Understanding Circulation
Blood flows from the heart to the body and back to the heart. This non-stop flow is called circulation. Blood flows through blood vessels. These are hollow muscular tubes. There are three main types of blood vessels.
- Arteries are vessels that carry oxygen-rich blood away from the heart.
- Veins are vessels that return oxygen-poor blood to the heart.
- Capillaries are tiny blood vessels that connect arteries and veins.