Reproductive embryology Flashcards
What does the SRY (sex determining region of the Y chromosome) initiate the production of?
Testis- determining factor
What germ layer do both the urinary and reproductive systems arise from?
The intermediate mesoderm
What ridge does the intermediate mesoderm form in the initial development of the urinary and reproductive systems?
Urogenital ridge
What are the primitive sex chords?
Found in the indifferent gonad at 5-6 weeks
Formed from the proliferating epithelium of the indifferent gonad which penetrates the underlying mesoderm
Where do primordial germ cells migrate from to the urogential ridge in week 6?
Definitive yolk sac
What happens if the primordial germ cells dont migrate?
Indifferent gonad develops no further
What are the medullary chords?
When the indifferent gonad divides into the 2 distinct region, the outer cortex and the inner medulla, the primitive sex chords detach from the cortex to form the medullary chords
What determines what happens to the medullary chords and the cortex in the indifferent gonad?
Presence of TDF
What happens to the indifferent gonad in the presence of TDF?
Medullary cords develop
No cortical cords develop
Thick tunica albuginea develops
What happens to the indifferent gonad in the absence of TDF?
Medullar cords degenerate
Cortical cords develop
No tunic albuginea develops
In the testis as the medullary cords continue to develop what do they form near the hilum?
The rete testis
What is the tunica albuginea?
Connective tissue layer around the testis
What do the remaining medullary cords in the testis form?
The seminiferous tubules which produce spermatoazoa
What do the primordial germ cells give rise to?
Oocytes or spermatazoa
What are the cortical cords in the ovaries?
Medullary cords degenerate and epithelium begins to proliferate and produces a second generation of cords called the cortical cords
Cortical cords then split and surround the oocyte
At how many weeks do. the gonads become distinguishable?
7
What is the gubernaculum?
thickening of the parietal peritoneum
In the male it shortens to facilitate the descent of the testes
For which months do the testes remain at the deep inguinal ring?
3 - 7 months
What pulls the testes through the inguinal canal and into the scrotum?
The shortening of the gubernaculum with the aid of the increased intra abdominal pressure from the growing abdominal organs
What is the process vaginalis and what does it give rise to in the adult?
Pulled down pouch of peritoneum
Gives rise to tunic vaginalis around testis
When should the process vaginalis obliterate in a baby?
Within the first year
What can a patent process vaginalis lead to?
- If it remains open to the abdominal cavity it can lead to an indirect inguinal hernia
- If it is not open to the abdominal cavity can form cysts which become filled with fluid (as made from peritoneum can produce peritoneal fluid) and can swell - hydrocele
What is hydrocele transillumination?
Cysts formed from patent process vaginalis containing fluid (hydrocele) with allow light to pass through easily
What are the symptoms of hydrocele and how can it be solved?
Benign - large cysts can cause discomfort
These can be removed surgically
What is cryptorchidism?
Failure of one or both of the testis to descend
What is cryptorchidism associated with increased risks of?
Testicular cancer and infertility
How is cryptorchidism cured?
Affects 1-4% of births but most spontaneously descend within 3 months, those that dont are corrected surgically within 4-6 months
Where do the ovaries descend to in the female?
Pelvic brim
Where does the gubernaculum insert?
Labia majora
What does the gubernaculum persist as in the adult?
From ovary to uterus = ovarian ligament
From uterus through inguinal canal to labia majora = round ligament
