Which vein carries deoxygenated blood back to the heart from the body systems?

The vena cava is the vein responsible for carrying deoxygenated blood back to the heart from the body systems. There are two vena cavae: the superior vena cava, which collects blood from the upper body, and the inferior vena cava, which collects blood from the lower body. Once the deoxygenated blood reaches the vena cava, it is directed into the right atrium of the heart, where it will eventually be pumped into the lungs for oxygenation. This process is essential for maintaining the circulation of blood throughout the body and ensuring that oxygen-depleted blood is efficiently returned to the heart.

The pulmonary vein is responsible for transporting oxygenated blood from the lungs to the heart, while the coronary vein primarily drains deoxygenated blood from the heart muscle itself back to the right atrium. "Vella" appears to be a non-standard term in this context and does not pertain to a known biological structure related to blood circulation.