Changes

==Histology==

==Histology==

*Columnar epithelium

The avian vent and cloaca consist of columnar epithelium. Stratified squamous epithelium are present at the external opening of vent and in the '''caudal proctodeum'''. There are broad folds of mucous membrane forming crypts, which branch near their base. Lymphoid tissue is present in the submucosa. The fold of mucous membrane covering the entrance to the bursa is composed of; columnar epithelium, muscle, connective tissue and goblet cells. There are 2 layers of tunica muscularis; '''Inner circular''' and '''Outer longitudinal'''.

 

*Stratified squamous epithelium at external opening of vent and in the caudal proctodeum

 

*Broad folds of mucous membrane

 

*Crypts present which branch near their base

 

*Lymphoid tissue present in the submucosa

 

*The fold of mucous membrane covering the entrance to the bursa is composed of columnar epithelium, muscle, connective tissue and goblet cells

 

*2 layers of tunica muscularis

**Inner circular

**Outer longitudinal

==Species Differences==

==Species Differences==