ANATOMY

Detailed explanation-1: -Oxygen-poor blood returns from the body to the heart through the superior vena cava (SVC) and inferior vena cava (IVC), the two main veins that bring blood back to the heart.

Detailed explanation-2: -Valves in the veins keep blood flowing in the correct direction. Two large veins that lead into the heart are the superior vena cava and inferior vena cava.

Detailed explanation-3: -The blood vessels that carry blood away from the heart are called arteries. The ones that carry blood back to the heart are called veins.

Detailed explanation-4: -Contraction of the skeletal muscles surrounding veins increases the pressure within the veins, pushing open the proximal valve and forcing blood toward the heart. For example, when calf muscles contract during exercise, blood is forced toward the heart, thus increasing venous return.

Detailed explanation-5: -Blood flows through a network of vessels called the circulatory system. When blood returns to your heart, it flows to your lungs to receive oxygen. Then your heart pumps that blood out to the rest of your body, and the process begins again.