03 The Ureters, Urinary Bladder, and Urethra

What is the basic function of the ureters?

Carry urine from the kidneys to the urinary bladder

How long are the ureters?

30 cm (12 inches)

Where do the ureters start and end?

Start at renal pelvis around L2, enter pelvis over sacroiliac joint, end at the bladder

Are the ureters retroperitoneal or intraperitoneal?

Retroperitoneal

What type of epithelium lines the ureter mucosa?

Transitional epithelium

What is the function of transitional epithelium in the ureter?

Allows stretch and recoil

What surrounds the transitional epithelium in the ureter mucosa?

Fibro-elastic connective tissue with MALT

What layers make up the muscularis of the ureter?

Inner longitudinal, outer circular layers of smooth muscle

What is the function of the ureter muscularis?

Peristaltic contractions that propel urine to the bladder (not gravity!)

What is the outermost layer of the ureter wall?

Adventitia (dense connective tissue)

What is the basic function of the urinary bladder?

Collapsible muscular sac that stores and expels urine

Where is the urinary bladder located?

Inferior to peritoneal cavity, inside the pelvic cavity, posterior to pubic symphysis

Where is the urinary bladder located relative to the prostate in males?

Above the prostate

Where is the urinary bladder located relative to the vagina and uterus in females?

Anterior to vagina, uterus arches over the bladder

Is the urinary bladder typically smaller in males or females?

Smaller in females

What shape is the bladder when empty?

Triangular

What shape is the bladder when full?

Spherical, expands superiorly, palpable above pubic symphysis

What are ureteric orifices?

Posterior/inferior slit-shaped openings where ureters drain into the bladder

What is the bladder neck?

Opening to the urethra on the inferior surface of the bladder

What is the trigone of the bladder?

Triangular area between ureteric orifices and bladder neck

What are rugae in the bladder?

Folds of the mucosa visible when the bladder is empty; disappear when the bladder fills

What type of epithelium lines the bladder mucosa?

Transitional epithelium

What is the function of transitional epithelium in the bladder?

Allows stretch and recoil

What is the lamina propria of the bladder made of?

Fibro-elastic connective tissue

What is the detrusor muscle?

Thick smooth muscle layer of the bladder wall; contracts to expel urine

What layers make up the detrusor muscle?

Inner and outer longitudinal, middle circular smooth muscle

What is the outermost layer of the bladder?

Adventitia (dense connective tissue); superior surface covered by parietal peritoneum

What is the basic function of the female urethra?

Carries urine only

How long is the female urethra?

3-4 cm (1.5 inches)

What is the pathway of the female urethra?

Bladder neck → internal urethral sphincter → external urethral sphincter → external urethral orifice (anterior to vagina, posterior to clitoris)

What type of muscle forms the internal urethral sphincter?

Circular smooth muscle (involuntary)

What type of muscle forms the external urethral sphincter?

Circular skeletal muscle (voluntary)

What is the basic function of the male urethra?

Carries urine and ejaculating semen

How long is the male urethra?

20 cm (8 inches)

What is the pathway of the male urethra?

Bladder → internal urethral sphincter → prostate → external urethral sphincter → penis → external urethral orifice

What are the three regions of the male urethra?

Prostatic urethra, membranous urethra, spongy urethra

What is the prostatic urethra?

Portion of urethra that passes through the prostate

What is the membranous urethra?

Portion of urethra that passes through the urogenital diaphragm

What is the spongy urethra?

Portion of urethra in the corpus spongiosum of the penis