PSY 100 Lecture Notes - Lecture 5: Organogenesis, Psy, Umbilical Cord
1 Dec 2020
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Document Summary
Period of prenatal development that occurs from two to eight weeks (till the first two months) after conception; rate of cell differentiating intensifies, support systems for the cells form, and organs appear (organogenesis) The blastocyst attaches to the uterine wall. The mass of cells is now called an embryo and 3 layers of cells form; Mesoderm: the inner layer of cells, which develop into the digestive and respiratory systems the middle layer of cells, which develop into the circulatory system, bones, muscles, excretory system, and reproductive system. Ectoderm: the outermost layer of cells, which develop into the nervous system and brain, sensory receptors (ears, nose and eyes), and skin parts (hair and nails) Every part of the body eventually develops from these 3 layers. Embryo support systems: three prenatal life-support systems develop directly from the fertilized egg (not the mother); A bag/envelope that contains a clear fluid (amniotic fluid) in which the developing embryo floats.
