Exam - Sexual Differentiation Flashcards
what does sex need
2 individuals to produce germ cells which fuse to produce an offspring
what Is carried by genes
difference/sexual dimorphism
sex chromosomes
what are the female sex chromosomes in mammals
XX
what are the male sex chromosomes in mammals
XY
what are the female sex chromosomes in birds
ZW
what are the male sex chromosomes in birds
ZZ
what are gonads during early fetal life
undifferentiated
what is embryonic sex differentiation
the formation of primordial germ cells
where do primordial germ cells form
extra-embryonic organ
where do primordial germ cells circulate
in vasculature
where do primordial germ cells migrate
through tissues
what does embryonic sex differentiation colonize
the genital ridge to form indifferent gonads
what does differentiation of the cortex turn into
the ovary or medulla into the testis
what do testis organize through
the transient expression of genes from the sex determining region Y
what factor organizes the testis
testes differentiation factor
how does the hypothalamus take part in sex differentiation
it has 2 centres with GnRH neurons
what are the 2 centres in the hypothalamus that contain GnRH neurons
tonic center
surge center
what is the tonic center responsible for
basal secretion
what is the surge center responsible for
ovulatory cycles and female behaviour
what happens to estradiol during the peritoneal period
it is released by placenta and embryonic adrenals, binds to a carrier in blood and does not enter the brain
what happens to testosterone during the perinatal period
it is released by embryo testes, diffuses into the brain and is converted to estradiol
what happens during the perinatal period if there is estradiol in the brain
the surge center is inactivated = male brain