Final answer:
Veins are the blood vessels responsible for carrying blood back to the heart. They have valves to prevent backflow and are aided by skeletal muscle contractions. The superior and inferior venae cavae are the largest veins that lead into the heart.
Step-by-step explanation:
Blood Vessels Carrying Blood to the Heart
The blood vessels that transport blood to the heart are veins. Unlike arteries which carry blood away from the heart, veins are designed to facilitate the return of blood back to the heart after it has circulated through the body. Veins generally carry deoxygenated blood from the various parts of the body except in the case of the pulmonary and umbilical veins which carry oxygenated blood.
Veins are equipped with valves that prevent the backward flow of blood. This is essential in ensuring that the flow of blood remains in one direction towards the heart, despite the lower pressure in the veins compared to arteries. The largest veins in the body are the superior and inferior venae cavae, which drain blood into the right atrium of the heart from the systemic circulation.
Moreover, the skeletal muscles play a vital role in aiding venous return to the heart through their squeezing action. This mechanism is particularly important in the extremities, where blood must travel against gravity to reach the heart.