What is the primary function of veins in the circulatory system?

The primary function of veins in the circulatory system is to transport deoxygenated blood back to the heart. After oxygen is delivered to the tissues and organs through arteries, the blood becomes deoxygenated as it picks up carbon dioxide and other waste products. Veins carry this deoxygenated blood from the various parts of the body back to the heart, where it can then be sent to the lungs for reoxygenation.

This aspect of the circulatory system is critical for maintaining proper circulation and ensuring that the body can effectively expel carbon dioxide and receive fresh oxygen, thereby sustaining cellular function. Understanding this role helps clarify the overall process of circulation, highlighting the unique contributions of veins in returning blood to the heart, contrasting with arteries, which carry oxygen-rich blood away from the heart.