TBL21 - Bladder

Question 1

What is the bladder separated from the pubis by? What is the apex of the bladder attached to?

Answer 1

1) The bladder is separated from the pubis by the retropubic space
2) The apex of the bladder is attached to the median umbilical ligament

Question 2

What does the fundus of the bladder form? What does the body of the bladder separate? What forms the neck of the bladder?

Answer 2

1) The fundus, which is opposite the apex, forms the posterior surface of the bladder
2) The body separates the apex and fundus
3) Convergence of the inferolateral surfaces of the body forms the neck of the bladder

Question 3

How can the filled bladder ascend to the level of the umbilicus?

Answer 3

As the bladder fills, it enters the greater pelvis as it ascends in the extraperitoneal fatty tissue of the anterior abdominal wall

Question 4

How is cystotomy performed to prevent peritonitis?

Answer 4

1) As the bladder fills it extends superiorly above the symphysis into the loose areolar tissue between the parietal peritoneum and anterior abdominal wall
2) The distended bladder may be punctured (suprapubic cystotomy) or approached surgically superior to the pubic symphysis for the introduction of indwelling catheters or instruments without traversing the peritoneum and entering the peritoneal cavity
3) Urinary calculi, foreign bodies, and small tumors may also be removed from the bladder through a suprapubic extraperitoneal incision

Question 5

What forms the involuntary internal urethral sphincter and where is it located? What is the function of the internal urethral sphincter?

Answer 5

1) In males, smooth muscle creates an involuntary internal urethral sphincter (aka sphincter vesicae) around the neck of the bladder
2) This sphincter contracts during ejaculation to prevent retrograde ejaculation (ejaculatory reflux) of semen into the bladder

Question 6

In females, does an internal urethral sphincter form? What forms the compressor urethrae muscle and what does it work synergistically with?

Answer 6

1) In females, an internal urethral sphincter is not formed
2) Muscular slips of the pubococcygeus form the compressor urethrae muscle that works synergistically with the external urethral sphincter (to be studied later)

Question 7

In males, where is the fundus of the bladder positioned in relation to the rectum? What covers the superior surface of the bladder? What does reflection of this structure onto the rectum form?

Answer 7

1) In males, the fundus of the bladder is anterior to the rectum
2) A reflection of parietal peritoneum covers the superior surface of the bladder
3) Its reflection onto the rectum forms the rectovesical pouch

Question 8

What is the fundus of the bladder in females associated with? What forms the vesicouterine pouch? What forms the rectouterine pouch (of Douglas)?

Answer 8

1) The fundus of the bladder in females is associated with the vagina
2) Reflection of the parietal peritoneum off the superior surface of the bladder onto the uterus forms the vesicouterine pouch
3) Reflection of the peritoneum off the uterus onto the rectum forms the rectouterine pouch (of Douglas)

Question 9

What forms the angles of trigone of the bladder? What does the neck of the bladder rest on and what does this allow for?

Answer 9

1) In males (and females), the internal urethral orifice and the ureteric orifices form the angles of the trigone of the bladder
2) The neck of the bladder rests on the prostate; thus, the internal urethral orifice opens into the prostatic urethra

Question 10

Why can rupture of the bladder cause urine extravasation either extraperitoneally or intraperitoneally?

Answer 10

1) Rupture of the superior part of the bladder frequently tears the peritoneum, resulting in extravasation (passage) of urine into the peritoneal cavity
2) Posterior rupture of the bladder usually results in passage of urine extraperitoneally into the perineum

Question 11

Why are bladder infections more common in females?

Answer 11

Infections of the urethra, and especially the bladder, are more common in women because the female urethra is short, more distensible, and is open to the exterior through the vestibule of the vagina

Question 12

In males, what is the only structure that courses between the ureters and parietal peritoneum as the ureters pass from the retroperitoneal space in the abdomen to the bladder in the pelvic cavity?

Answer 12

1) In males, the only structure that passes between the ureter and the peritoneum is the ductus deferens
2) It crosses the ureter within the ureteric fold of peritoneum
3) The ureter lies posterolateral to the ductus deferens and enters the posterosuperior angle of the bladder, just superior to the seminal gland

Question 13

What forms the urorectal septum? What does it separate? What forms the bladder? What forms the urethra?

Answer 13

1) A wedge of visceral mesoderm forms the urorectal septum
2) It separates the hindgut derived cloaca into the anterior urogenital sinus and posterior anorectal canal
3) The superior portion of the urogenital sinus forms the bladder
4) Its inferior portion forms the urethra

Question 14

What is the bladder lumen originally continuous with? When this structure is obliterated, what does it form?

