URINARY BLADDER – slides 158 and 160

Slide 158 (human) shows the wall of an empty, contracted bladder.  Since this is postmortem material, the fragile epithelium may be somewhat fragmented, but look for an area with typical transitional epithelium, with puffy, dome-shaped surface cells.  Sometimes these cells are binucleated.

The connective tissue of the lamina propria is quite dense.  Because the deeper portion of this coat is a somewhat looser connective tissue, some people refer to the deeper layer as submucosa.  There is no muscularis mucosae to make two separate layers, however.

The muscularis externa is thick.  Although some bundles of smooth muscle run spirally, the general plan is for three layers of muscle:  inner and outer longitudinal, and middle circular.

The outermost coat is an adventitia for most of the surface of the bladder, since the organ is retroperitoneal in position.  Notice blood vessels and nerves running in all connective tissue layers.