Gastrointestinal System III

Ano-Rectal Junction, Monkey

The simple columnar epithelium of the rectum changes to stratified squamous. Muscularis mucosa and intestinal glands disappear in the anus. In the lower anal region, the surface stratified squamous epithelium becomes keratinised and there are circumanal glands. Note the smooth muscle of the internal sphincter and the striated muscle of the external sphincter.