human digestive system

made up of a long muscular tube with its associated glands

glands produce enzymes which break down large molecules into smaller ones ready for absorption. 

Oesophagus-  carries food from the mouth to the stomach. Its main role therefore is transport rather digestion or absorption. It is made up of a thick muscular wall. 

stomach-   a muscular sac that has an inner layer which produces enzymes. Its role is to store and digest food, mainly proteins. Glands in the stomach produces enzymes which break down proteins. The stomach wall contains glands which produce mucus. The mucus prevents the stomach being digested by its own enzymes

small intestine- food is further digested in the small intestine (a long muscular tube) by enzymes that are produced in its walls and glands which pour their secretions into it. .  The surface of the small intestine is covered with villi, which give it a large surface area. The surface area of the villi are further increased by tiny projections called microvilli which adapt the small intestine for its purpose of absorption of food molecules into the bloodstream 

Large intestine-  absorbs water. Most of the water which is reabsorbed comes from the secretions of the many digestive glands. The food within the large intestine therefore becomes drier and thicker in consistency and forms…