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77 Cards in this Set

  • Front
  • Back
What happens to the distribution of blood volume during inspiration?
It goes into the most compliant areas like the pulmonary vessels and the right side of the heart.
How do you figure out which valve closes first in normal inspiration?
Think about it like this: the right side has more blood than usual and the left side has less because it is held in the lungs.

With less to eject, the left side starts off with less pressure and the A2 closes earlier than the P2. M1 will close earlier than T1 because there will be less pressure in the left atrium.
What is the general rule for valve splitting order?
In inspiration, the left will close earlier than the right simply because it is working with less blood and pressure.
What is the quietest heart sound? What is it caused by?
S4 by atrial contraction during end diastole. Like a little extra squirt into the ventricles.
What is S3 and what side of the stethescope should you use to listen to it? Why?
It is the sound in middle diastole that is due to the sloshing of blood in both ventricles hitting each other. Listen with the bell side because it is low frequency.
What is the left lateral decubitus position?
Just mean lying on your left side. It is good for pressing the apex closer to the surface.
In which people is S3 normal?
youth, some trained athletes, and sometimes in pregnancy
Do parasympathetic fibers have any effect on vessel constriction? WHat do they have control over in the cardiorenal system?
No. they have control only of heart rate, conduction velocity, and contractilty in the atria.
Why is there no increase in pulmonary wedge pressure in pulmonary hypertension?
Because this is due to a backup in the right, due to constriction of arteries. pulmonary wedge pressure measures left atrial pressure and comes after the pulmonary arteries.
In words, describe LaPlace's Law.
The bigger a vessel/ventricle is, the more force or tension it needs to exert in order to withstand the same fluid load.
Why does LaPlace's law happen?
It's pure physics, you are resisting a perpendicular force exerted by a liquid in either a cylinder or a sphere. The wider the circle, the more oppositional force you need to exert in order to get the same sin component.
http://hyperphysics.phy-astr.gsu.edu/hbase/ptens.html#lap2
Equation for Laplace's law of a vessel vs a sphere.
vessel- Tension = Pressure x Radius
sphere (ventricle)- Tension = PR/2
Why do you divide by 2 for a sphere?
If you think about it, there are more contact points in the walls to support the tension so increasing the pressure will have less of an effect.
How can you visualize LaPlace's law?
A weight (pressure being exerted) being held up by two strings connected to the circumference of a circle.
How does La Place's law play into emphysema?
You have...
increased radius (alvelolar wall destruction and chest expansion)
about the same tension (walls are weaker, but held open by chest)
and much less collapsing pressure (no surfactant to close)
Why is it so difficult for me to visualize LaPlace's law in emphysema?
there are a TON of components coming into play and it's hard to isolate each one and judge how much weight each one has. Just chill and remember that it's harder to close because the alveoli are more stretched out and don't have surface tension to pull them shut.
Why may the fourth heart sound be heard during atrial contraction?
If ventricular compliance is decreased and the ventricles are tight and unaccomodating to more blood. This happens in wall thickening hypertrophy or overfilling.
What are the components of the Starling forces? What do they determine?
Oncotic and hydrostatic pressure to determine which way fluid will flow.
How should you explain physiology to a patient?
Don't decribe all the forces, just decribe the forces that end up winning out and driving the outcome.
What is the best measurement indicator of stroke volume?
pulse pressure
How does pulmonary edema effect oxygen diffusion? (where does the fluid go)
the fluid first goes into the interstitium where it increases diffusing distance. the lack of oxygen causes hypoxic vasconstriction and hypoxia.
What is dyspnea?
The sensation of difficult breathing
What causes dyspnea in CHF? (3)
1. decreased O2 from increased diffusion distance
2. cardiac asthma from fluid going up to the bronchi and stimulating mucus production
3. Accumulation of edema leads to decreased compliance and increased work to breath
What does furosemide (lasix) do?
It prevents Na from being resorbed and so more Na and water are excreted.
Should you give furosemide to a pt with CHF and hypotension?
Yes. The most important thing is to get rid of their pulmonary edema.
What is propanolol?
A general beta blocker
What are some brands of propanolol?
atenolol.
What produces the sound of a murmur?
Blood turbulence, which can be either due to regurgitation or stenosis.
What may cause a diminished A2 heard on inspiration? Why?
Aortic stenosis because the valves are relatively fixed and small.
What is the normal difference between left ventricular and aortic pressure during systole?
close to 0 because the left ventricle had to get even with the aortic pressure befor ejecting
When may the difference between left and aortic pressure increase to more than 0?
When there is resistance in between.

