Large Intestine

          The large intestine extends from the ileocecal junction to the anus and is about 1.5m long. On the surface, you can identify bands of longitudinal muscle fibers called taeniae coli, each about 5mm wide. There are three bands and they start at the base of the appendix and extend from the cecum to the rectum. Along the sides of the taeniae, you will find tags of peritoneum filled with fat, called epiploic appendages (or appendices epiploicae). The sacculations, calledhaustra, are characteristic features of the large intestine, and distinguish it from the rest of the intestinal tract. 

Function:

          The large intestine takes about 16 hours to finish up the remaining processes of the digestive system. Food is no longer broken down at this stage of digestion. The colon absorbs vitamins which are created by the colonic bacteria - such as vitamin K (especially important as the daily ingestion of vitamin K is not normally enough to maintain adequate blood coagulation), vitamin B12, thiamine and riboflavin. It also compacts feces, and stores fecal matter in the rectum until it can be discharged via the anus in defecation.

The large intestine differs in physical form from the small intestine in being much wider and in showing the longitudinal layer of the muscularis have been reduced to 3 strap-like structures known as the taeniae coli. The wall of the large intestine is lined with simple columnar epithelium. Instead of having the evaginations of the small intestine (villi), the large intestine has invaginations (the intestinal glands). While both the small intestine and the large intestine have goblet cells, they are abundant in the large intestine.

The appendix is attached to its inferior surface of the cecum. It contains the least of lymphoid tissue. It is a part of mucosa-associated lymphoid tissue, which gives the appendix an important role in immunity. Appendicitis is the result of a blockage that traps infectious material in the lumen. The appendix can be removed with no damage or consequence to the patient. The large intestine extends from the ileocecal junction to the anus and is about 1.5 m long. On the surface, bands of longitudinal muscle fibers called taeniae coli, each about 5 mm wide, can be identified. There are three bands, and they start at the base of the appendix and extend from the cecum to the rectum. Along the sides of the taeniae, tags of peritoneum filled with fat, called epiploic appendages (or appendices epiploicae) are found. The sacculations, called haustra, are characteristic features of the large intestine, and distinguish it from the small intestine. It is also found in the digestive system.