Psychology 2040A/B Lecture Notes - Umbilical Cord, Prenatal Development, Amnion
19 Nov 2013
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Environmental influence on prenatal development from conception to birth: teratogens, environmental hazards, the mother. Period of the zygote/germinal period: conception to implantation in uterine wall: 2 weeks long. Period of the embryo: major organs formed and heart begins to beat. Period of the fetus: major organ systems function, rapid development. Grow inside out, head down. Path to implantation inner layer of blastocyst becomes embryo, outer layer forms tissues that protect and nourish embryo. Support structures of the embryo formed by outer layer: amnion: watertight sac filled with fluid from mother"s tissues. Protects organism from external environment: chorion: surrounds amnion and becomes placenta, placenta: semipermeable barrier sustaining embryo, umbilical cord. All major organs formed and some begin to function. Endoderm: becomes digestive system, lungs, urinary tract, other vital organs. Brain develops rapidly limbs develop indifferent gonad appears. Able to kick, twist not felt by mother. Movements begin in preparation for extrauterine life. Visual and auditory senses function by 6 months.
