Normal Urothelium : Umbrella Cells

Note the prominent umbrella cell layer. The basal cells are separated from the underlying lamina propria by a thin basement membrane. The lamina propria is a highly vascular zone consisting of capillaries, lymphatic channels, sensory nerves, and elastic fibers. The lamina propria also contains thin delicate bundles of smooth muscle known as muscularis mucosae which are usually associated with prominent medium-sized blood vessels.