The bladder

The bladder also has a lining of transitional epithelium, beneath which is a layer of fibrous tissue resembling that of the renal pelvis, but of greater thickness. The muscular coat, which comes next, is thick and composed of bundles of smooth muscular fibers, interlacing in various directions or disposed in more or less well-defined strata. External to the muscular coat is a fibrous coat, which is covered by a reflection of the peritoneum for a part of its extent, and in other situations passes into the surrounding areolar tissue.

The spear-shaped cells of the transitional epithelium of the bladder have thicker processes than those of the pelvis or ureter; but when detached and macerated in the urine it is often very difficult to determine from their appearance from what part of the urinary tract such cells were derived.