ANHB1101 Lecture Notes - Lecture 11: Neural Tube, Blastocyst, Gastrulation
12 Jul 2018
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Embryogenesis: understand the basic principles of embryological terminology. Pregnancy overview: lasts 266 days from the time of fertilization. It is(cid:374)"t possi(cid:271)le to pi(cid:374)poi(cid:374)t the exa(cid:272)t ti(cid:373)e whe(cid:374) fertilizatio(cid:374) o(cid:272)(cid:272)urred so we take it back from when the last period was: divided into trimesters. 1st = point of fertilization up to 12 weeks, embryological period, vulnerable time (malformations. 2nd = rapid growth, fetal period, up to 24 weeks. *** remember f for four, folding, formation of placenta mechanisms in embryogenesis: cell division- mitosis. Initiation of cleavage (mitosis)> formation of 2 cell embryo: describe cleavage, blastocyst formation and the process of implantation. Fluid filled cavity= blastocoele (begins to form at 4. 5 days) Trophoblast- forms embryonic part of placenta (troph means to nourish) Inner cell mass forms the embryo: blastocyst hatching> must hatch from zona pelluica to implant into uterus because the zona pellucida prevents implantation from occurring.
