Sexual Differentiation and Disorders Flashcards
What is the definition of sexual determination?
β Genetically controlled process dependent on the switch on the Y chromosome
What is sexual differentiation?
β The process by which internal and external genitalia develop as male or female
What does gender depend on?
β A switch gene in the Y chromosome
What is genotypic sex?
β XY
β XX
What is gonadal sex?
β Testes
β Ovaries
What is phenotypic sex?
β outward appearance
What is Legal sex?
β Passport/birth certificate
What is gender identity?
β How you feel / not always the same as phenotypic
What is the first event that occurs that determines sex?
β Genetic signal which then form testes or ovaries
What gene creates the testes?
β The SRY gene
In the absence of the Y chromosome what develops?
β Ovaries
What does SRY mean?
β Sex determining region
When does the SRY region switch on and what happens when it is switched on?
β During embryo development in > week 7
β makes gonad into testis
What two types of cells are in the testis?
β Sertoli cells
β Leydig cells
What do Sertoli cells make?
β Produce anti mullerian hormone
What do Leydig cells make?
β Testosterone
What is SRY?
β A transcription factor that causes self transcription
What happens after fertilization (gonads)?
β A pair of gonads develop which are bipotential
What is the precursor of gonads derived from?
β Somatic common mesenchymal tissue precursors called genital ridge primordia
What do the genital ridges become?
β Ovaries or testes
What does the Mullerian duct become?
β Uterus
β Uterine tubes
β Upper third of vagina
What does the Wolffian duct become?
β Vas deferens
β Prostate
What are the 3 types of cells that invade the genital ridge?
β Primordial germ cells
β Primitive sex cords
β Mesonephric cells
What do primordial germ cells become?
β Sperm or oocytes
What do primitive sex cords become?
β Sertoli cells
β or Granulosa cells
What do mesonephric cells become?
β Leydig cells
β Theca cells
Describe primordial germ cell migration
β Small clusters of PGC cells in the epithelium of the yolk sac expand at 3 weeks
β Migrate to the connective tissue of the hindgut to the region of the developing kidney and onto the genital ridge
Describe what happens to primitive sex cords in the male
βSRY expression
βPenetrate the medullary mesenchyme and surround the primordial germ cells to form testis cords
βEventually become sertoli cells which express anti Mullerian hormone