"Epithelium of the GIT" is an incredible example of a paper on the musculoskeletal system. The epithelial lining of GIT from the oral cavity to the anal canal consists of specialized cells in each of the regions and performs specific functions. The epithelial lining of the esophagus consists mostly of simple cuboidal epithelium. The epithelium also consists of goblet cells which secret mucus to provide lubrication to the food passage as well as protection from the infectious agents entering the digestive system (Tortora 2003). The epithelium of the stomach is of specialized type and formed by different types of cells that perform specific functions.
The epithelium of the stomach has specialized folds or pits known as gastric pits at the end of which are acid-producing cells called parietal cells. Also, chief cells are present which produce the precursor of pepsin, pepsinogen. At the neck of those pits are present the mucus-secreting cells which produce thick alkaline mucus to protect the mucosa from erosion by HCl. Also in the stomach are present different hormone-secreting cells known as gastrin secreting cells etc. (Barret, 2010) The small intestine contains mainly simple columnar epithelium and a few goblet cells that secret mucus for protection.
From proximal to distal i. e. duodenum, jejunum, and ileum, the simple columnar epithelium is lined by numerous villi and contains plicae. These villi and plicae decrease in quantity when moving from duodenum to ileum. The main function of the villi in the secretion of mucus and movement of the mucinous layer (Guyton, 2000). The major functions of the epithelium of the small intestine are the absorption of proteins and fats and transfer them to the liver for further metabolism.
The intestinal wall contains specific folds known as intestinal crypts. The vili and plicae contain numerous small channels for the transfer of food particles to the small capillaries running in between them which then carry the absorbed food to the portal circulation and the liver. The epithelium is mainly of simple columnar with no villi. Goblet cells in this region are scant but there are groups of lymph cells forming Peyer's patches. The main function of the epithelium of the large intestine is to absorb the remaining food particles and transport the fecal material into the rectum from where it is excreted (Guyton, 2000).
Guyton, Arthur C, and John E. Hall. Textbook of Medical Physiology. Philadelphia: Saunders, 2000. Print.
Barrett, Kim E, and William F. Ganong. Ganong's Review of Medical Physiology. New York: McGraw-Hill Medical, 2010. Internet resource.
Tortora, Gerard J, and Sandra R. Grabowski. Principles of Anatomy and Physiology. New York: Wiley, 2003. Print.