During external respiration, deoxygenated blood is pumped from the right ventricle into the pulmonary circuit to undergo gas exchange at the alveoli. As blood flows through the pulmonary capillary beds, it unloads carbon dioxide and binds oxygen before returning to the heart. Which of the following correctly describes the oxygenation state and vascular pathway of the blood immediately after exiting these alveolar capillary beds?
- Oxygenated blood converges into pulmonary venules and veins, which transport it directly to the left atrium of the heart.Answer
- BOxygenated blood flows directly into pulmonary arterioles and arteries, which carry it under high pressure to systemic circulation.
- CDeoxygenated blood travels through pulmonary veins to enter the right atrium for further filtration.
- DDeoxygenated blood drains into the superior vena cava to be pressurized before entering the left ventricle.
Answer
Oxygenated blood converges into pulmonary venules and veins, which transport it directly to the left atrium of the heart.
In the pulmonary circulatory circuit, blood undergoes external gas exchange across the alveolar-capillary membrane, transitioning from deoxygenated to oxygen-rich. Upon exiting the capillary beds, this oxygenated blood converges into pulmonary venules and pulmonary veins, which empty directly into the left atrium so it can be pumped to the rest of the body.
Step-by-Step Solution
Key Concept
Pulmonary Circuit Hemodynamics and Gas Exchange Exceptions
Estimated Time:1m 15s