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14 Cards in this Set
- Front
- Back
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indeterminate cleavage
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results in cells that maintain the ability to develop into a complete organism
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determinate cleavage
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future pathways are determined
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When does the first cleavage or the zygote occur?
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at around 32 hours
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When is the embryo implanted in the uterus?
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At the 8-cell level, it travels and implants itself in the uterus, where it will develop into a morula next
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What are the 3 main embryo stages?
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morula, blastula, gastrula
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What are the two cell types in a blastocyst?
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trophoblast
inner cell mass A blastocyst has a fluid filled cavity called the blastocoel. The outer layer is called the trophoblast, the mass of cells protruding into othe blastocoel is the inner cell mass. |
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When does the embryo implant itself in the uterine wall?
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during blastulation, 5-8 days after fertilization. The endometrium prepares itself by thickening at the rise of progesterone.
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What are the three cell layers of a gastrula?
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ectoderm, mesoderm, endoderm
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What is the opening of a gastrula called?
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blastopore - site of human anus
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Ectoderm
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integument system (skin, hair, nails, anal canal, epithelium of nose and mouth), lens of eye, nervous system
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Endoderm
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epithelial lining of digestive and respiratory tracts (lungs), parts of the liver, pancreas, thyroid and bladder
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Mesoderm
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musculoskeletal system, circulatory system, excretory system, gonads, connective tissue throughout the body, and portions of digestive and respiratory organs.
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notochord
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developed from the mesoderm, inductive effect on the overlying ectoderm, causing it to form into the CNS and PNS
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When is an embryo a fetus
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8 weeks
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