Changes

==Histology==

==Histology==

*Epithelium is columnar.

The epithelium of the rectum is '''columnar'''. '''Goblet cells''' are present in the mucosa.

*Goblet cells are present in the mucosa.

===Recto-Anal Junction===

===Recto-Anal Junction===

[[Image:Recto-Anal Junction.jpg|thumb|right|150px|Recto-Anal Junction © RVC 2008]]

[[Image:Recto-Anal Junction.jpg|thumb|right|250px|Recto-Anal Junction © RVC 2008]]

*Termination of the lamina muscularis and longitudinal layer of the tunica muscularis.

The junction marks the termination of the '''lamina muscularis''' and longitudinal layer of the '''tunica muscularis'''. The circular layer of the '''tunica muscularis''' forms the '''internal anal sphincter'''. The '''external anal sphincter''' is formed from skeletal muscle. At the junction, the epithelium changes from columnar to stratified squamous non-keratinised.

*The circular layer of the tunica muscularis forms the internal anal sphincter.

*The external anal sphincter is formed from skeletal muscle.

*Epithelium changes from columnar to stratified squamous non-keratinised.

==Links==

==Links==