Answer 14

1) The bladder lumen is originally continuous with the lumen of the allantois but obliteration of the allantois lumen forms a fibrous cord remnant designated the urachus
2) The urachus connects the apex of the bladder with the umbilicus
3) Postnatally, the urachus becomes the median umbilical ligament

Question 15

What are the ureteric buds formed from? What is the fate of the caudal ends of the mesonephric ducts and the proximal portions of the ureters in both sexes?

Answer 15

1) The ureteric buds are epithelial outgrowths from caudal ends of the mesonephric ducts just prior to their termination in the urogenital sinus
2) In both sexes, the caudal ends of the mesonephric ducts and the proximal portions of the ureters are absorbed into the posterior wall of the bladder

Question 16

Where do the ureteric orifices and the orifices of the mesonephric ducts move during ascension of the kidneys?

Answer 16

During ascension of the kidneys, the ureteric orifices move cranially and the orifices of the mesonephric ducts move inferomedially toward the urethral orifice

Question 17

What defines the trigone of the bladder in its posterior wall? What becomes the ejaculatory ducts in males?

Answer 17

1) The ureteric orifices and the urethral orifice define the trigone of the bladder in its posterior wall
2) Caudal portions of the mesonephric ducts become the ejaculatory ducts in males (to be studied later)

Question 18

What is a characteristic histologic section of the superior wall of the bladder? What constitutes the detrusor muscle? What function does this muscle serve?

Answer 18

1) The covering serosa indicates the histologic section was obtained from the superior wall of the bladder
2) Multiple layers of smooth muscle in the bladder wall constitute the detrusor muscle
3) Urination results from contraction of the detrusor muscle

Question 19

In males, how is contraction of the detrusor muscle and internal urethral sphincter regulated during micturition?

Answer 19

1) The parasympathetic fibers are motor to the detrusor muscle and inhibitory to the internal urethral sphincter of the male bladder
2) Hence, when visceral afferent fibers are stimulated by stretching, the bladder contracts reflexively, the internal urethral sphincter relaxes (in males), and urine flows into the urethra

Question 20

How can a sympathetic response hamper urination in males?

Answer 20

A sympathetic response at moments other than ejaculation(e.g., self- consciousness when standing at the urinal in front of a waiting line) can cause the internal sphincter to contract, hampering the ability to urinate until parasympathetic inhibition of the sphincter occurs

Question 21

What type of tissue is the bladder lined by? What do tight junctions between the surface epithelial cells do for this layer of tissue?

Answer 21

1) Like the renal pelvis and ureters, the bladder is lined by urothelium
2) Tight junctions between the surface epithelial cells make urothelium impermeable to urine

Question 22

When does urothelial thickness vary? When do cells in the upper epithelial layers change shape and position? What occurs to these cells during micturition?

Answer 22

1) Urothelial thickness varies with cyclic changes in urine volume
2) Cells in the upper epithelial layers change shape and position by flattening and sliding over each other when the bladder fills
3) During micturition, the cells return to their resting shape and position

Question 23

Where does lymph from the bladder mainly drain into?

Answer 23

Lymph from the bladder drains mainly into the internal iliac lymph nodes

Question 24

Where does efferent lymph from the internal iliac nodes enter? Where does lymph from the lumbar nodes empty into?

Answer 24

1) Efferent lymph from the internal iliac nodes enters the common iliac lymph nodes that drain into the lumbar lymph nodes
2) Efferent lymph from the lumbar nodes empties into the thoracic duct

Question 25

What reflects onto the superior surfaces of the pelvic cavity viscera? What follows these reflections?

Answer 25

1) Parietal peritoneum reflects from the abdominal wall onto superior surfaces of the pelvic cavity viscera
2) The pelvic pain line follows the contour of the peritoneal reflections

Question 26

What is the superior wall of the bladder above? What do afferent fibers from the superior wall of the bladder accompany and what is the pathway these structures take? Where are visceral pain sensations conveyed by these DRG referred to?

Answer 26

1) The superior wall of the bladder is above the pelvic pain line
2) Afferent fibers from the superior wall accompany sympathetic fibers in a serial retrograde pathway through the inferior hypogastric plexuses, the hypogastric nerves, superior hypogastric plexus, and inferior mesenteric ganglion to the DRG at T12-L2
3) Visceral pain sensations conveyed by these DRG are referred to the hypogastric region

Question 27

Where is the rest of the bladder other than the superior wall in relation to the pelvic pain line? What nerves supply most of the bladder? What do these fibers convey and where?

Answer 27

1) Other than the superior wall, the bladder is below the pelvic pain line
2) Thus, most of the bladder is supplied by afferent fibers that accompany branches of the pelvic splanchnic nerves
3) These sensory fibers convey visceral pain via the DRG at S2-S4 to the perineum and posterior thighs