Ch 20 Embryology Of The Genitourinary Tract

Question 1

Sexual differentiation of the external genitalia is dependent on _______

Answer 1

SRY gene
- located on the short am of the Y chromosome
- directs testicular development

Question 2

At __ weeks gestation, Leydig cells appear in the testits and begin to secrete testosterone.

Answer 2

9 weeks AOG

Question 3

What is the more potent androgen?

Answer 3

Dihydrotestosterone

Question 4

Metabolic conversion of testosterone to DHT is mediated by?

Answer 4

Type 2 5 alpha reductase
- expressed in urogenital sinus and genital tubercle
- required for normal penile and prostatic development

Question 5

What is the first sign of masculinization — described as the increase in distance between the anus and genital structures?

Answer 5

Anogenital distance

This is followed by the elongation of the genital tubercle and formation of a urethral plate

Question 6

Skin of the phallus arises from?
A) Ectoderm
B) Mesoderm
C) Endoderm

Answer 6

Ectoderm

Question 7

Corporal bodies / erectile tissue arise from?
A) Ectoderm
B) Mesoderm
C) Endoderm

Answer 7

B) Mesoderm

Question 8

The urethra and vestibular plate arise from?
A) Ectoderm
B) Mesoderm
C) Endoderm

Answer 8

C) Endoderm

Question 9

The normal ventral penile curvature, or chordee, resolves by ___ week gestation gestation.

Answer 9

20th week of gestation

Question 10

The fetal kidneys develop from which of the following embryonic structures?

a. Paraxial (somite) mesoderm
b. Intermediate mesoderm
c. Neural tube
d. Lateral mesoderm

Answer 10

b. Intermediate mesoderm

Question 11

At what gestational time point does the metanephros development begin?

a. 2 weeks
b. 3 weeks
c. 4 weeks
d. 5 weeks

Answer 11

c. 4 weeks

Question 12

The fused lower pole of the horseshoe kidney is trapped by which of the following structures during the ascent?

a. Inferior mesenteric artery
b. Superior mesenteric artery
c. Celiac artery
d. Common iliac artery

Answer 12

a. Inferior mesenteric artery

Question 13

The homozygous gene disruption (gene knockout) in which of the following molecules does NOT lead to a significant renal maldevelopment in mice?

a. WT-1
b. Pax-2
c. GDNF
d. p53

Answer 13

d. p53

Question 14

Which of the following statements is NOT TRUE of GDNF?

a. It is a ligand for the RET receptor tyrosine kinase.
b. GDNF gene knockout mice demonstrate an abnormal renal development.
c. It is expressed in the metanephric mesenchyme but not in the ureteric bud.
d. GDNF arrests the ureteric bud growth in vitro.

Answer 14

d. GDNF arrests the ureteric bud growth in vitro.

Question 15

The bladder trigone develops from which of the following structures?

a. Mesonephric ducts
b. Müllerian ducts
c. Urogenital sinus
d. Metanephric mesenchyme

Answer 15

c. Urogenital sinus

Question 16

Which of the following statements is NOT TRUE of bladder development?

a. The bladder body and trigone is derived from the urogenital sinus and not the terminal portion of the mesonephric ducts.
b. Bladder compliance seems to be low during early gestation, and it gradually increases thereafter.
c. Epithelial-mesenchymal inductive interactions appear to be necessary for proper bladder development.
d. Histologic evidence of smooth muscle differentiation begins near the bladder neck and proceeds toward the bladder dome.

Answer 16

d. Histologic evidence of smooth muscle differentiation begins near the bladder neck and proceeds toward the bladder dome.

Question 17

The primordial germ cell migration and the formation of the genital ridges begin at which time point during gestation?

a. Third week
b. Fifth week
c. Seventh week
d. Ninth week

Answer 17

b. Fifth week

Question 18

Which of the following statements is NOT TRUE of the paramesonephric (müllerian) ducts?

a. Both male and female embryos form paramesonephric (müllerian) ducts.
b. In male embryos, the paramesonephric ducts degenerate under the influence of the MIS (müllerian-inhibiting substance) produced by the Leydig cells.
c. In male embryos, the paramesonephric ducts become the appendix testis and the prostatic utricle.
d. In female embryos, the paramesonephric ducts form the female reproductive tract, including fallopian tubes, uterus, and upper vagina.

Answer 18

b. In male embryos, the paramesonephric ducts degenerate under the influence of the MIS (müllerian-inhibiting substance) produced by the Leydig cells.

Question 19

Which of the following structures in the male reproductive tract develops from the urogenital sinus?

a. Vas deferens
b. Testis
c. Prostate
d. Appendix of epididymis

Answer 19

c. Prostate

Question 20

Which of the following statements is NOT TRUE of normal prostate development?

a. It requires the conversion of testosterone into dihydrotestosterone by 5α-reductase.
b. It is dependent on epithelial-mesenchymal interactions under the influence of androgens.
c. It is first seen at the 10th to 12th week of gestation.
d. It requires the effects of MIS.

Answer 20

d. It requires the effects of MIS.

Question 21

In female embryos, the remnants of the mesonephric ducts persist as the following structures EXCEPT:

a. epoophoron.
b. paroophoron.
c. hymen.
d. Gartner duct cysts.

Answer 21

c. hymen.

