17. Embryology of the Reproductive System

Question 1

Primordial germ cells

Answer 1

• Exact moment of origin unknown
• Migrate from epiblast to yolk sac
• Then from yolk sac to genital ridge
• Germ cells induce development of
  
  • Genital ridges (give rise to gonads)
  • Mesonephric ducts (connecting kidney to sinus)
  • Paramesonephric ducts
• Differentiation
  
  • Gonads will develop into sex-specific structures under influence of genetic information
• Testes: develop under influence of TDF
• Uterus formed out of fusion of ductus paramesonephricus
  
  • Starts solid, develops hollow tube
• Vagina: induction by same ductus, starts as connection to sinus
• Pathology
  
  • Result of incomplete fusion, can lead to subfertility
    
    • Also: twins in 2 uteruses
• Embryonic rest
  
  • Female rests of ovarian descent
  • Ovarian and round ligament
  • Relation to inguinal canal
    
    • Comparable route to outside
    • Labia majora instead of scrotum
      
      • Round ligament in inguinal canal

Question 2

Comparable structures

Answer 2

• Glans penis with clitoris
  
  • Shaft with corpus clitoris
  • Scrotum with labia majora
  • Raphe with labia minora