Blood returning to the mammalian heart in a pulmonary vein drains...

Question

Blood returning to the mammalian heart in a pulmonary vein drains first into the
a. left atrium.
b. right atrium.
c. left ventricle.
d. right ventricle.

Accepted Answer

Hi everyone here's our next problem. It says the blank carries deoxygenated blood from the heart to the lungs. And our four choices are pulmonary vein, pulmonary artery, aorta or inferior vena cava. Well the first thing we'll zoom in on here is that we're looking at the pulmonary circulation as we recall, we've got two different circuits the pulmonary circulation between heart and lungs, back and forth and systemic circulation between the heart and the rest of the body. So since we're talking about blood going from heart to lungs, um we want a pulmonary, either vein or artery. So we can go ahead and eliminate choices C. And D. Because they are part of the systemic circulation, not the pulmonary. So now we just have to um think about which way the veins and arteries are going to figure out which one has the deoxygenated blood. Well, we recall that way when we want to think about arteries and veins, we think artery beginning with a means away. It's the little trick to remember that from the heart and therefore veins must carry blood to the heart. And we remember since we're talking about pulmonary circulation um that oxygenation and de oxygenation of artery and vein will be reversed from the way they usually are in the system and the systemic circulation. So in this case carrying blood away from the heart. Well it's carrying but away from the heart but in the pulmonary system away from the heart to the lungs means that is deoxygenated blood. It's coming to the lungs to get oxygen. So the pulmonary artery has the de oxygenated blood. It would be the only artery in the body that has deoxygenated blood and the systemic circulation. All those arteries have oxygenated blood being pumped from the heart to the rest of the body. So choice B will be correct since we're looking for deoxygenated blood going from heart to lungs because the pulmonary vein vein into the heart will have oxygenated blood. It's gotten its oxygen in the lungs and now it's going back to the heart to be distributed. And just to be thorough if we wanted to look again at C. And D. The aorta that's um that they can help us remember. That's that main largest artery in the body carrying blood away from the heart. And so the order the aorta carries oxygenated blood. The inferior vena cava. Along the superior vena cava. The two biggest veins in the body carrying deoxygenated blood back to the heart. So they do have deoxygenated blood but they're not carrying it from the heart to the lungs. So we're looking at again the correct answer. Be pulmonary artery. See you in the next video

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