Our example tells us that the opening and closing of heart valves is due to the relative pressure in the ventricles compared to the atria and the arteries. We want to use our knowledge of heart anatomy to complete the following table. In this table, we see the relative pressure between two different places in the heart. Then, we want to know which valve is going to be affected by that relative pressure. Is the valve open or closed, and is the ventricle in systole or diastole? Alright.
So far, we've just talked about sort of pressure changes generally. Now we're going to go through all this and compare it to the heart. But even right now, you should know your heart anatomy decently well, and just knowing these pressure changes, you should be able to figure out what's going on here. So let's give it a try. We're going to start with the aorta. It says the pressure in the aorta is greater than the pressure in the left ventricle.
Well, here's our aorta, and here's our left ventricle. So the first question is, what's the valve that's affected? What valve is between the aorta and the left ventricle? Well, I'm going to say that that's the left semilunar valve. I'm just going to write abbreviations there just to save space.
Or slash. We can also call that the aortic valve or the aortic semilunar valve. Alright. So the left semilunar valve or the aortic semilunar valve. And so if the pressure is greater in the aorta than the left ventricle, is that valve going to be open or closed?
Well, if the pressure is greater up here, that means that it's sort of pushing backwards on there, and that's the opposite way that we want blood to flow. Right? Those semilunar valves, those are the outdoors for that ventricle. So if the blood's trying to sort of go in the opposite direction than it's supposed to go, that's going to push that valve closed. So this means that the valve is going to be closed.
And next, we want to know is the ventricle going to be in systole or diastole? Remember, we have the systole squeeze, that's a contraction. Diastole, the pressure drops during relaxation. Now just to be really clear, for all of these, technically it could be in either one, and it will be in either one during some times during the heart cycle. However, for most of the time, generally, we can say systole or diastole for this.
So if the pressure in the left ventricle is lower than the pressure in the aorta, would you expect that that heart is in systole or diastole? Well, if the pressure is low in the ventricle, that means that it is likely in diastole. That pressure is dropped. The pressure has fallen because the ventricle is relaxing. Alright.
Next up, we have the pressure in the right atrium is greater than the pressure in the right ventricle. So here's our right atrium. Here's our right ventricle. So first off, what i
