Trace one drop of blood from the time it enters the right atrium until it enters the left atrium. What is this circuit called?

Video transcript

Hi, everybody. Let's look at our next question. A patient receives a venous injection of a radioactive sodium isotope. Which route should this radioactive sodium take? In order to reach the kidney? And we have four different answer choices with different routes. So I think rather than read all of these out loud first, we'll talk through the route. It would go using our knowledge of the circulatory system. And then we'll use that to evaluate our four answer choices that we will read through. So we think of the radioactive isotope being injected into a vein. It's a venous injection. So we'll start with vein and then I'm using little arrows as our answer choices do to indicate where it's going. All veins eventually drain into the vena cava. And that will empty into the heart on me. We put right side of the heart from there, it will go through the pulmonary artery to the lungs. Since we inject it into a vein, it has to go through the lungs first before it makes its way to any other part of the body. So out of the lungs to the pulmonary vein that will take it back to the left side of the heart. So I've written heart and then in parentheses, left out of the heart, it gets pumped into the aorta and then we'll go into the renal arteries and then can filter out into the kidney. So we've got a long pathway because since we injected into a vein, it has to circulate all the way through the heart, through the lungs, back through the heart before it can get to the kidney. So let's look at our answer choices and compare it to the pathway that we have walked through. Here. Choice. A says viva heart, pulmonary arteries, lungs, pulmonary veins, heart aorta renal arteries, kidney. So right away in choice, A, we have one that matches the pathway that we figured is correct. We'll just look at our other entry choices to be thorough. Choice. B says Vena cava aorta renal arteries, kidney, well, this not only skips the lungs, it skips the heart altogether. Um So that's why choice B is incorrect. Choi says veva heart coronary arteries, heart aorta renal arteries, and then kidney and this skips the lungs altogether. And we know that not through the coronary artery, but it will go out through the pulmonary artery and circulate through the lungs. So that's why choice C is incorrect. Then choice D says Veneva heart, pulmonary arteries, lungs, coronary veins, heart aorta renal arteries, kidney here. What we have wrong that is that it's not the coronary veins that take blood from the lungs to the heart, but the pulmonary be. So that's why choice D is incorrect. So again, our answer choice here of the route a venous injection of a radio radioactive sodium isotope will take to get the kidney reach the kidney is choice A and I won't read that all out again because we've now read it through two times. But choice A is our correct answer here. See you in the next video.