HHP 3105 Lecture Notes - Lecture 2: Yolk Sac, Amniotic Sac, Prenatal Development
12 Oct 2018
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Embryology: study of the origin and development of single individual, prenatal period, embryonic period: first 8 weeks, fetal period: remaining 30 weeks. In the first 8 weeks organs form three primary germ layers: the embryonic period, week 1 - from zygote to blastocyst, conception: in lateral third of uterine tube. Somite and intermediate mesoderm comes from this: ectoderm: cells left at surface and don"t migrate inward. Somites are the first evidence of body segments: vertebrae, ribs, and axial muscles, paraxial mesoderm. Surfactant is a detergent that breaks up water tension: without this the lungs collapse, eighth and ninth months. Fetus usually rotates so head is pointed down toward cervix: tissue: a group of closely associated cells that perform related functions and are similar in cell type. Four basic types: epithelial (covering/lining), connective (support), muscle (movement), and nervous (control: wherever you find epithelial tissue you almost always find connective tissue.
