Which circuit carries blood to the lungs for gas exchange and returns it to the heart?

Which circuit carries blood to the lungs for gas exchange and returns it to the heart?

• A. Systemic Circuit
• B. Pulmonary Circuit
• C. Coronary Circulation
• D. Hepatic Portal Circulation

Answer: (B)

The main idea here is distinguishing the routes blood takes to reach the lungs versus the rest of the body. The circulation that carries blood to the lungs for gas exchange and returns it to the heart is the pulmonary circuit. It starts with deoxygenated blood being pumped from the right ventricle into the pulmonary trunk, which splits into pulmonary arteries that carry blood to the lungs. In the lungs, blood flows through capillaries surrounding the alveoli where carbon dioxide is released and oxygen is picked up. The now-oxygenated blood returns to the heart via the pulmonary veins into the left atrium. This circuit operates under lower pressure because the lungs are nearby and require only a short, thin-walled network for efficient gas exchange. In contrast, the systemic circuit sends blood to the rest of the body, the coronary circulation nourishes the heart muscle, and the hepatic portal circulation routes blood from the digestive organs to the liver.

The main idea here is distinguishing the routes blood takes to reach the lungs versus the rest of the body. The circulation that carries blood to the lungs for gas exchange and returns it to the heart is the pulmonary circuit. It starts with deoxygenated blood being pumped from the right ventricle into the pulmonary trunk, which splits into pulmonary arteries that carry blood to the lungs. In the lungs, blood flows through capillaries surrounding the alveoli where carbon dioxide is released and oxygen is picked up. The now-oxygenated blood returns to the heart via the pulmonary veins into the left atrium. This circuit operates under lower pressure because the lungs are nearby and require only a short, thin-walled network for efficient gas exchange. In contrast, the systemic circuit sends blood to the rest of the body, the coronary circulation nourishes the heart muscle, and the hepatic portal circulation routes blood from the digestive organs to the liver.