Development of the Male and Female reproductive tracts Flashcards
What is the default developmental state for the reproductive system?
Female (lack of Y chromosome and its gene products - form an ovary)
What are the three tissue sources from which the gonads (testicles and ovaries) develop?
- Gonadal ridge (raised region of intermediate mesoderm)
- Mesodermal epithelium (covers the future post abdo wall)
- Primordial germ cells (induce develop of indifferent gonad)
In a developing male, expression of which protein causes the indifferent gonad to become a testicle?
Testis Determining Factor (TDF) - gene on the Y chromosome.
Testosterone secretion by week 8 influences further sexual differentiation of the genitalia
What is Androgen insensitivity syndrome (AIS)?
Results in a genetic male with normal female appearance
Testicles are present and the vagina ends as blind poucha
How do the gonads descend to their adult position?
- Gubernaculum - guides descent of gonads
- Processus vaginalis - forms the inguinal canal
Both structure guide testicle through inguinal canal
What are the two conditions that can be caused by maldescent of the testes?
1.Cryptorchidism (surgical intervention?)
Most often located in inguinal canal (IC)
Many undescended testes appear by 3 months post birth
Inc risk of testicular cancer
2.Ectopic testicle
Testicle transverses IC but ends up not in the scrotum (post abdo wall)
In the female, what normally happen to the processus vaginalis? What happens if it persists?
In females, the processus vaginalis is small and normally regresses.
It’s persistence is known as a persistent processus or the peritoneum (canal of Nuck)
In females, where do the descent of the ovaries stop?
Ovaries stop in the pelvic cavity at the broad ligament (double layer peritoneal fold covering the uterus and uterine tubes - mesentery)
What happens to the female gubernaculum? (hint - persists and attaches to…)
Persists and attaches from the:
- Ovary to uterus (ovarian ligament)
- Uterus to labia (round ligament of uterus)
Why is the round ligament important to consider as a potential pathway for metastatic spread of cancer?
Because it contains lymphatics and vasculature
What are the two pairs of genital ducts that develop in males and female?
Mesonephric (Wolffian) ducts - develop in Male (M)
Paramesonephric (Mullerian) ducts - develop in female
What happens to the mesonephric duct in males and females?
Males: Testosterone production drives the development of the mesonephric duct (week 8) forming the epididymis, ductus deferens, ejaculatory duct and seminal vesicles.
Females: degenerates spontaneously in the absence of testosterone
What happens to the paramesonephric duct in males and females?
Males: Antimullerian hormone production by testicular sertoli cells causes paramesonephric duct regression (week 6-7)
Females: Persists and further develop in the presence of antimullerian hormone - forms the uterine tubes and join in the inferior midline to form the uterus and upper vagina
In males, what is the remnant of the paramesonephric duct called?
Appendix of testicle (can be seen in an ultrasound)
What can happen as a result of uterine and vaginal malformations?
Primary amenorrhoea, subfertility or problematic pregnancy