Human digestive system the colon or large intestine. Water is absorbed here and the remaining waste matter is stored prior to defecation. Most of the digestion of food takes place in the small intestine. A major digestive organ is the stomach. Within its mucosa are millions of embedded gastric glands. Their secretions are vital to the functioning of the organ. There are many specialised cells of the GI tract. These include the various cells of the gastric glands, taste cells, pancreatic duct cells, enterocytes and microfold cells. Some parts of the digestive system are also part of the excretory system, including the large
Human digestive system are "spent". This is why it is sometimes known as the 'graveyard of red blood cells'. A product of this "digestion" is the pigment bilirubin, which is sent to the liver and secreted in the bile. Another product is iron, which is used in the formation of new blood cells in the bone marrow. Medicine treats the spleen solely as belonging to the lymphatic system, though it is acknowledged that the full range of its important functions is not yet understood. The liver is the second largest organ (after the skin) and is an accessory digestive gland which plays a