Embryology Flashcards
When does structural vs functional development occur?
Structural - in utero
Functional - after birth
What are the 3 sources of gonad development?
- Condensed mesenchyme (from the genital ridge)
- Colemeic epithelium
- Gonocytes aka primordial cells
What are the adult structures formed by the mesonephric duct vs paramesonephric duct?
Mesonephric duct/Wolff duct becomes the vas deferens and epididymis in males
Paramesonephric duct/Müller duct becomes the uterus and uterine tube in females
Compare the differences in gonadal development in males and females based on these features: gonadal chords, corticol chords, tunica albuginea
Males:
- Gonadal chords develop and have germ cells within that form the forerunner for seminiferous tubules -> connect to rete testis -> leads to epididymis duct
- NO cortical chords
- Thick tunica albuginea
Females:
- Gonadal chords degenerate
- Cortical chords develop (and protrude inwards)
- NO tunica albuginea
As the mesonephros regresses what do the tubules divide into in males and what is their function?
The tubules divide into epigenital and paragenital tubules…
1. Epigenital: joins the rete testis and form an efferent ductule which converges into ductulli efferentes -> vas deferens -> urogenital sinus
- Paragenital: form paradidymis and doesn’t join the chords of rete testis
When does the gubernaculum become active and what does it do in males and females?
Activity begins at the 6th week…
Males: guides the testis down from the future abdomen to its root in the scrotum
Females: rooted in the labia and persists as the ovarian ligament and round ligament which connects the ovary to the uterus and stabilizes the uterus
What is left of the mesonephros in females? List them in order of lateral -> medial What can go wrong at any one of these places?
All of the mesonephros + duct disappears EXCEPT 3 small parts…
- Epoophoron
- Paraoophoron
- Gartner’s duct
All can become irritated, inflamed and form possible tumours
Where does the paramesonephric duct originate from? What structures does it open into superiorly and inferiorly?
The Hydatid of Morgani (hangs off the uterine tube)
Superiorly opens into the abdominal cavity and inferiorly makes contact with the cloaca
What is the tunica vaginalis and what forms it?
Tunica vaginalis is the pouch of serous membrane that covers the testes.
As the testis descend they drag the peritoneal membrane with them until it detaches from the peritoneum and forms the tunica vaginalis
What happens if the testis never drop? What is the name of this condition?
Body temp is too high for sperm production, the affected individual will be infertile
Cryptochordisim
What can happen if the peritoneal membrane never disconnects during testis descent?
Can cause an accumulation of fluid, hernia, etc
What are skene’s glands? Where are they and where do they come from? *include another name for them
Skene/paraurethral glands are glands located on the anterior wall of the vagina, they are the ‘female prostate’ and come from the urogenital sinus
What is the significance of the verumontanum?
Its a landmark of the prostatic urethra and has 3 openings:
- Prostatic utricle (representing the paramesonephric duct which does nothing in males)
- Two ejaculatory ducts on either side
What is the ultimate fate of the mesonephric duct?
It’s gradually absorbed into the wall of the urogenital sinus
How does cloacal partitioning occur?
The urorectal septum grows down dividing the urogenital sinus anteriorly and the anorectal canal posteriorly
What forms the genital tubercle component of external genitalia in males and females?
Males: penis
Females: clitoris