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Animal Science 434 Reproductive Physiology

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Presentation on theme: "Animal Science 434 Reproductive Physiology"— Presentation transcript:

1 Animal Science 434 Reproductive Physiology
Embryogenesis of the Pituitary and Sexual Development: Part A

2 Development of the Pituitary Gland
Infundibulum Brain Rathke’s Pouch Stomodeum

3

4

5

6

7 Germ Cell Migration Migration begins by the 4 week of gestation in cow and human.

8 Migration from endoderm
through mesoderm.

9 In birds the migration is via the blood stream.

10 Fetal Kidneys Pronephros Mesonephros Metenephros regresses
portions of reproductive tract Metenephros Adult kindney and urinary ducts

11 Development of Mesenephros and Metenephros
Lecture - Other Files – Early Dev Animation

12 Paramesonephric Ducts
Jost Experiments Mesonephric Ducts (Wolffian Ducts) Paramesonephric Ducts (Mullerian Ducts) Testis Ovary Epididymis Oviduct Epididymis Vas Deferens Seminal Vesicles Uterus

13 Sex Determination: The Jost Paradigm
Chromosomal Sex Gonadal Sex Phenotypic Sex

14 Sex Determination: The Jost Paradigm
Chromosomal Sex Gonadal Sex Phenotypic Sex Chromosomal Sex Gonadal Sex Phenotypic Sex Hormonal Sex Brain and/or Behavioral Sex

15 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

16 Chromosomal Sex A. Drosophila
Sex depends on the number of X chromosomes X or XY or XO = Male XX or XXX or XXY = Female

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 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

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 C. Conclusion The gene that controls testicular differentiation is on the Y chromosome in mammals.

19 Human X and Y Chromosomes

20 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

21 B. Other genes on the Y chromosome
The Y Chromosome Cont. B. Other genes on the Y chromosome Spermatogenesis androgen production long bone growth

22 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

23 Gonadal Sex

24 Testis Determining Factor
XY Male Testis Determining Factor (SRY gene product) Testes develop

25 Testicular Development
Mesonephric Duct (Wolffian Duct) Mesonephric Tubules Rete Tubules Mullerian Duct Tunica Albuginea Undifferentiated Sex Chords

26 Mesonephric Tubules Wolffian Duct Tunica Albuginea
Rete Tubules Wolffian Duct Primary, Epithelial or Medullary Sex Chords Primordial germ cells (gonocytes) Pre-Sertoli Cells Mullerian Duct Tunica Albuginea

27 Primary Sex Chords in Fetal Testis
Pre-Sertoli Gonocyte

28 Hormonal Sex

29 Testis Determining Factor
XY Male Testis Determining Factor (SRY gene product) Testes develop Sertoli cells secrete anti-mullerian hormone (AMH) AMH causes leydig cells to differentiate Testosterone Development of male duct system

30 Wolffian Duct Cells Nucleus T Testis T TR

31 Efferent Ducts Seminiferous Tubules Vas Deferens Tunica Albuginea
(Vas Efferentia) Rete Tubules Epididymis Seminiferous Tubules Vas Deferens Tunica Albuginea

32 Testis Determining Factor
XY Male 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

33 Vas efferentia

34 Testes Determining Factor
Female Development No TDF Testes Determining Factor XX Female Ovaries Develop No Testosterone No AMH Mullerian ducts become the oviducts, uterus, cervix and part of the vagina Wolffian Ducts Regress

35 Ovarian Development Regressing Tubules Mullerian Duct Primary or
Epithelial Sex Chords Future Ovarian Cortex Wolffian Duct

36 Regressing Tubules Mullerian Duct Regressing Epithelial Sex Chords Future Ovarian Cortex Regressing Wolffian Duct

37 Secondary or Cortical Sex Chords
Regressing Tubules Primordial Follicles Mullerian Duct Regressing Epithelial Sex Chords Future Ovarian Cortex Regressing Wolffian Duct Secondary or Cortical Sex Chords (egg nests)

38 Primordial Follicles Mullerian Duct Ovarian Medulla Ovarian Cortex Regressing Wolffian Duct

39 2nd Sex Chords in Fetal Ovary

40 Development of the Uterus, Cervix and Vagina
Mullerian Duct

41 Fused Mullerian Duct Hymen

42

43 Broad Ligament Development (transverse anterior section)
Reproductive tract develops outside the peritoneum! Broad Ligament Development (transverse anterior section) Ovary Regressing Wolffian Duct Mullerian Duct

44 Ovary Regressing Wolffian Duct Mullerian Duct

45 (Posterior Transverse Section) (Future Broad Ligament)
Genital Fold (Future Broad Ligament) Regressing Wolffian Duct Mullerian Duct

46 XX Female XY Male No TDF Ovaries Develop No No AMH Testosterone
Testis Determining Factor (SRY gene product) No TDF XX Female XY Male Testes develop Ovaries Develop No Testosterone No AMH Sertoli cells secrete anti-mullerian hormone (AMH) AMH causes leydig cells to differentiate Degeneration of Mullerian duct Degeneration of Wolffian duct Mullerian ducts become the oviducts, uterus, cervix and part of the vagina Testosterone Development of male duct system

47 Phenotypic Sex

48 XY Male 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

49 XY Male 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 Dihydrotestosterone Development of penis scrotum and accessory sex glands Development of male duct system

50 Wolffian Duct Cells Nucleus T Testis T TR

51 Accessory Sex Glands* and External Genitalia Cells
Nucleus T Testis T D DR 5- Reductase *Prostate, Cowper’s Gland


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