Embryology V: UG development
11/15/2009 Nickalus Khan
Questions (1-82)
1. How many kidneys develop in an embryo?
2. What are the names of the kidneys?
3. What is the sequence of development of these kidneys?
4. Which kidney never really has a function (rudimentary)?
5. What is the mesonephric kidney incorporated into?
6. Which kidney is the definitive kidney?
7. All of the kidney is derived from __________.
8. The germ layer in # 7 causes a bulge in the dorsal body wall called what?
9. What is inside this ridge?
10. Where do the mesonephric tubules drain while they are functioning?
11. Describe what happens to the mesonephric tubules.
12. What is found on the medial aspect of the UG ridge?
13. Describe the primitive formation and transport of urine within the UG ridge.
14. What is lateral to the mesonephric duct?
15. Where does the paramesonephric duct drain into?
16. What is formed from the paramesonephric duct?
17. What are the two sources of development for the metanephric kidney?
18. What is formed from the Ureteric Bud?
19. What is formed from the Metanephric blastema?
20. What is the condition when two kidneys fuse as they ascend at their inferior poles?
21. What stops a horseshoe kidney from ascending?
22. What is the cause of a duplicated ureter?
23. What divides the cloaca into UG sinus and ano-rectal canal?
24. What are the three parts of the UG sinus?
25. What was the bladder formerly connected to? What are its vestigial remnants?
26. In males what does the pelvic portion of the UG sinus form? Females?
27. What forms the prostate gland?
28. What is the tip of the penis formed from?
29. What forms the vas deferens?
30. What buds off the mesonephric duct?
31. Describe the movement of ureter and mesonephric duct into their definitive positions.
32. What is a urachal fistula?
33. What is a urachal cyst?
34. What is a Urachal sinus?
35. What seeds the developing gonads?
36. What envelops the germ cells?
37. What are the two divisions of the medullary cords?
Embryology V: UG development
11/15/2009 Nickalus Khan
38. Describe Rete testis.
39. Describe medullary testis.
40. What does the testis cords form?
41. What forms the efferent ducts of the rete testis?
42. What is the sequence of structures through which sperm move?
43. What are the types of cells in the seminifirous tubules and what are their origins?
44. What is the function of sertoli cells? Leydig Cells?
45. If an ovary is to develop, what happens to the primitive sex cords?
46. Does the medulla of an ovary contain much of anything?
47. What does the cortex of an ovary develop from?
48. Where are follicle cells derived from?
49. What is the connective tissue surrounding an ovary?
50. What is the difference in gonadal development of a male and female?
51. What is another name for the mesonephric and paramesonephric ducts?
52. What happens to the paramesonephric ducts? (female)
53. What connects with the paramesonephric ducts in the bladder?
54. What does this paired region give rise to? What is the term for the paired region?
55. In a male, where do the paramesopephric ducts attach?
56. What does the paramesonephric tubercle form in a male?
57. What forms the lower 2/3 of the vagina?
58. What germ layers form the vagina?
59. How is the broad ligament formed?
60. What is the default sex formed without any extra regulatory factors?
61. What factors cause development of a male?
62. What is uterus didelphyis?
63. What causes Atresia of the vagina?
64. As the phallus grows out in a male, what does it pull with it?
65. What forms the glans of the penis?
66. What germ layers form the penile urethra?
67. What forms a line of fusion along the penis?
68. What is an opening on the ventral surface of the penis called?
69. What is an opening on the dorsal surface of the penis called? Ramifications?
70. In a female, what does the genital tubercle become? Urethral folds? Genital swellings?
71. What is the mesenchymal tissue at the inferior pole of the testis that pulls testis through
inguinal canal into scrotum?
72. What is the fold of peritoneum that accompanies the answer to #71? What does it
form?
73. What are some abnormalities of testis descent?
Embryology V: UG development
11/15/2009 Nickalus Khan
74. What is Cryptochirdism?
75. What can cause congenital hernias (in relation to this lecture)?
76. Describe the gubernaculums in females.
End of class questions
77.
78.
79.
80.
81.
The duct system of the metanephric (definitive kidney) is derived from an outgrowth of:
The pelvic part of the UG sinus in the male forms the:
Efferent ducts in the testis are derived from the embryologic:
In the ovary, follicle cells are derived from the:
Explain the basis for an individual having a normal uterus and semblance of upper vagina, but
with agenesis of the lower vagina.
82. What defect in penis development is always seen where there is extrophy of the bladder.
Embryology V: UG development
11/15/2009 Nickalus Khan
Answers:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
Three
Pronephros, Mesonephros, Metanephros
Pronephros is 1st, Mesonephros is middle, and metanephros is last
Pronephros
Male reproductive tract
Metanephric
Intermediate Mesoderm
Urogenital ridge
Nephrogenic cord (cord of mesenchyme) which is where the excretory tubules for the kidneys
develop from
Mesonephric duct
Degenerate and become part of male reproductive tract.
Future gonads
Urine is formed in a sac which then passes into the mesonephric tubules and drains into the
undifferentiated cloaca.
