It measures approximately 1.5 m in length and 6.5 cm in diameter, it surrounds the small intestine, in the shape of an arch. It is made up of the cecum, colon, rectum, appendix, anal canal and anus. Here approximately 90% of the water is reabsorbed, which is one of its main functions. There are also bacteria in the large intestine that convert proteins into amino acids. These bacteria produce gases, acids, and vitamins B and K by breaking down amino acids. These vitamins are absorbed here. The contents of the large intestine transition to a semisolid state called feces due to the reabsorption of water. (Tortora G. and Derrickson B.