Anatomy of Digestion – Part One
of digestion consists of the
that runs from the mouth to the anus. The digestive tract includes mouth, pharynx, esophagus, stomach, small intestine, vermiform appendix, cecum, large intestine, rectum and anus. Liver, gall bladder and pancreas are auxiliary organs of the digestive system which produce secretions for digestion and drain them in small intestine. The digestive tract of an adult measures up to 30 feet in length.
Following is the article that gives the brief explanation of the anatomy of digestive tract in two parts:
In this part we cover mouth, pharynx, esophagus, stomach and small intestine. Remaining are covered in Part Two.
is the first organ in digestion. The food is kept in the mouth. It is almost an oval shaped cavity that contains smaller portion called vestibule and the larger portion is called mouth cavity proper. Vestibule is the space between lips and teeth. The mouth cavity is the place made by the teeth linings, where the tongue rests. There are double row of teeth in mouth and in total thirty two in number. The first process of digestion begins with the food placed in the mouth and crushed by teeth. Thus begins the masculation of food.
is a muscular sac like thing that is used for deglutition after crushing the food. It puts the crushed food into esophagus.
is the muscular canal that acts as a passage of food to the stomach. It is about nine to ten inches in length. The upper portion of the esophagus is narrower than the lower portion. Deglutition is done by the longitudinal muscular fibers of the esophagus.
is a bent curved sac that is situated below the breast bone in the epigastric region. The esophasgus is continued to stomach. Though it is muscular structure, it has four coats: the peritoneal, muscular, cellular and mucous. Stomach is the place where the food is churned and various digestive juices pour in for further digestion in small intestine. The mixture of the food and digestive juice is called as chime. This semi-fluid mixture is sent to duedenum and then to small intestine through pyloric orifice for the subsequent action in the small intestine.
Small intestine is the longest section of the digestive tract. It is about 22 to 25 feet in length and about one inch in diameter. It is divided into duodenum, jejunum, and ileum.
- Small intestine is highly convoluted and contained in the central and lower abdominal cavity. The coats of small intestines are same as the stomach but there is gradual diminution in caliber as it descends. Ducts from auxiliary organs like liver, gallbladder and pancreas enter the
to supply digestive juices that help in the digestion of proteins, fats and carbohydrates.
- The second region is called
that is situated in central abdomen. It is about two fifth of the remaining tract. It is richly supplied with blood. The movements in jejunum are rapid and vigorous.
is the last and longest part of small intestine that measures the remaining three-fifth of the tract. Here the diameter of the intestine is less and the walls of the intestine are thinner. In this part of small intestine the mesentry has more fatty deposits.