Ureter -- tube continuous with the renal pelvis which transports urine from kidney by peristalsis (Fig. 19-15).

Examine a section of ureter (slides 16 and 48), noting the highly folded mucosa, surrounded by two layers of smooth muscle and adventitia (Fig. 19-15b). In the folds of the urinary epithelium (or urothelium) note that the basement membrane is extremely thin and is closely associated with capillaries.

How does urinary epithelium protect underlying tissue from the toxic properties of urine?

Why is urinary epithelium not required along the urethra lining?

Bladder -- collects urine from ureters for drainage via urethra

Examine a Masson trichrome-stained section of bladder (slide 12) and examine the folded urinary or transitional epithelium and the collagen in the underlying lamina propria (Fig. 19-16).

• Identify the three layers of smooth muscle and the outer serosa/adventitia.
• The outer layer may contain Pacinian corpuscles.

Why would Pacinian corpuscles be located in the wall of the bladder?

What is the function of the smooth muscle here?

Clinical note: Transitional cell carcinoma, the most common type of bladder cancer, is associated with occupational exposure to certain organic chemicals among workers in the dye, rubber, paint, and some other industries. Smokers also have a fourfold increased risk for bladder cancer compared to nonsmokers.

What might explain the finding that cancer is more common in the bladder than in the kidney or ureter?

Almost there, last comes the urethra.