The digestive tract of the amur is like that of other vertebrates in that it is composed of four layers: mucosa, submucosa, muscularis externa and serosa. The mucosa is composed of pseudostratified epithelial tissue and an extremely thin lamina propria and muscularis mucosa. Goblet cells are found throughout this layer of the gut, being most numerous In the posterior part. The submucosa is composed of dense irregular connective tissue. The muscularis externa consists of an inner and an outer layer of smooth muscle fibers. However, in the esophageal region this layer also contains some striated muscle. The serosa is composed of a thin layer of dense irregular connective tissue and a single layer of simple squamous mesothelium.
Morgans, Leland F. and Heidt, Gary A.
"Microscopic Anatomy of the Digestive Tract of the White Amur, Ctenopharyngodon idella Val.,"
Journal of the Arkansas Academy of Science: Vol. 28
, Article 18.
Available at: http://scholarworks.uark.edu/jaas/vol28/iss1/18