Term
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Definition
| First 38 weeks of human development (pre-embryonic, embryonic, and fetal) |
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Term
| Events of the Pre-Embyronic Period |
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Definition
| weeks 1-2: fertilization (day 1), zygote, morula (16 cells), blastocyst (100 cells), and implantation |
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Term
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Definition
| 100 cell organism of pre-embryonic period, has an inner cell mass called the embryoblast (becomes embryo) and an outer cell mass called the trophoblast (becomes chorion) |
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Term
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Definition
| The trophoblast divides into two layers--the cytotrophoblast (inner layer) and the syncytiotrophoblast (other layer/thick), which burrows into the functional layer of the endometrium and brings the blastocyst with it. These layers help to create the chorion, which creates the fetal part of the placenta |
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Term
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Definition
| divides into two layers to form the bilaminar disc--the epiblast and the hypoblast |
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Term
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Definition
| top layer of bilaminar disc--forms the embryo and the amnion |
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Term
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Definition
| bottom layer of the bilaminar disc--forms the yolk sack |
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Term
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Definition
| weeks 3-8, primitive streak, gastrulation, folding, neurogensis, and organogensis |
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Term
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Definition
| epiblast cells invaginate through thte primitive streak towards the hypoblast--invaginating lays down endoderm and mesoderm; remaining cells are ectoderm |
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Term
| Name the three germ layers and what they form |
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Definition
| Ectoderm (skin and nervous tissue), mesoderm (muscle tissue, heart, kidneys, reproductive organs, connective tissue, and endoderm (digestive and respiratory systems) |
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Term
| What are the two types of Body Folding? When do they Occur? |
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Definition
| The embryonic stage, transverse folding and cephalocaudal folding |
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Term
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Definition
| The notochord (a tube of mesoderm) induces the epiderm to develop the neural tube |
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Term
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Definition
| Embryonic period, most organ systems have developed by week 8, but not life sustainable yet (embryonic period) |
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Term
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Definition
| Weeks 9-38, respiratory is the last to develop, this is the maturation stage of the organs |
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Term
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Definition
| 3% of babies; 50% are by unknown causes, usually responsible for miscarriages, can be caused by teratogens |
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Term
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Definition
| anything that causes a birth defect; FAS is #1 cause of mental retardation in USA; accutane causes mental disability in 50% |
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