Question 22

Testicular descent occurs during thai time period in utero:
A. 10-15 weeks AOG
B. 12-19 weeks AOG
C. 6-12 weeks AOG
D. Testicular descent begins in the perinatal period after delivery

Answer 22

A. 10-15 weeks AOG
B. 12-19 weeks AOG
C. 6-12 weeks AOG
D. Testicular descent begins in the perinatal period after delivery

Question 23

The process of normal gonadal sexual differentation is determined by this chromosomal region
A. SRY region on the short arm of the Y chromosome
B. HOX gene sequence on the long arm of the X chromosome
C. TDY region on the short arm of the Y chromosome
D. HOX gene sequence on the long arm of the Y chromosome

Answer 23

A. SRY region on the short arm of the Y chromosome

B. HOX gene sequence on the long arm of the X chromosome

C. TDY region on the short arm of the Y chromosome

D. HOX gene sequence on the long arm of the Y chromosome

Question 24

What is the embryonic origin?

Ovarian follicles

Answer 24

Cortex of the indifferent gonad

Question 25

What is the embryonic origin? **Rete ovarii**

Answer 25

Medulla of indifferent gonad

Question 26

What is the embryonic origin? **Round ligament of the uterus**

Answer 26

Gubernaculum

Question 27

What is the embryonic origin? **Epoophroon**

Answer 27

Mesonephric tubules

Question 28

What is the embryonic origin? **Ureter and pelvis**

Answer 28

Mesonephric duct

Question 29

What is the embryonic origin? **Glomerulus**

Answer 29

Metanephric mesenchyme

Question 30

What else arises from the metanephric mesenchyme?

Answer 30

- Glomerulus - Distal convoluted tubule - Proximal convoluted tubule

Question 31

What is the embryonic origin? **Collecting tubule of the kidney**

Answer 31

Mesonephric duct

Question 32

From what embryologic structure does the **uterus and cervix** arise?

Answer 32

Paramesonephric duct

Question 33

What is the embryonic origin? **Skene Glands**

Answer 33

Urogenital sinus UGS: Skene glands, prostatic utricle, prostate, vagina

Question 34

What is the embryonic origin? **Clitoris**

Answer 34

Genital tubercle

Question 35

What is the embryonic origin? **Corpus spongiosum**

Answer 35

Genital tubercle

Question 36

What is the female homologue of the ff? **Seminiferous tubules**

Answer 36

Ovarian follices

Question 37

What is the female homologue of the ff? **Rete testis**

Answer 37

Ovarian hilum

Question 38

What is the female homologue of the ff? **Appendix of epididymis**

Answer 38

Anterior superior vaginal wall

Question 39

What is the female homologue of the ff? **Appendix of testis**

Answer 39

Fallopian tube

Question 40

What is the female homologue of the ff? **Ventral aspect of penis**

Answer 40

Labia minora

Question 41

Multicystic dysplastic kidneys (MCDK) are formed from an abnormal signaling between the ureteral bud and the metanephric blastema. It can be differentiated from autosomal polycystic kidney disease by the following phenotype A. MCDK generally portend a better prognosis compared to autosomal dominant polycystic kidney disease (ADPKD) B. MCDK generally portend a better prognosis compared to autosomal recessive polycystic kidney disease (ARPKD) C. MCDK is generally unilateral, while PKD is usually bilateral D. MCDK is generally bilateral, while PKD is usually unilateral

Answer 41

A. MCDK generally portend a better prognosis compared to autosomal dominant polycystic kidney disease (ADPKD) **B. MCDK generally portend a better prognosis compared to autosomal recessive polycystic kidney disease (ARPKD)** C. MCDK is generally unilateral, while PKD is usually bilateral D. MCDK is generally bilateral, while PKD is usually unilateral

Question 42

The following is *TRUE* about the reciprocal induction of the metanephric mesenchyme and ureteric bud: A. The metanephric mesenchyme induces the ureteric bud to elongate and branch. The ureteric bud induces the metanephric mesenchyme to undergo tubular epithelial conversion. B. The ureteric bud induces the metanephric mesenchyme to elongate and branch. The metanephric mesenchyme induces the ureteric bud to undergo tubular epithelial conversion. C. The ureteric bud induces the metanephric mesenchyme to undergo ingrowth into the surrounding endodermal layer. The metanephric mesenchyme induces the ureteric bud to undergo condensation and tubularization. D. The metanephric mesenchyme induces the ureteric bud to undergo ingrowth into the surrounding endodermal layer. The ureteric bud induces the metanephric mesenchyme to undergo condensation and tubularization.

Answer 42

**A. The metanephric mesenchyme induces the ureteric bud to elongate and branch. The ureteric bud induces the metanephric mesenchyme to undergo tubular epithelial conversion.** B. The ureteric bud induces the metanephric mesenchyme to elongate and branch. The metanephric mesenchyme induces the ureteric bud to undergo tubular epithelial conversion. C. The ureteric bud induces the metanephric mesenchyme to undergo ingrowth into the surrounding endodermal layer. The metanephric mesenchyme induces the ureteric bud to undergo condensation and tubularization. D. The metanephric mesenchyme induces the ureteric bud to undergo ingrowth into the surrounding endodermal layer. The ureteric bud induces the metanephric mesenchyme to undergo condensation and tubularization.

Question 43

Urine production by the metanephric kidney begins at: A. 10th week AOG B. 7th week AOG C. 12th week AOG D. 14th week AOG

Answer 43

**A. 10th week AOG** B. 7th week AOG C. 12th week AOG D. 14th week AOG

Question 44

The following transcription factor is the only absolutely essential factor for *nephric duct formation*: A) LIM1 B) PAX2 C) SIM1 D) PAX1

Answer 44

**A) LIM1** B) PAX2 C) SIM1 D) PAX1

Question 45

The *kidneys ascend* to the upper lumbar region from the pelvis between the following weeks AOG: A) 6-9th weeks AOG B) 4-5th weeks AOG C) 9-12th weeks AOG D) 12-16th weeks AOG

Answer 45

**A) 6-9th weeks AOG** B) 4-5th weeks AOG C) 9-12th weeks AOG D) 12-16th weeks AOG