Pathophysiology

Be_Moore · Oct 24, 2009

1) Think of the valves like doors. If you are opening a door, you have to push the door harder than the air pressure on the other side of the door (as well as harder than the resistance created by the door frame) to open it. If you don't push harder than those resistances, the door won't open. You have to overcome ventricular backpressure to allow the valves to open. This is the type of thing you won't see a whole lot of problems with...what you will see problems is when the valve itself has stenosis, which makes the valve really hard to push open (think of stenosis like the door example above, but instead of just opening the door, now the door is stuck and you have to push a lot harder to get the door to open). The other problem you will see with valves is when they let blood come backwards through them, called regurgitation (like a door that doesn't seal properly, allowing a draft to come through).

2) As with most things, nothing happens in a vacuum. When you build plaque in your arteries, you will build it in all of your arteries. Plaque is kind of like dropping sand into the ocean. The current of the ocean will push it around and around and it will eventually more or less settle, but not all in one place. We tend to notice occluded arteries in the heart more often because a heart attack is more serious than a little occlusion. The other reason that it seems to happen in the coronary arteries moreso than other arteries is because 1) Coronary arteries are under a lot less pressure than other arteries (coronary arteries perfuse the heart during diastole, when the heart is at rest, as opposed to every other artery which perfuses during systole) and 2) Coronary arteries are smaller, like the size of a small drinking straw vs. the size of your finger (like the femoral).