[PF2] EXCRETORY pt 3

What is the function of the ureters?

Transport urine from the renal pelvis to the urinary bladder

What type of epithelium lines the ureters, bladder, and urethra?

Urothelium (transitional epithelium)

What is the function of the umbrella cells in the urothelium?

Protect underlying cells against the cytotoxic effects of hypertonic urine

What is the histological structure of basal cells in urothelium?

A single layer of small basal cells resting on a very thin basement membrane

What is the function of the intermediate region in the urothelium?

Contains several layers of cuboidal or low columnar cells

Where are umbrella cells located in the urothelium?

In the apical layer (top) of the urothelium

What is the main function of the ureters' muscularis layer?

Move urine by regular waves of peristalsis

What does the urinary bladder serve as?

A storage organ for urine

What happens to the urothelium thickness in the full bladder compared to the empty bladder?

It is thinner in the full bladder (5-7 cell layers vs. 2-3 layers)

What is the function of the detrusor muscle in the bladder?

Contracts to empty the bladder

What are the histological features of the urinary bladder's urothelium?

Thicker in an empty bladder, with well-developed umbrella cells

What are the layers of the urinary bladder's muscularis?

Inner, middle, and outer layers of smooth muscle

What type of epithelium does the urethra have at its distal end?

Stratified squamous epithelium

What epithelium types are found in the urethra?

Stratified columnar, pseudostratified columnar, and stratified squamous epithelium

What is the length of the male urethra?

About 20 cm

What are the three segments of the male urethra?

Prostatic urethra, membranous urethra, spongy urethra

How long is the prostatic urethra?

3-4 cm

What type of epithelium lines the prostatic urethra?

Urothelium

How long is the membranous urethra?

Short segment

What type of muscle surrounds the membranous urethra?

External sphincter of striated muscle

What type of epithelium lines the membranous urethra?

Stratified columnar and pseudostratified columnar epithelium

How long is the spongy urethra?

About 15 cm

Where is the spongy urethra located?

Enclosed within the erectile tissue of the penis

What type of epithelium lines the spongy urethra?

Stratified columnar and pseudostratified columnar epithelium, with stratified squamous epithelium distally

What is the length of the female urethra?

3 to 5 cm

What type of epithelium lines the female urethra?

Transitional epithelium transitioning to nonkeratinized stratified squamous epithelium

Where is the female urethra epithelium continuous with skin?

At the labia minora

What surrounds the middle part of the urethra in both males and females?

External striated muscle sphincter