What type of blood vessels carry deoxygenated blood back to the heart?

Veins are the type of blood vessels responsible for returning deoxygenated blood back to the heart. They carry blood that has delivered its oxygen to tissues and collected carbon dioxide and other waste products for removal. The structure of veins facilitates this function; they have thinner walls compared to arteries and often contain valves that ensure blood flows in the correct direction, preventing backflow.

In the cardiovascular system, arteries primarily transport oxygen-rich blood away from the heart to various body tissues, while capillaries are small blood vessels where the actual exchange of gases, nutrients, and waste occurs between blood and cells. Venules are small veins that collect blood from capillaries and merge to form larger veins. While venules contribute to the return of blood to the heart, they are not the primary vessels that carry deoxygenated blood; that role is fulfilled by veins.