BIO 121 Lecture Notes - Lecture 28: Inner Cell Mass, Sodium-Potassium Alloy, Fertilisation
24 Jul 2020
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Inner cell mass gives rise to baby. Aerobic glycolysis prod lactate in presence of oxygen: only blastocysts & cancers do this. Fertilisation takes place in ampulla sperm enters & completion of second meiotic division & extrusion of 2nd polar body sperm head & female chromosomes form membrane around each other (pronuclei) which haven"t fused yet. Early embryos use pyruvate & blastocyst onward use glucose (energy sources) Cleavage slow 1st one prod developmentally equivalent blastomeres. Little/no yolk b/c located in fallopian tubes where mother can prov most nutrients. Compacted morula is 8-cell mass that has formed epithelium (soccer ball vs bag of oranges) Cells smaller /w ea division restore nucleus:cytoplasm ratio. Embryonic genome activation (gradual process) pre-stored mrna destroyed & pre- stored proteins still function. Produces polarity defines inside & outside of cell. Ion channels present creates conc gradient fluid movement which creates cavitation. Some cells enclosed in inner compartment of morula.