During aortic stenosis because you need that extra pressure to hold the aortic valves open. The pressure is lost through that struggle.
What is wall stress? How would you visualize it in the left ventricle?
It is the tension that is pulling on the string attached to the ball to counter the pressure exerted by it. You can visualize it as arrows going concetrically around the ventricle wall that is pulling it apart.
How is wall stress countered by increased sarcomeres?
More sarcomeres means more desmosomes, which are the things that exert the counter force to wall stress.
What is LaPlace's law for the heart? Equation and then words.
Wall Stress (tension) = Pressure x Radius / 2 x wall thickness

The stress on the wall increases with either radius or increased pressure. Increasing wall thickness will counter wall stress.
WHy would syncope happen in a person with aortic stenosis who is exercising?
They left ventricle is already working really hard at rest to maintain a normal CO. In exercise, even more CO is demanded and TPR goes down too. The heart is unable to work harder to keep up the arterial pressure and syncope happens.
When may you have atrial hypertrophy?
After you have large pressure in the ventricles chronically. This can come from any kind of valvular stenosis or a large afterload which will cause ventricular hypertrophy first.
What does the PR interval include?
it's from the beginning of atrial depolarization to the beginning of ventricular depolarization. It includes the P wave and the PR segment.
How long is the PR interval usually and where is most of this time spent?
.12-.2 seconds and it is mostly throught the AV node.
What is always the cause of syncope?
decreased arterial pressure
What does atropine do?
It is an antagonist of the parasympathetic nervous system.
WHy is heart failure rising over the years?
Because we are getting so good at helping people survive MIs. They then live with damaged ventricles and are predisposed to heart failure.
What is the leading cause of death in the US?
Cardiovascular disease inclusing stroke
In what direction does the ventricle contract? How does it do that?
In all directions in a twisting motion and it does this by having each sheet of cardiac muscle having fibers in a slightly different angle.
Why is the twiting motion advantageous?
It helps get more blood out like a wringing motion and also starts from the bottom like a tube of toothpaste efficiently squeezed.
How is pulmonary wedge pressure the same as left atrial pressure?
You cutt off flow from the artery by inflating the baloon tip of the catheter. Then all you get is back flow from the left atrium.
Why not just take the left atrial pressure directly?
It's hard to get a cathether in there.
Where do the coronary arteries come off of?
At the beginning of the aorta (they are the first ones). The two of them originate from within the semilunar cusps of the aortic valve.
Where does coronary blood drain?
The blood collects in the coronary sinus (a large vein under the pulmonary trunk) and drains directly into the right atria.
Why does ACh stimulation of a blood vessel with damaged endothelial cells not work?
Because the endothelial cells are not there to release NO to dilate the vessels.
How do endothelial cells prevent blood clotting from happening?
It shield the collagen containing connective tissue and basement membrane from getting in contact with clotting factors like Hageman that are activated by it.
Which valve is more anterior, the pulmonary or the aortic? Mneminic?
The aortic.

Aortic = Anterior
How do the aorta and pulmonary trunk cross?
The aorta passes in front on the right pulmonary artery branch and then behind on the left. However, the pulmonary trunk passes in front of the aorta, but this is concealed by the heart muscle.
What type of collagen is in the basement membrane right beneath the endothelial cells?
Type IV
What is the lamina propria?
a thin layer of loose connective tissue, or dense irregular connective tissue, which lies beneath the epithelium
What is the mucosa?
The combination of the epithelium and the lamina propria.
What is a mechanical way that endothelial cells secrete NO?
Sheer stress from HTN
Are they always secreting NO?
Yes, they keep a basal relaxation and if you block NO production, your BP would go up 10-15mmHg.
Can the endothelial cells also produce vasoconstrictors? Which ones?
Yes. Angiotensin II, Endothelin, PGI2, and EDCF1 and 2.
Explain the action of angiotensin II.
It increases aldosterone production of the adrenal cortex and raises blood volume and also is a vasoconstrictor everywhere except the lungs.
How do the endothelial cells make angiotensin II?
They take angiotensin I from the plasma and use their ACE enzyme to convert it. Not nearly as powerful as the lungs though.
Who else has ACE powers?
The kidneys.
WHat is endothelial dysfunction and why is it dangerous?
It is when the endothelial cells can't make their products as well. This includes NO, vasoconstrictors, and ANgiotensin II. It is dangerous because it can lead to a ton of pathologies including HTN and atherosclerosis.
What causes endothelial dysfunction?
oxidative stress
What causes oxidative stress on the endothelium? (5)
Inflammation from rips from HTN, oxidized LDL-C, diabetes, smoking, and hypoxemia.
What are three treatments to fix atherosclerotic narrowing of the coronary arteries before or after thrombolytic treatment?
1. angioplasty
2. stents
3. CABG
Describe angioplasty.
You push a balloon catheter into the vessel and inflate it to make more space.
What are 2 downsides to angioplasty?
The reocclusion rate is pretty high (vessels are elastic after all) and there may be damage to the already hardened arteries during expansion.
Explain stenting and it's downside.
You leave a stent that is like a mesh that keeps the artery open after angioplasty. However, this stent can be a place for thrombi to form.
WHat is the most popular method? Which method is losing popularity?
Stenting has been booming. CABG has been declining.
Where does pressure of the blood drop precipitously? Why?
At the arterioles because they have resistance and use up power. (like a voltage drop)
is velocity higher in the capillaries or the venules/veins? Why?
The venules/veins because they have a much lower cross sectional area and speed the blood back up.
How much of the blood volume is in the venous side at any given time at rest?
80%
What is blood flow/minute?
5L/min
Which organs get the highest proportion of blood at rest? (top 3)
1. intestinal system (28%)
2. kidneys (25%)
3. muscle (20%)
How much of the blood does your brain get?
15%
How much of the blood goes to the skeletal muscle during moderate exercise?
80%!
How much of the blood goes to the brain during moderate exercise? WHat does this tell me about pike's peak?
5%

This tells me that I has making my cerebral hypoxia 3 times worse on the treadmill and that's probably why I was blacking out.