A network of tubes that carry blood to and from the body cells

Three Types of Blood Vessels Arteries Veins Capillaries All three carry blood

Arteries Carry blood that is high in oxygen (except for the Pulmonary arteries) Carry blood that is low in waste products (except for the pulmonary arteries) Carry blood away from the heart Contain smooth muscle Most are found deeper in the body

Artery Carrying Blood

Largest Artery is the Aorta

Coronary Artery – carries blood from the heart back to the heart – it feeds itself!

Veins Low in oxygen ( except for the pulmonary veins) High in waste products such as CO 2 ( except for the pulmonary veins) Carries blood back to the heart Made of smooth muscle Thinner than arteries Many are found closer to the surface

Veins contain Valves! Blood flow must “defy gravity” to travel back to the heart Valves prevent the blood from moving backwards

Veins are located near skeletal muscles As skeletal muscles contract they help push the blood toward the heart

Capillaries Smallest vessels – only one cell thick! Include both vein and artery capillaries The only vessel that lets blood in or out Capillaries are very close to individual body cells (no more than 3 or 4 cells away)

Diseases of the Blood Vessels Thrombosis – blood clot inside the blood vessel that prevents the blood from flowing Arteriosclerosis – a build up of plaque inside the blood vessel that restricts the amount of blood that can flow