ABSTRACT
The mammalian bladder wall has serous, muscular, and mucosa layers. The mucosa consists of transitional cell epithelium supported by loose connective tissue in which blood vessels, nerve fibers, and occasional reticuloendothelial cells are located. The subepithelial blood capillaries are close to the base of the epithelium and are separated from it only by a thin, uninterrupted basal lamina below the basal epithelial cells. These anatomic structures are readily seen by electron microscopy, but cannot be easily detected by light microscopy. The cytoplasm of superficial cells is not strongly basophilic and contains numerous, large, densely staining autophagic bodies which can be identified by their enzymatic content as large lysosomes in the dog. Tumors of the urinary bladder are very common in cattle of certain parts of the world and are associated with a syndrome known as chronic hematuria or hematuria cancerogenes bovis. In many organs of the body, the diagnosis of malignancy is based on cellular anaplasia, invasion, or metastasis.
