In a closed circulatory system blood is completely enclosed within?

In a closed circulatory system, blood is completely enclosed within blood vessels, including arteries, veins, and capillaries. This system allows for efficient transport of nutrients, gases, and waste products throughout the body. Unlike open circulatory systems, where blood flows freely in body cavities, the closed system maintains higher pressure, facilitating rapid circulation and precise regulation of blood flow. Examples of organisms with closed circulatory systems include humans and other vertebrates.