GACE Middle Grades Science Practice Exam

The function of veins in the circulatory system is primarily to carry blood back to the heart from various parts of the body. This process involves collecting deoxygenated blood from smaller blood vessels known as venules. Veins have thinner walls compared to arteries and often contain valves that prevent the backflow of blood, ensuring that it moves in one direction toward the heart. This is essential for maintaining an efficient circulatory system, as it allows the heart to effectively pump blood to the lungs for oxygenation and then pump it out to the rest of the body.

In contrast, while arteries carry oxygenated blood from the heart to the body, veins are specifically responsible for returning that blood. Additionally, functions such as regulating heartbeats and distributing nutrients are managed by other components of the circulatory system or associated organs, and do not fall under the primary role of veins.