Template:POTD/2011-05-09
A simplified diagram of the human circulatory system (anterior view), the organ system that passes nutrients, gases, hormones, blood cells, etc. to and from cells in the body to help fight diseases and help stabilize body temperature and pH to maintain homeostasis. This system may be seen strictly as a blood distribution network, but some consider the circulatory system as composed of the cardiovascular system, which distributes blood, and the lymphatic system, which distributes lymph. In this diagram, red indicates blood vessels that carry oxygenated blood, while blue indicates those that carry deoxygenated blood.Image: Mariana Ruiz Villarreal