Urinary Bladder Development

Question 1

Vesicourethral canal

Answer 1

Forms urinary bladder except trigone

Question 2

Allantois

Answer 2

1. Proximal part is incorporated into urinary bladder apex, while distal part becomes fibrosed forming urachus
2. In adult, represented by median umbilical ligament

Question 3

Lower parts of 2 mesonephric ducts

Answer 3

Check book too complicated
Form trigone
1. Mesonephric ducts roots open into vesicourethral canal
2. Then mesonephric ducts distal portions
3. Attached ureteric ducts become incorporated into bladder posterior wall, so 2 mesonephric ducts & 2 ureters open separately into urinary bladder
4. Finally 2 ureters open in urinary bladder postero-superior angles while 2 mesonephric ducts (ejaculatory ducts) open in prostatic urethra upper part
5. Since mesonephric ducts and ureters are mesodermal, trigone is also mesodermal, but with time, trigone lining is replaced by endoderm

Question 4

Congenital anomalies

Answer 4

1. Persistence of patent urachus
2. Bladder exstrophy
3. Cloaca exstrophy

Question 5

Persistence of patent urachus

Answer 5

1. Urachal fistula: persistence of whole urachus patent
2. Urachal cyst: persistence of isolated segment of urachus patent
3. Urachal sinus: persistence of upper part of urachus patent

Question 6

Bladder exstrophy

Answer 6

Ventral body wall defect in which bladder mucosa is exposed
probably due to failure of lateral body wall folds to close in pelvic region midline

Question 7

Cloaca exstrophy

Answer 7

More severe ventral body wall defect in which progression and
closure of lateral body wall folds are disrupted to a greater degree than is observed in bladder exstrophy