Development

Question 1

What is the embryological origin of the genital tract?

Answer 1

Intermediate mesoderm

Question 2

Describe the developmental process of the male reproductive tract

Answer 2

1. Genital Duct formation - Mesonephric (Wolffian) ducts develop in weeks 5-6 and under the influence of testosterone, form ductus deferens and ejaculatory ducts
2. Gonadal Development - Gonads are indifferent until week 7 but originate as primordial germ cells which move to genital ridge to form primitive sex cords. Due to SRY gene, these become horse-shooe shaped and break into tubules whilst leydig cells produce testosterone and sertoli cells produce AMH. The testis cord is solid until puberty where the lumen forms and the seminiferous tubules are formed
3. External genitalia development - Testosterone is converted to DHT for the production of external genitalia, whilst accessory glands develop as outpouchings of already already exisitng structures (prostatic urethra - prostate)

Question 3

Describe the developmental process of the female reproductive tract

Answer 3

1. Genital Duct formation - Paramesonephric (Mullerian) ducts develop in weeks 5-6 laterally to the mesonephric ducts. They form funnel shaped cranial ends and migrate caudally until reach pelvic region where they approach each other in the midline to form uterus and superior vagina
2. Gonadal Development - Gonads are indifferent until week 7 but originate as primordial germ cells which due to absence of SRY gene, and wnt4 (anti-testis), fail to reach genital ridge so gonads regress. somatic cells grow from coelomic epithelium whilst primordial germ cells mitotically divide to produce a pool of oogona (late become associated with follicular cells)
3. External genitalia development - labia minora forms from subdivision of cloacal folds and labia majora as an outpuching of the urethral folds. Sinovaginal bulbs fuse to form vaginal plate which hollows to form a cavity

Question 4

Identify 3 female developmental abnormalities and explain how they are caused

Answer 4

1) Double uterus / Bicornuate uterus results from failure of fusion of mullerian ducts
2) Vaginal atresia is due to failed canalisation
3) Absence of vagina/uterus is a result or failed sinovaginal bulbs

Question 5

What is hypospadias and how can it be treated? How does it differ from epispadias?

Answer 5

Hypospadias - opening of urethra on underside of penis
Epispadia - opening of urethra on top side of urethra

treated surgically by usually using a graft from foreskin

Question 6

Identify 4 Intersex disorders and explain their consequences on the reproductive system

Answer 6

1) Klinefelters syndrome - 47XXY where extra X chromosome causes decreased steroid prouction from leydig cells - low sperm count, gynaecomastia, impaired sexual maturation
2) Testicular feminising syndrome - genetic condition where mutation of X chromosome in males results in decreas in androgen receptors, reducing effect of testosterone
3) Turners Syndrome - single X chromosome so primordial germ cells degenerate quickly, causing failure of gonadal development
4) 5alpha-reductase deficiency - as seen in dominican republic where testosterone cant form DHT so external male genitalia dont form until after puberty.

Question 7

How will congenital adrenal hyperplasia affect the reproductive system of a female?

Answer 7

This is a result of CYP21A2 deficiency - enzyme required for progesterone conversion in order to make aldosterone and cortisol. The body therefore sends signals to encourage the production of these hormones, which also causes the production of testosterone, masculinising baby girls

Question 8

Describe the process of testicular descent

Answer 8

Week 8-15: The presence of INSL3 and AMH causes gubernaculum enlargement, bringing the testes down through inguinal canal

Weeks 28-35: surge of testosterone causes gubernacular migration and completion of testicular descent into scortum

Question 9

Where is AMH produced?

Answer 9

sertoli cells

Question 10

What structures make up the inguinal canal

Answer 10

M- Internal oblique and treansverse abdominus muscles
A- apopneurosis of internal and external oblique
L- Inguinal and lacunar ligaments
T- Conjoint Tendon and transversalis fascia`

Question 11

What is cryptorchidism, how does it develop and how is it treated?

Answer 11

• Failure of testicular descent - bilateral or unilateral
• Endocrine disruptors and genetic conditions which reduce INSL3
• can resolve naturally but if by 6 months haven’t, refer to orchidopexy

Question 12

What are complications of cryptorchidism?

Answer 12

• Reduced fertility

- Risk of testicular cancer