Chapter 13

Question 1

A urachal cyst is a remnant of the
(A) urogenital sinus
(B) urogenital ridge
(C) cloaca
(D) allantois
(E) mesonephric duct

Answer 1

D. The upper end of the urogenital sinus is in patent communication with the allantois, which lies in the umbilical cord. The allantois normally regresses and forms a fibrous cord. If a remnant
persists, it forms a urachal cyst or sinus.

Question 2

The transitional epithelium lining the urinary
bladder is derived from
(A) ectoderm
(B) endoderm
(C) mesoderm
(D) endoderm and mesoderm
(E) neural crest cells

Answer 2

B. The transitional epithelium lining the urinary bladder is derived from endoderm because the urinary bladder develops from the upper end of the urogenital sinus. The origin of the urogenital
sinus can be traced back to the gut tube, which is lined by endoderm.

Question 3

The podocytes of Bowman's capsule are
derived from
(A) ectoderm
(B) endoderm
(C) mesoderm
(D) endoderm and mesoderm
(E) neural crest cells

Answer 3

The podocytes of Bowman’s capsule develop from the metanephric vesicles, which are of mesodermal origin.

Question 4

The proximal convoluted tubules of the
definitive adult kidney are derived from the
(A) ureteric bud
(B) metanephric vesicle
(C) mesonephric duct
(D) mesonephric tubules
(E) pronephric tubules

Answer 4

B. The distal convoluted tubule, loop of Henle, proximal convoluted tubule, and Bowman’s capsule all are derived from the metanephric vesicle.

Question 5

The trigone on the posterior wall of the urinary
bladder is formed by the
(A) incorporation of the lower end of the
mesonephric ducts
(B) incorporation of the lower end of the
pronephric ducts
(C) incorporation of the metanephric
blastema
(D) incorporation of the mesonephric tubules
(E) incorporation of the pronephric tubules

Answer 5

A. The lower end of the mesonephric ducts is incorporated into the posterior wall of the urinary
bladder. The mesonephric ducts contribute to the connective tissue component of the posterior
wall at the trigone. It is generally believed that the transitional epithelium lining the entire bladder (even the trigone) is of endodermal origin.