Bladder/Urethra

Question 1

What is the cloaca?

Answer 1

A common cavity where merging of the genitourinary and intestinal systems meet.

Question 2

What is the cloaca derived from?

Answer 2

It is aka the distal hind gut, so it is endoderm

Question 3

At around 7 weeks, what divides the cloaca and what are the two anterior/posterior structures created by this separation?

Answer 3

The urorectum septum divides the cloaca into an anterior urogenital sinus and posterior rectum.

Question 4

What is the urogenital sinus derived from?

Answer 4

As the anterior cloaca, it is derived from endoderm

Question 5

Describe the three parts of the urogenital sinus (upper, pelvic, and phallic)

Answer 5

Upper = bladder.  
Pelvis = prostatic urethra, entire female urethra. 
Phallic = genital tubercle, distal male urethra.

Question 6

What is the structure where the mesonephric duct fuses to the urogenital sinus?

Answer 6

The verumontanum.

Question 7

What parts of the bladder are derived from mesoderm?

Answer 7

The trigone and ureteric orifice (via the mesonephros -> ureteric bud)

Question 8

The bladder is mostly derived from what?

Answer 8

Endoderm (as it is the upper anterior cloaca)

Question 9

In females, the entire floor of the urethra is derived from ___.

Answer 9

Mesoderm (* random trivia fact)

Question 10

The median umbilical ligament in the adult comes from what structures?

Answer 10

Allantois -> urachus -> median umbilical ligament

Question 11

A persistent urachus puts the adult at risk of what?

Answer 11

Adenocarcinoma, seen at the dome of the bladder. It is one of the few indications for a partial cystectomy.

Question 12

The urogenital sinus starts developing at the ___ week .

Answer 12

8th

Question 13

The bladder develops between weeks ____ to ____.

Answer 13

9 to 12