It is the lower, or inferior, part of the vena cava—a large vein also made up of the superior vena cava that carries blood from the head, neck, arms, and chest in the upper body to the heart.

In regards to blood flow, deoxygenated blood from the superior and inferior vena cava and the coronary ... The sinus node—the part of the heart's electrical system that generates the heartbeat ...

portal vein and inferior vena cava. Impaired venous return of blood to the heart reduces cardiac output and causes circulatory collapse due to a reflex mediated through the splanchnic nerve 6.