1.
T. mucosa: epithelium is transitional, about 3-14 cell-layered; lymphocytes may be found in between cells, particularly in Ruminants.
a)
Lamina propria: loose CT, Elastic fibers, lymphatic nodules may be present.
b)
Lamina muscularis: may be present. In ruminants, dogs, pigs- externally thin, and in horses- well developed, and in cats- absent