Embryo- Genital development Flashcards
what embryonic layer gives rise to the genital system?
Intermediate mesoderm
what layer of the mesoderm becomes retroperitoneal?
Intermediate mesoderm
what does the intermediate mesoderm form?
Bilateral urogenital ridges
what are the 2 urogenital ridges?
Nephrogenic cord
Gonadal ridge
which portion of the urogenital ridge is lateral?
Nephrogenic cord
which portion of the urogenital ridge is medial?
Gonadal ridge
during what week do we see sex differentiation?
Week 7
When is the “indifferent stage”?
Weeks 1-6
what type of cells migrate to gonadal ridges?
Primordial germ cells
What happens in week 5?
Intermediate mesoderm thickens to form gonadal ridge
Mesothelial cord cells form solid….
form solid gonadal cords that sink into underlying mesenchyme
what is SRY?
“sex determining region of the Y chromosome”
What is TDF?
Testes-determining factor
what are Leydig cells?
Leydig cells (stromal CT cells) -develop from mesenchyme of gonadal ridge.
-Produce: TESTOSTERONE
What are Sertoli cells?
- “caretakers” of primordial germ cells
- develop from gonadal cord cells
What do the sertoli cells form?
1) Seminiferous tubules
2) Rete testes
which cell type surrounds the primordial germ cells?
Leydig cells (interstitial cells)
which cells develop in close proximity to the PGCs? (primordial germ cells)
Sertoli cells
what signals male genital development?
Testosterone
which cells produce this?
what does the mesonephric duct form
ductus deferens
Epididymis
(mesonephric tubules form efferent tubules)
Superior end of mesonephric duct forms what?
Epididymis
Mesonephric tubules form what?
efferent ductules
what induces mesonephric duct to form male genital ducts?
Testosterone
Caudal ends of mesonephric ducts develop into what?
1) seminal vesicles
2) Ejaculatory ducts
what are ALL the structures that are developed from the Mesonephric ducts?
- Epididymis
- Ductus deferens
- Seminal Vesicle
- Ejaculatory duct
the gonadal cords form what in males?
- Seminiferous tubules
- Retes testes
MIH (Mullerian Ducts regress) is produced by what?
Sertoli cells
what does MIH cause?
causes the mullerian ducts to degrade/regress
what is the remnant of the Mullerian duct in men?
the Appendix testes
the prostate and bulbouretheral glands are endodermal outgrowths from what
Urogenital sinus
where does the gubernaculum extend?
from the gonad to the labioscrotal swelling (future scrotal sac)
what is the shortening of the gubernaculum responsible for?
pulls the testis, ductus deferens, and testicular vessels downward through the abdominal wall
name the 3 layers of the scrotum
- Internal spermatic fascia
- Cremasteric muscle
- External spermatic fascia
what layer of the scrotum is formed from the external oblique aponeurosis?
External spermatic fascia
Congenital inguinal hernia-
Patent processus vaginalis
what leads to development of fluid-filled cysts in the scrotum?
Hydrocoele
What is cryptorchidism?
failure of the testes do descend
which 2 genetic factors are females lacking?
- No SRY
- No TDF
what do stromal cells of the ovary develop from?
Mesenchyme of gonadal ridge
what are follicular cells?
what do they develop from?
“caretakers” of PGCs
develop from gonadal cord cells
what cell type surrounds the PGCs
also form ovarian follicles
Follicular cells
what does a lack of testosterone cause?
Mesonephric duct regression
What does a lack of MIH lead to
continued growth & development of mullein ducts
whats another name for mullein ducts?
paramesophrenic ducts
The Müllerian ducts will form what?
The Müllerian ducts will form the uterine tubes, uterus, and superior vagina
what is formed by The cranial ends of the Müllerian ducts?
uterine tubes
what is formed by the uterovaginal primordium?
forms uterus and superior vagina
what fuses to give the uterovaginal primordium?
caudal ends of mullein ducts
The uterovaginal primordium comes into contact with the dorsal wall of the urogenital sinus and forms what?
Sinovaginal bulb
what is the vaginal plate?
Sinovaginal bulbs separating from the urogenital sinuses
-fuse with uterovaginal primordium
what forms the inferior vagina?
urogenital sinus (NOT mullerian ducts)
The greater vestibular glands, urethral glands, and paraurethral glands are all from what structure?
urogenital sinus
Labioscrotal swellings in females
- Fuse posteriorly and anteriorly
- Unfused portions become labia majora
Urethral folds in females
remain unfused as labia minora
Urethral folds in males
Fold under ventrally + fuse to form penile shaft
Labioscrotal swellings in men
Fuse at midline to form the scrotum
