Biology

Human Digestive System
The digestion process begins by chewing the food in the mouth which breaks down the food. Salivary and serous glands secrete the digestive enzymes amylase and lingual lipase. These enzymes are present in saliva. When food is chewed, these enzymes mix with food and this mixture is permitted by pharynx to be sent to the oesophagus. The food passes through oesophagus into the stomach. The gastric juice in the stomach is mixed with the food to digest carbohydrates and proteins and convert food into chyme. The chyme is then passed into duodenum, the first part of small intestine. The jejunum and ileum in the lower part of the small intestine are responsible for the absorption of nutrients into the bloodstream. Small intestine is 22 feet long. The food in the small intestine is mixed with the enzymes produced by the pancreas and bile from liver. The gallbladder stores and concentrates bile from the liver and releases it into the duodenum in the small intestine. Most of the food is digested in small intestine. The rest of the food not absorbed by small intestine flows into the large intestine. Water is absorbed in large intestine and remaining waste material is stored in rectum. Rectum holds stool until evacuation through anus. Anus which is 2-inch-long canal is the last part of digestive tract.