PSY BEH 101D Lecture Notes - Lecture 6: Primitive Streak, Neural Tube, Synaptogenesis
15 Jul 2018
School
Department
Course
Professor
Document Summary
Within hours after conception, the zygote begins duplication and division. First, the 23 pairs of chromosomes duplicate, forming two complete sets of the. First cells are stem cells , able to produce every other cell and become a complete genome person. Cells from which any other specialized type of cell can form. After about the eight-cell stage, a third process, differentiation, begins depending on where they are located. Cells specialize, taking different forms and reproducing at various rates, Implantation : the process, beginning about 10 days after conception, in which the developing organism burrows into the tissue that lines the uterus, where it will be nourished. About 50 percent of natural conceptions and an even larger percentage of. E(cid:304)bryo(cid:305)ic period: (cid:265)ro(cid:304) the (cid:412)rd-(cid:417)th week in vitro conceptions never implant. Formless mass of cells takes shape and merits a new name, embryo. Begins when a thin line (called the primitive streak ) appears down the middle of.
