Sexual Differentiation In Utero Flashcards
Oocytes
Highly specialized cells whose differentiation must be reversed following fertilization so that growing embryo can differentiate into different tissues
HPG axis
Hypothalamic pituitary gonadal axis
- set of organs that regulates reproduction
Totipotent
Cells are able to differentiate into any type of embryonic (body) or extra-embryonic (placental) cells
Trophectoderm (TE)
Multi potent cells capable of differentiation into any type of cells within a certain lineage
-placental lineage
Inner cell mass (ICM)
Pluripotent cells - can differentiate into any type of cells in embryo
-differentiates into epiblast and hypoblast
Epigenetics
Determines differentiation
- markers that turn genes on or off depending on external influence
Gastrulation
Formation of germ layers from one-dimensional layer of cells
- develops bilaminar disc into trilaminar
Ectoderm
Differentiates into NS, skin, hair and external genitalia
Mesoderm
Develops between epiblast and hypoblast and gives rise to muscles, skeleton, CVS, and urogenital system
Primordial Germ Cells (PCG)
Form mesoderm colonize gonadal ridge and differentiate it to male or female
-colonization occurs early in development, preceding differentiation
Gonadal ridge
Formed from mesoderm, medial to mesonephros (embryonic kidneys)
Development of Kidneys
- Mesonephros function as temporary kidney, drained by mesonephric tubules that merge into larger mesoneohric/wolffian ducts
- Metanephros (real kidney) increase in size while mesonephros lose function and paramesoneohric/mullerian ducts grow parallel to mesonephric ducts
- Gonads and metanephros enlarge and metanephric duct develops into the ureter
- Metanephros become fully functional and gonads enlarge, mesonephros have regressed
