kashdoc21
Forum Senior
Topics: 52
Posts: 127
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Q. what happens to secondary oocyte when fertilization does not take place .... and how come down's synd is associated with primary oocyte arrested state n not secondary oocyte ...
Q.EPIBLAST gives rise to extraembryonic somatic n visceral mesoderm -- true ?
any hints how to memorise endo. ecto n mesoderm derivatives ?
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| lam79m
Forum Junior
Topics: 6
Posts: 43
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-If the secondary oocyte is not fertilized it stayes stuck in meiosis II without completion, to the best of my knowledge. Afterwards eliminated with the onset of menstruation due to lack of stimulation of the corpus luteum by HCG.
-The primary oocyte is stuck in meiosis I since early development, and after 40 years, the risk of trisomy 21 increases substantialy. Secondary oocyte develope from the completion of meiosis I which is first produced at the onset of puberty with the LH surge and ovulation.
Yes, the epiblast does give out the extraembryonic mesoderm at week 2.
Regarding memory aid:
http://www.medicalmnemonics.com/cgi-bin/return_br...
Though I donīt know if there are any good.
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| ManuNastai
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the epiblast gives rise to ALL of them: ecto, mezo (intr and extraembryonic) and endoderm
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| Ancylostoma
Forum Guru
Topics: 42
Posts: 636
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only thing that I can add is that oocytes are stuck in the prophase of meiosis one until ovulation, and then stuck again in the metaphase of meiosis two, until fertilization.
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