Animal Science 434 Reproductive Physiology" Embryogenesis of the Pituitary and Sexual Development: Part A Development of the Pituitary Gland" Infundibulum" Brain" Rathke s Pouch" Stomodeum"
Germ Cell Migration" Migration from endoderm" through mesoderm." Migration begins by the 4 week of gestation in cow and human." Fetal Kidneys" Pronephros» regresses Mesonephros» portions of reproductive tract Metenephros» Adult kindney and urinary ducts In birds the migration is via the blood stream." Development of Mesenephros and Metenephros" Jost Experiments" Paramesonephric Ducts" (Mullerian Ducts)" Mesonephric Ducts" (Wolffian Ducts)" http://www.ansci.wisc.edu/jjp1/ansci_repro/lec/lec5/ early_dev.swf Lecture - Other Files Early Dev Animation Ovary" Oviduct" Uterus" Testis" Epididymis" Vas Epidi Deferens" Seminal dymi Vesicles" s"
Sex Determination: The Jost Paradigm" Sex Determination: The Jost Paradigm" Gonadal Sex" Gonadal Sex" Gonadal Sex" Phenotypic Sex" Phenotypic Sex" Hormonal Sex" Phenotypic Sex" Single Pair of sex chromosomes» mammals, some but not all vertebrates» sea worms, fish, reptiles» invertebrates, insects, reptiles» bees, spiders Sex is environmentally determined Brain and/or Behavioral Sex" A. Drosophila Sex depends on the number of X chromosomes X or XY or XO = Male XX or XXX or XXY = Female Multiple sex chromosomes Haplodiploidy A. Drosophila Sex depends on the number of X chromosomes X or XY or XO = Male XX or XXX or XXY = Female A. Drosophila Sex depends on the number of X chromosomes X or XY or XO = Male XX or XXX or XXY = Female B. B. Human (mammals) XY or XXY or XXYY or XXXY = Male (testis) XX or XXX = Female (ovary) XO = Female with incomplete ovarian development XXY or XXYY or XXXY or XXXXY = testis but impaired sperm production Human (mammals) XY or XXY or XXYY or XXXY = Male (testis) XX or XXX = Female (ovary) XO = Female with incomplete ovarian development XXY or XXYY or XXXY or XXXXY = testis but impaired sperm production C. Conclusion The gene that controls testicular differentiation is on the Y chromosome in mammals.
Human X and Y Chromosomes" X Y The Y Chromosome" A. Region coding for testicular development Short arm of Y chromosome H-Y Antigen «no longer believed to be involved SRY «Codes for a DNA binding protein «acts as a transcription factor «Causes primary sex chord (seminiferous tubule) development Development of Sertoli Cells Anti-Mullerian Hormone production by Sertoli Cells «absence of SRY 2nd sex chords (egg nests) develop The Y Chromosome Cont." B. Other genes on the Y chromosome» Spermatogenesis» androgen production» long bone growth SRY and Birds" Birds» females ZW, males ZZ» W chromosome determines sex» SRY is found on the Z chromosome! SRY is not the only sex determining gene in animals Gonadal Sex"
Mesonephric (Wolffian Duct)" Testicular Development" Mesonephric Mesonephric " Rete Rete Mullerian Tunica " Albuginea" Undifferentiated " Sex Chords" Mullerian Tunica " Albuginea" Primary, Epithelial or" Medullary Sex Chords" Primordial germ cells (gonocytes)" Pre-Sertoli Cells" Primary Sex Chords in Fetal Testis" Hormonal Sex" Pre-Sertoli Gonocyte Wolffian Duct Cells" Nucleus" Testis" TR"
Efferent Ducts" (Vas Efferentia)" Rete Epididymis" Vas" Deferens" Tunica " Albuginea" Seminiferous" Mullerian duct" Female Development" Vas efferentia" XX Female" No TDF" Testes Determining Factor" Ovaries Develop" No" Wolffian Ducts" Regress" Ovarian Development" Primary or " Epithelial" Sex Chords" Future Ovarian" Cortex" No AMH" Mullerian ducts become" the oviducts, uterus, cervix " and part of the vagina" Epithelial" Sex Chords" Future Ovarian" Cortex"
Primordial" Follicles" Epithelial" Sex Chords" Primordial" Follicles" Ovarian" Medulla" Future Ovarian" Cortex" Secondary or Cortical Sex Chords" (egg nests)" Ovarian" Cortex" 2nd Sex Chords in Fetal Ovary" Development" of the Uterus, Cervix" and Vagina" Mullerian Fused Hymen"
Reproductive tract develops outside the! peritoneum!! Broad Ligament Development" (transverse anterior section)" Ovary" Ovary" Wolffian (Posterior Transverse Section)" XX Female" No TDF" Genital Fold" (Future Broad Ligament)" Ovaries Develop" No" No AMH" Mullerian duct" Wolffian duct" Mullerian ducts become" the oviducts, uterus, cervix " and part of the vagina" Phenotypic Sex" Mullerian
Wolffian Duct Cells" Nucleus" Testis" TR" Mullerian Dihydrotestosterone" Development of penis" scrotum and accessory " sex glands" Accessory Sex Glands* and External Genitalia Cells" Nucleus" Testis" D" 5α -" Reductase" DR" *Prostate, Cowper s Gland"