Cloaca

Question 1

Cloaca

Answer 1

Expanded hindgut caudal part (caudal to allantois origin)

Question 2

Division

Answer 2

Urorectal septum arises in angle between allantois and hindgut, it grows caudally dividing cloaca into:
1. Anterior part (primitive urogenital sinus)
2. Posterior part (recto-anal canal)
Primitive urogenital sinus is subdivided by entrance point of mesonephric duct into:
1. Upper part (vesicourethral canal)
2. Lower part (definitive urogenital sinus) which is divided into upper segment (pelvic part) and lower segment (phallic part)

Question 3

Fate: vesicourethral canal

Answer 3

Gives rise to:
1. Urinary bladder except trigone
2. Preprostatic and upper ½ of prostatic urethra (in♂), whole urethra (in ♀)

Question 4

Fate: definitive Urogenital sinus

Answer 4

1. Pelvic part: Gives rise to lower ½ of prostatic and membranous urethra (in ♂)
2. Phallic part : Gives rise to most of spongy urethra (in ♂) and vestibule of vagina (in ♀)