PHYL2001 Lecture Notes - Lecture 15: H-Y Antigen, Testicle, Gonadal Ridge
Document Summary
In absence of hy antigen, get female system, even if there is a y chromosome present. Although the male and female external genitalia develop from the same undifferentiated embryonic tissue, this is not the case with the reproductive tracts. Two primitive duct systems develop in all embryos the wolffian ducts the m llerian ducts . In females the reproductive tract develops from the wolffian ducts and the m llerian ducts degenerate, the m llerian ducts differentiate into the reproductive tract and the wolffian ducts regress. Because both duct systems are present before sexual differentiation occurs, the early embryo has the potential to develop either a male or a female reproductive tract. Wolffian duct system: m llerian inhibiting factor (anti-m llerian hormone- A hormone released by the placenta, human chorionic gonadotropin, is the stimulus for this early testicular secretion. Labia: note that the undifferentiated embryonic reproductive tissue passively develops into a female structure unless actively acted on by masculinizing factors.
