BIOL 030 Lecture Notes - Lecture 4: Congenital Disorder, Somite, Embryogenesis
17 May 2020
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Pre embryonic period zygote through day 16: cleavage cell division, implantation embeds in endometrium of uterus, embryogenesis cells migrate & differentiate into 3 layers: ectoderm, mesoderm, endoderm. Embryonic period day 17 until end of week 8, germ layers develop into the rudiments of all organ systems. Fetal period week 9 through birth, organs grow & become capable of function. Table 3. 1 major derivatives marjeb, table 4. 2 book. Ectoderm: epidermis including glands, hair & nails, brain & spinal cord, neural crest. Endoderm: inner lining & glands of digestive tube. Birth defects 3% of all newborns have congenital anomalies (up to 6% by 1 year old) Prior to week 3 result in sp ab from 50-75% of all fertilized ova. Microscopic appearance single layer of flat cells. Locations lungs, inside heart and blood vessels. Functions rapid diffusion, reduces friction, secretion of serous fluid. Microscopic appearance small cube or wedge shape cells, single layer.
