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A&P CH20 key terms
A&P CH20 Pregnancy, Growth, and Development
Term | Definition |
---|---|
amnion | an extraembryonic membrane that encircles a developing fetus and contains amniotic fluid |
chorion | extraembryonic membrane that forms the outermost covering around a fetus and contributes to formation of the placenta |
cleavage | the early successive divisions of blastocyst cells into smaller and smaller cells |
embryo | a prenatal stage of development after germ layers form but before rudiments of all organs are present |
fertilization | the union of an egg cell and a sperm cell |
fetus | a human embryo after eight weeks of development |
gastrula | an embryo at the stage following the blastula, when it is a hollow cup-shaped structure having three layers of cells. |
neonatal period | the first four weeks of life |
placenta | structure that attaches the fetus to the uterine wall, providing for delivery of nutrients to and removal of wastes from the fetus |
postnatal period | the period after birth |
prenatal period | the period before birth |
primary germ layers | three layers of embryonic cells that develop into specific tissues and organs, ectoderm, mesoderm, and endoderm |
umbilical cord | cordlike structure that connects the fetus to the placenta |
zygote | cell produced when an egg and a sperm fuse; fertilized egg |