CAS PS 241 Lecture Notes - Lecture 7: List Of Greyhawk Characters, Radiography, Fetal Alcohol Spectrum Disorder
2 Oct 2016
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Document Summary
Zygote is formed when a sperm and egg meet. This period ends at implantation in the uterine wall. Implantation: the blastocyst penetrates blood vessels in the uterine wall to provide nutrients to the blastocyst, organism is now dependent on mother. The germinal/zygotic period is a very fragile time, 20-60% fail to implant (miscarriage) This is probably an underestimate because it only accounts for known pregnancies during the zygotic period, many women don"t know yet. Study shows the number could be as high as 78% Rapid mitosis, 2 million% increase in size. Ectoderm: outer layer, skin, nails, hair, nervous system. This period is most vulnerable to environmental influence. Amnion: amniotic sac, protects baby and provides temperature regulation. Nutrients from mom in, waste from baby out. Two arteries pull blood out to get rid of waste and a vein pulls nutrients in. Ex: heart develops before fingers of an inch, has arm and leg stumps, hands begin.
