소순환, or "small circulation," refers to the process of blood circulation within the lungs. In this system, deoxygenated blood is transported from the heart's right ventricle to the lungs through the pulmonary arteries. Here, carbon dioxide is exchanged for oxygen, allowing the blood to become oxygenated. Once the blood is oxygen-rich, it returns to the heart's left atrium via the pulmonary veins. This oxygenated blood is then pumped into the body's larger circulation system, known as 대순환 or "large circulation," to supply oxygen to tissues and organs throughout the body.