Animal Science 434 Reproductive Physiology Lec 5: Embryogenesis
of the Pituitary and Sexual Development Slide 2 Development of the
Pituitary Gland Stomodeum Rathkes Pouch Infundibulum Brain Slide 3
Slide 4 Slide 5 Slide 6 Slide 7 Migration begins by the 4 week of
gestation in cow and human. Germ Cell Migration Slide 8 Migration
from endoderm through mesoderm. Slide 9 In birds the migration is
via the blood stream. Slide 10 Fetal Kidneys Pronephros regresses
Mesonephros portions of reproductive tract Metenephros Adult
kindney and urinary ducts Slide 11 Development of Mesenephros and
Metenephros Slide 12 Early Development Flash Movie
http://www.ansci.wisc.edu/jjp1/as434/powerpoint/fa08/early_dev.swf
Requires the free flash player which can be downloaded from:
www.adobe.com Slide 13 Jost Experiments Mesonephric Ducts (Wolffian
Ducts) Mesonephric Ducts (Wolffian Ducts) Paramesonephric Ducts
(Mullerian Ducts) Testis Epidi dymi s Vas Deferens Seminal Vesicles
Ovary Oviduct Uterus Slide 14 Sex Determination: The Jost Paradigm
Chromosomal Sex Gonadal Sex Phenotypic Sex Slide 15 Sex
Determination: The Jost Paradigm Chromosomal Sex Gonadal Sex
Phenotypic Sex Chromosomal Sex Gonadal Sex Phenotypic Sex Hormonal
Sex Brain and/or Behavioral Sex Slide 16 Chromosomal Sex Single
Pair of sex chromosomes mammals, some but not all vertebrates Sex
is environmentally determined sea worms, fish, reptiles Multiple
sex chromosomes invertebrates, insects, reptiles Haplodiploidy
bees, spiders Single Pair of sex chromosomes mammals, some but not
all vertebrates Sex is environmentally determined sea worms, fish,
reptiles Multiple sex chromosomes invertebrates, insects, reptiles
Haplodiploidy bees, spiders Slide 17 Chromosomal Sex A. Drosophila
Sex depends on the number of X chromosomes X or XY or XO = Male XX
or XXX or XXY = Female Slide 18 Chromosomal Sex A. Drosophila Sex
depends on the number of X chromosomes X or XY or XO = Male XX or
XXX or XXY = Female 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 Slide 19 Chromosomal Sex A.
Drosophila Sex depends on the number of X chromosomes X or XY or XO
= Male XX or XXX or XXY = Female 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 C. Conclusion The gene that
controls testicular differentiation is on the Y chromosome in
mammals. Slide 20 Human X and Y Chromosomes Y X Slide 21 The Y
Chromosome A. Region coding for testicular development 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 Short arm of Y chromosome Slide
22 The Y Chromosome Cont. B. Other genes on the Y chromosome
Spermatogenesis androgen production long bone growth Slide 23 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 Slide 24 Gonadal Sex Slide 25 Testis
Determining Factor (SRY gene product) XY Male Testes develop Slide
26 Rete Tubules Undifferentiated Sex Chords Mullerian Duct
Mesonephric Duct (Wolffian Duct) Tunica Albuginea Mesonephric
Tubules Testicular Development Slide 27 Rete Tubules Primary,
Epithelial or Medullary Sex Chords Primordial germ cells
(gonocytes) Pre-Sertoli Cells Mullerian Duct Wolffian Duct Tunica
Albuginea Mesonephric Tubules Slide 28 Primary Sex Chords in Fetal
Testis Gonocyte Pre-Sertoli Slide 29 Hormonal Sex Slide 30 Testis
Determining Factor (SRY gene product) Testes develop XY Male
Sertoli cells secrete anti-mullerian hormone (AMH) AMH causes
leydig cells to differentiate Testosterone Development of male duct
system Slide 31 Testis T T Nucleus TR Wolffian Duct Cells Slide 32
Rete Tubules Seminiferous Tubules Vas Deferens Tunica Albuginea
Efferent Ducts (Vas Efferentia) Epididymis Slide 33 Testis
Determining Factor (SRY gene product) Testes develop XY Male
Sertoli cells secrete anti-mullerian hormone (AMH) AMH causes
leydig cells to differentiate Testosterone Development of male duct
system Degeneration of Mullerian duct Slide 34 Vas efferentia Slide
35 Female Development XX Female No TDF Ovaries Develop No AMH
Mullerian ducts become the oviducts, uterus, cervix and part of the
vagina Testes Determining Factor No Testosterone Wolffian Ducts
Regress Slide 36 Mullerian Duct Primary or Epithelial Sex Chords
Wolffian Duct Regressing Tubules Future Ovarian Cortex Ovarian
Development Slide 37 Mullerian Duct Regressing Epithelial Sex
Chords Regressing Wolffian Duct Regressing Tubules Future Ovarian
Cortex Slide 38 Mullerian Duct Regressing Epithelial Sex Chords
Regressing Wolffian Duct Regressing Tubules Future Ovarian Cortex
Primordial Follicles Secondary or Cortical Sex Chords (egg nests)
Slide 39 Mullerian Duct Regressing Wolffian Duct Ovarian Cortex
Primordial Follicles Ovarian Medulla Slide 40 2nd Sex Chords in
Fetal Ovary Slide 41 Development of the Uterus, Cervix and Vagina
Mullerian Duct Slide 42 Fused Mullerian Duct Hymen Slide 43 Slide
44 Ovary Regressing Wolffian Duct Mullerian Duct Broad Ligament
Development (transverse anterior section) Reproductive tract
develops outside the peritoneum! Slide 45 Ovary Regressing Wolffian
Duct Mullerian Duct Slide 46 Regressing Wolffian Duct Mullerian
Duct Genital Fold (Future Broad Ligament) (Posterior Transverse
Section) Slide 47 Testis Determining Factor (SRY gene product)
Testes develop Sertoli cells secrete anti-mullerian hormone (AMH)
AMH causes leydig cells to differentiate Degeneration of Mullerian
duct Testosterone Development of male duct system XY Male No TDF
Ovaries Develop No AMH Mullerian ducts become the oviducts, uterus,
cervix and part of the vagina XX Female No Testosterone
Degeneration of Wolffian duct Slide 48 Phenotypic Sex Slide 49
Testis Determining Factor (SRY gene product) Testes develop Sertoli
cells secrete anti-mullerian hormone (AMH) AMH causes leydig cells
to differentiate Degeneration of Mullerian Duct Testosterone
Development of male duct system XY Male Slide 50 Testis Determining
Factor (SRY gene product) Testes develop Sertoli cells secrete
anti-mullerian hormone (AMH) AMH causes leydig cells to
differentiate Degeneration of Mullerian Duct Testosterone
Development of male duct system XY Male Dihydrotestosterone
Development of penis scrotum and accessory sex glands Slide 51
Testis T T Nucleus TR Wolffian Duct Cells Slide 52 Testis T T 5 -
Reductase D Nucleus DR Accessory Sex Glands * and External
Genitalia Cells * Prostate, Cowpers Gland
