If a molecule of CO₂ released into the blood in your left toe is exhaled from your nose, it must pass through all of the following except
a. The pulmonary vein.
b. The trachea.
c. The right atrium.
d. The right ventricle.

Question

If a molecule of CO₂ released into the blood in your left toe is exhaled from your nose, it must pass through all of the following except

a. The pulmonary vein.

b. The trachea.

c. The right atrium.

d. The right ventricle.

Accepted Answer

Welcome back. Let's look at our next problem. It says deoxygenated blood will be present and all of the following except so that except reminds us we'll be looking for something with oxygenated blood. So, our choices here are pulmonary artery, vena cava, pulmonary vein and hepatic vein. So it can be very confusing, keeping track of the two um parts of the circulatory system, the circulation through the body, the systemic circulation and the pulmonary circulation through the lungs. Um and then keeping straight veins and arteries. So I like to draw myself a little diagram very simplistic just to keep that straight in my head if I'm working on problems like this. So I'm gonna draw just very simplistic little heart and some funny looking little lungs over here and then I'm just gonna write body. If I could write a stick figure. Now, as we recall from our content videos, um we have the heart pumping oxygenated blood throughout the body. So I'm going to label that oxygen oxy oxygenated and then deoxygenated blood gets pumped back to the heart. So we'll label that deoxygenated. Then when this deoxygenated blood gets to the heart, it gets pumped to the lungs to pick up oxygen again. So we know this heart to lungs that's deoxygenated and after getting oxygen in the lungs that blood gets pumped back to the heart for distribution to the body. So that simplistic little diagram just kind of helps helps me keep that straight now. We want to look at arteries and veins and that has to do with whether the blood is being carried away from the heart or to the heart. And a convenient little way to remember that is arteries beginning with a mean away eh, so veins carry blood toward the heart. Right heart. Remember, so armed with those two things, let's work through our choices. Choice A says pulmonary artery, pulmonary lungs. So this would be the artery between the lungs and the heart. Arteries mean away from the heart. So for saying away from the heart to the lungs. Well, we see that is the oxygenated blood. So we want the exception. So that is not the correct answer. We eliminate choice A choice B says vena cava or the vena cava is the largest vein in the body. And we recall that veins go towards the heart. The vena cava is going from the body to the heart. So it also has deoxygenated blood. So we can eliminate that choice. E. Is the pulmonary vein pulmonary again meaning lungs. And we want to look at the vein going toward the heart and from the lungs. So look there. The pulmonary vein we see has oxygenated blood. So that's going to be our answer. Since we're looking for something that does not carry deoxygenated blood. And let's just double check our answer. D. Hepatic vein. Hepatic meaning liver vein towards the heart bringing deoxygenated blood from the liver to the heart. So deoxygenated can't be our answer. And of course pulmonary vein the only vein in the body that does have oxygenated blood. Um as we checked on our diagram here, hope that helped you in the next video.

If a molecule of CO₂ released into the blood in your left toe is exhaled from your nose, it must pass through all of the following except
a. The pulmonary vein.
b. The trachea.
c. The right atrium.
d. The right ventricle.

Verified video answer for a similar problem:

Key Concepts

Circulatory System

Pulmonary Circulation

Respiratory System

If a molecule of CO2 released into the blood in your left toe is exhaled from your nose, it must pass through all of the following except a. The pulmonary vein. b. The trachea. c. The right atrium. d. The right ventricle.

Verified video answer for a similar problem:

Key Concepts

Circulatory System

Pulmonary Circulation

Respiratory System

If a molecule of CO₂ released into the blood in your left toe is exhaled from your nose, it must pass through all of the following except
a. The pulmonary vein.
b. The trachea.
c. The right atrium.
d. The right ventricle.