Glossary of Terms
Blood vessels that carry blood away from an organ, as opposed to arteries which carry blood toward an organ. Examples of organs are the kidneys, the liver, the brain and the heart. Within the organ, oxygen and nutrients are extracted and carbon dioxide (CO2) is added to the blood. The exceptions are pulmonary veins, which transport newly oxygenated blood from the lungs to the left heart. With this exception, the un-oxygenated blood in the veins eventually flows back to the right side of the heart, which then pumps this blood to the lungs where the CO2 is removed and oxygen is added. The newly oxygenated blood is then transported by the pulmonary veins to the left heart, where it is pumped back out to the body.