Paramesonephric duct
Cloaca
Female reproductive tract
Uteric Bud, Metanephric Blastema
Ureter, Renal pelvis, minor calyces, major calyces, develops duct system of kidneys (Remember:
Ureteric bud think duct system)
Excretory tubules & nephrons which connect with the Ureteric bud derived ducts
Horeshoe kidney
The fused poles catch on the inferior mesenteric artery
Splitting of ureteric bud
Urorectal septum (endpoint of this septum is perineal body)
Cranial to Caudal: Bladder, Pelvic portion of UG sinus, Phallic portion (pelvic urethra)
Allantois, Urachaus  Median umbilical ligament
Male: Prostatic Urethra, Female: All of urethra
Multiple invaginations of the pelvic UG sinus (part of urethra that travels through here is called
prostatic urethra which is derived mostly from phallic portion of UG sinus)
Cord of ectodermal cells that invaginate to meet the end of the penile urethra (Tip of penis
comes from ectoderm, rest of penis is endodermly derived)
Mesonephric duct incorporates into wall of bladder
Ureteric bud which forms ureter
Ureters move cranially, mesonephric ducts move caudally because of this descent the vas
deferens discharge into the prostatic urethra
Communication of bladder through abdominal wall
Embryology V: UG development
11/15/2009 Nickalus Khan
33. Sinus remaining from allantois, cyst forms between remnants of umbilicus and bladder, can
produce pain and inflammation
34. Opening of bladder to outside, no abdominal covering, must be surgically repaired
35. Germ cells from yolk sac endoderm that migrate up the dorsal mesentery
36. Primitive sex cords derived from epithelial cells
37. Rete testis, and medullary testis
38. Closest to tubules of kidneys
39. Closer to surface, lose connection to the surface and are enveloped by tunica albuginea
40. Seminiforous tubules which connect to the rete testis
41. Mesonephric kidney, which is no longer needed forms these ducts, mesonephric duct gives rise
to vas deferens and duct of epididymis
42. Seminiforous tubules rete testisefferent ductsductus epididymis vas deferens
43. Sertoli cells (develop from surface epithelium), Germ cells (develop from yolk sac endoderm),
Leydig cells (develop from interstitial mesenchyme)
44. Sertoli: nurture sperm, Leydig: Produce testosterone
45. Degenerate (mesonephric duct and tubules completely degenerate)
46. No
47. Second wave of epithelial cells that surround germ cells (cortical cords)
48. Overlying epithelium
49. Still tunica albuginea
50. Male develops medullary cords, but no cortical cords, thick tunica albuginea | female develops
cortical cords but no medullary cords, thin tunica albuginea
51. Mesonephric = wolffian, paramesonephric = mullerian
52. Fuse to form a single opening into the developing bladder
53. Paramesonephric tubercle
54. Uterus and upper 1/3 of vagina, uterovaginal primordium
55. On either side of the paramesonephric tubercle
56. Seminal colliculus which has an attached sac called the utricus prostaticus (prostatic utricle,
vestige of vagina in male)
57. Outgrowth of mullerian tubercle, sinovaginal bulb grows from tubercle and attaches to caudal
tip of paramesonephric duct
58. Upper 1/3 is mesoderm, lower 2/3 is endoderm
59. Tissue carried with paremesonephric ducts as they move to midline to fuse, this movement
partitions pelvis into rectouterine and vesicouterine pouches
60. Female
61. Testosterone, stimulates proliferation of mesonephric ducts, sertoli cells excrete anti mullerian
factor that prevents paramesopephric duct formation
62. Failure of fusion of mullerian (paramesonephric) ducts, forms double uterus and double vagina
63. Failure of fusion to bladder due to failure of development of sinovaginal bulbs
64. Urethral folds, which surround the urethra
65. Phallus (genital tubercle) forms glans penis, folds form shaft of penis
66. Mostly endoderm, except for tip which is ectoderm
67. Genital swellings
68. Hyposdia
69. Epispadia; mesenchyme fails to surround bladder, no anterior abdominal wall (can see directly
into bladder)
70. Clitoris, labium minor, labium majora
71. Gubernaculum
Embryology V: UG development
11/15/2009 Nickalus Khan
72. Vaginal process, forms tunica vaginalis
73. Connection between vaginalis and peritoneal cavity, hydrocele between testis and peritoneum,
74. Undescended testis, testis don’t migrate to the inguinal canal after at least 1 yr of development,
cause is unknown, male is sterile because of this
75. Persistent connection between peritoneal cavity and tunica vaginalis
76. Pulls ovaries down somewhat less than the testis in males, round ligament and ligament of
ovary represent the gubernaculums in females
Answers to end of class questions:
77.
78.
79.
80.
81.
82.
Ureteric Bud
Prostatic and membranous urethra
Mesonephric tubules
Surface epithelium (second wave of sex cords-cortical cords)
The lower vagina comes from a different precursor than the uterus and upper vagina
Epispadia