2. Development Of Reproductive Tracts Flashcards
When do male and female morphologic characteristics begin to develop?
7th week
What is the initial period of genital development called?
Indifferent stage of sexual development
What is the dilated structure at the end of the hindgut?
Cloaca - becomes urogenital sinus
What are the primordial cells?
‘Seed’ for next generation
Allocated shortly after initiation of current generation
Arise in yolk sac and migrate into retroperitoneum
What are the gonads derived from?
Mesothelium - lining posterior abdominal wall Underlying mesenchyme (embryonic connective tissue) Primordial germ cells (earliest undifferentiated sex cells)
The depression of SRY gene drives what?
Development of male (gonad, testicular hormones, internal genitalia)
What does the Mullerian duct go on to form?
Female reproductive tract
What does the wolffian duct go on to form?
Male duct system
What is the wolffian duct also known as?
Mesonephric duct
What is the Müllerian duct also known as?
Paramesonephric duct
What is released from the seminiferous tubules during development?
Mullerian-inhibiting substance to prevent Müllerian ducts developing
What can happen when development of ducts goes wrong?
Exogenous androgen released
Supports wolffian duct, but no testis so no MIH, therefore Müllerian ducts develop
What happens in an androgen-resistant male?
Androgen insensitivity syndrome
Receptors for testosterone don’t work, wolffian ducts don’t survive, but MIH present so Müllerian ducts degenerate
Describe the mesonephric duct development
First acts as duct for embryonic kidney Drains into urogenital sinus Urogenital sinus will become the bladder Duct maintained by testis Converted into vas deferens and epididymis, migrates with the testis as it descends
Describe the paramesophrenic duct development
Appear as invaginations of epithelium of urogenital ridge
Caudally - make contact with cloaca (urogenital sinus)
Cranially - open into abdominal cavity
