Digestion

When food enters the mouth (point where food enters the digestive tract) it is moistened and chewed by teeth (allowing the chewing of food to aid in the digestive process) and transforms into a bolus. Once bolus leaves the mouth it goes into the pharynx where it can be swallowed. Then the bolus moves into the esophagus. When bolus reaches the stomach (organ that mixes food and secretes gastric juice), it mixes with acid secretions and turns the bolus into chime (a semi liquid food mass). Next, food is partially digested into the stomach and chyme usually empties from the stomach within 2 to 6 hours depending on the type and size of the meal that was ingested earlier. The pancreas, gallbladder, and liver are close to the stomach and contribute to the digestive process once the chyme reaches the small intestine. Secretions of bile from liver and gallbladder help with digestion and absorption of fat and digestive enzymes and bicarbonate secretions from the pancreas assist in the digestive process. Any material that may not be absorbed into the small intestine enters the large intestine through the sphincter (keeps material from re-entering the small intestine). The colon and rectum are both included in the large intestine. Absorption of water and other vitamins and minerals occurs in the colon. Materials that are not absorbed in the colon are released from the body as feces. The end of the colon is attached to the anus which is the external opening where the feces waste is released from the body.