TY - CHAP M1 - Book, Section TI - Urologic Pathology of the, Lower Urinary Tract, Male GU System and Kidney A1 - Maygarden, Susan A2 - Reisner, Howard M. PY - 2015 T2 - Pathology: A Modern Case Study AB - REVIEW OF NORMAL HISTOLOGY OF THE LOWER URINARY TRACT "QUICK REVIEW"The outflow of the kidneys (renal pelvis, ureters, bladder, and urethra) comprises the lower urinary tract (Figure 13-1). The basic histology is that all are lined by urothelium (transitional epithelium), which covers a connective tissue layer of lamina propria, a variably thick layer of smooth muscle (muscularis propria) and adventitia (Figure 13-2). Urothelium is specialized epithelium that is multilayered with large surface superficial cells (umbrella cells), which can change shape as the bladder dilates and contracts. These contain specialized cell junctions that are resistant to permeation by urine. Beneath this are five to six layers of smaller urothelial cells. The muscularis propria is well developed in the bladder, and coordinated contraction of this muscle (detrusor muscle) helps in emptying the bladder. Muscle is less prominent in the ureters and the urethra. The distal urethra is lined by squamous epithelium, which is continuity with the squamous epithelium of the external genitalia. Both the male and female urethra contain mucinous glands in their walls. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/03/28 UR - accessmedicine.mhmedical.com/content.aspx?aid=1115280592 ER -