What is the difference between the pulmonary and systemic circuits?

The pulmonary circuit and the systemic circuit serve distinct functions in the circulatory system, and option B accurately describes this difference. The pulmonary circuit is responsible for transporting deoxygenated blood from the heart to the lungs, where carbon dioxide is exchanged for oxygen. This process is essential for oxygenating the blood before it is returned to the heart.

In contrast, the systemic circuit distributes oxygenated blood from the heart to the rest of the body, supplying tissues and organs with the necessary oxygen and nutrients for their functionality. After delivering oxygen, the blood returns to the heart in a deoxygenated state, ready to enter the pulmonary circuit again.

This distinction emphasizes the roles of each circuit: the pulmonary circuit focuses on gas exchange in the lungs, while the systemic circuit is concerned with delivering oxygenated blood throughout the body. Understanding these roles is crucial for grasping how the heart and circulatory system maintain homeostasis and support cellular metabolism.