What circuit is responsible for pumping venous blood to the lungs?

The pulmonary circuit is the correct answer because it is specifically designed to transport deoxygenated blood from the right side of the heart to the lungs. In this circuit, blood is pumped out through the pulmonary arteries, where it travels to the lungs to receive oxygen and release carbon dioxide. Once the blood becomes oxygenated in the lungs, it returns to the left side of the heart through the pulmonary veins, ready to be distributed to the rest of the body.

In contrast, the systemic circuit is responsible for delivering oxygen-rich blood from the left side of the heart to the rest of the body, supplying organs and tissues with the oxygen they need for metabolism. The coronary circuit specifically refers to the supply of blood to the heart muscle itself, ensuring that the heart has enough blood flow to function properly. The portal circuit pertains to the pathway that carries blood from the gastrointestinal tract and spleen to the liver, involving substances absorbed from food. Each of these circuits serves distinct functions that are essential for maintaining overall circulatory and metabolic health.