Q. What is the vena cava? Which type of blood circulates within the vena cava?
The vena cava is either of two large veins that debouch into the right atrium the superior vena cava drains all blood that comes from the superior limbs, the neck, the head and the superior portion of the trunk. The inferior vena cava carries blood drained from the inferior limbs and the inferior portion of the trunk and venous blood circulates within the vena cava.