Blood vessel vessels function to transport blood. In general, arteries and arterioles transport oxygenated blood from the lungs to the body and its organs, and veins and venules transport deoxygenated blood from the body to the lungs. Blood vessels also circulate blood throughout the circulatory system Oxygen (bound to hemoglobin in red blood cells) is the most critical nutrient carried by the blood. In all arteries apart from the pulmonary artery, hemoglobin is highly saturated (95–100%) with oxygen. In all veins apart from the pulmonary vein, the saturation of hemoglobin is about 75%. (The values are reversed in the pulmonary circulation.) In
Blood irradiation therapy sources. It is used only for ultraviolet blood irradiation, that involves drawing blood out through a vein and irradiating it outside of the body. Though promoted as a treatment for cancer, a 1952 review in the "Journal of the American Medical Association" and another review by the American Cancer Society in 1970 concluded the treatment was ineffective. Stephen Barrett, writing for Quackwatch, lists ultraviolet blood irradiation therapy as a questionable treatment. Blood irradiation therapy Blood irradiation therapy is a procedure in which the blood is exposed to low level red light (often laser light) for therapeutic reasons. Most research on