The gastrointestinal tract is a long muscular tube which extends from the mouth to the anus. It includes the oral cavity, pharynx, esophagus, stomach, duodenum, small intestine, large intestine, rectum and anus.
The accessory digestive organs are: the salivary glands, liver, gall bladder and pancreas.
There are three salivary glands, the parotid, sublingual and the submandibular.
Food is moved through the digestive tract by peristalsis. Food is mechanically broken down by chewing, churning and mixing, and chemically broken down by digestive enzymes. These enzymes are secreted by both the accessory organs and by glands within the walls of the stomach and small intestine.
The digested products (fats, proteins and sugars) are absorbed through the wall of the digestive system into the blood stream and lymphatic ducts to be used by cells throughout the body. Most absorption takes place in the small intestine through villi located in the intestinal wall.
Any material not absorbed is expelled via the anus.
The diaphragm separates the abdominal cavity from the chest cavity.