You look at the valve between the LA and the LV. If the valve is closed, the pressure is higher in the chamber after the valve than in the chamber before the valve.
If the valves closed, what happens to the pressure in the LV?
P LV > P LA
During ejection, is the mitral valve open or closed?
Closed
What proves that the valve is closed?
The pressure increases and blood is not coming into the ventricle from the atrium. Blood IS NOT moving from the atria to the ventricle.
In ejection, what happens to the pressure in valves?
P LV > P LA
What happens if blood isn’t coming into the ventricle from the LA, what do you know?
During isovolumetric relaxation, the volume of blood in a ventricle isn’t changing. It tells you blood isn’t coming from the atrium to the ventricle.
When does blood NOT go from the atrium to the ventricle?
When the valve is closed
Why would the mitral valve be closed?
The pressure after the valve is greater than the pressure in the atrium.
In Isovolumetric Relaxation, what happens to the pressure?
P LV is STILL > PLA
In Ventricular Filling, the volume of blood in the ventricle is UP. Where’s the blood coming from?
The LA
So if blood is coming from the LA into the LV. What do you know about the pressure in the LA compared to the LV?
The pressure has to be higher in the atrium because blood goes from the place where the pressure is higher to the place where the pressure is lower.
Ventricular Filling is the only phase where LA > LV pressure. Why is that?
Because it is the only phase where blood is moving from the atrium into the ventricle.
During Isovolumetric Contraction, is the blood moving out of the ventricles in the Aorta?
No, if blood is moving, the chamber that the blood is moving from has higher pressure than the chamber it’s going into.
In Isovolumetric Contraction, what happens to the pressure of the Aorta and LV?
P Aorta > P LV
Because the blood isn’t going from the LV into the Aorta
In Ejection, is blood going from the ventricle into the Aorta? If so, which pressure is higher, LV or the Aorta?
Yes, the P LV > P Aorta
During Isovolumetric relaxation, is blood moving from the ventricle to the aorta?
No, the volume isn’t changing. P Aorta > P LV
You need to have 100 mm of pressure to open the aortic valve, that’s the minimum pressure that will open it. Any pressure below that means…
it’s not open
In Ventricular Filling, is blood moving from the ventricle to the aorta?
No. The P Aorta > P LV
The only cardiac cycle where the P LV > P Aorta and the only phase where the blood goes from the LV into the Aorta.
Ejection Phase
There is only one phase in the cardiac cycle where the pressure in the LA is higher than the pressure in the LV where blood goes from the atrium into the ventricle.
Ventricular Filliing
Ventricular Systole takes up ________ of the cardiac cycle.
1/3
Diastole takes up the other ________ of the cardiac cycle.
2/3
How does the pressure in the left ventricle get to be higher than the pressure in the left atrium?
The ventricles start to contract
Where does Ventricular Systole start?
starts a little before the mitral valve closes
______ raises pressure enough to close the valve.
Systole
What is the start and end of Ventriular Systole?
Starts BEFORE mitral valve closes and end BEFORE aortic valve closes. Because in order for pressure to drop below aortic pressure, the ventricles have to start relaxing.
Where does Diastole start and end?
Starts AFTER aortic valve closes, and ends BEFORE mitral valve closes.
