Urinary Bladder - 40X

The wall of the urinary bladder has four layers. From the inside towards the outside they are: mucosa, submucosa, muscularis, and serosa or adventitia. The outside layer is either serosa or adventitia, depending on location--see your textbook for an explanation. Some authorities do not include a submucosa in the wall of the urinary bladder--in their opinions, all of the connective tissue (ct) between the mucosa and the muscularis is part of the lamina propria of the mucosa.

In this image, the thickness of the epithelial part of the mucosa--transitional epithelium-- is shown by the bar and labeled e. To the left of the epithelium is the connective tissue (ct) that includes both the lamina propria of the mucosa and the submucosa. To the left of the connective tissue is the muscularis of the urinary bladder, which is called the detrussor muscle.

Urinary Bladder - 100X
The bar shows the thickness of the transitional epithelium lining the urinary bladder. To the left of the epithelium is connective tissue comprising the lamina propria of the mucosa and the submucosa. To the right of that is smooth muscle of the muscularis.

Urinary Bladder - 400X
If you can recognize this as transitional epithelium, you can narrow the location down considerably. It is found in only three organs: ureters, urinary bladder, and part of the urethra. The ureter and urethra are tubes and would probably look like a cross section of circular structure with a lumen. On the other hand, a slide of the urinary bladder can include only a portion of the organ's wall.

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