Human Development – Lecture 15 -- Development of
the Reproductive System
Gonads;
Sex determination (XX or XY) occurs at fertilization.
Gonads develop in 7th week
Before 7th week;
o Development of genital ridges
o Migration of primordial germ cells (PGC) from yolk sac to the
genital ridges (4-6 week)
• Exact time and place of development PGC
unknown, probably from epiblast to yolk sac.
o Development of indifferent gonads, induced by
PGC’s (same for male and female)
Around genital ridge mesonephros (excretory organ like
kidney) in it mesonephros duct (Wolffian)
Behind mesonephros duct is paramesonephric duct
(Mullerian)
o In male; they are lost
o In female; develop to from the uterine tubes, uterus,
cervic (neck of uterus) and upper 2/3 of vagina
Development of testis; 44 + XY
o Medullary cords develop (is inside the gonad)
o No cortical cords
o Thick tunica albuginea
Mesonpheric duct becomes ductus deference
Mesonephric tubules become ductuli efferentes
Presence of SRY gene on Y chromosome.
Primordial gonads differentiate into
o Sustentacular cells/Sertoli cells (inside);
• Mullerian – Inhibiting substance (MIS);
Mullerian ducts; regression
o Intestital cells/Lydig cells (outside);
• Testesteron
Wollfian ducts; transformation to epididymis, vas deference,
seminal vesicles and ejaculatory duct
• Dihydrotestosteron formed from testosterone
Development of penis, scrotum and prostate
the Reproductive System
Gonads;
Sex determination (XX or XY) occurs at fertilization.
Gonads develop in 7th week
Before 7th week;
o Development of genital ridges
o Migration of primordial germ cells (PGC) from yolk sac to the
genital ridges (4-6 week)
• Exact time and place of development PGC
unknown, probably from epiblast to yolk sac.
o Development of indifferent gonads, induced by
PGC’s (same for male and female)
Around genital ridge mesonephros (excretory organ like
kidney) in it mesonephros duct (Wolffian)
Behind mesonephros duct is paramesonephric duct
(Mullerian)
o In male; they are lost
o In female; develop to from the uterine tubes, uterus,
cervic (neck of uterus) and upper 2/3 of vagina
Development of testis; 44 + XY
o Medullary cords develop (is inside the gonad)
o No cortical cords
o Thick tunica albuginea
Mesonpheric duct becomes ductus deference
Mesonephric tubules become ductuli efferentes
Presence of SRY gene on Y chromosome.
Primordial gonads differentiate into
o Sustentacular cells/Sertoli cells (inside);
• Mullerian – Inhibiting substance (MIS);
Mullerian ducts; regression
o Intestital cells/Lydig cells (outside);
• Testesteron
Wollfian ducts; transformation to epididymis, vas deference,
seminal vesicles and ejaculatory duct
• Dihydrotestosteron formed from testosterone
Development of penis, scrotum and prostate
