An example of the circulatory system is the functioning of the human heart, blood and blood vessels.
- The system of structures in vertebrates consisting of the heart, blood vessels, and lymphatics, by which blood and lymph are circulated throughout the body.
- A similar system by which a fluid, such as hemolymph, is distributed in other animals.
Arteries (red) carry blood rich in oxygen from the heart to tissues of the body. Veins (blue) carry blood low in oxygen back to the heart.