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15 Cards in this Set
- Front
- Back
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umbilical veins
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PAIRED vessels that deliver nutrient/O2-rich blood from the placenta to the embryo
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vitelline veins
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Drain the yolk sack
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anterior & posterior cardinal veins
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Return venous blood from the anterior and posterior parts of the embryo, respectively.
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sinus venosus
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Posterior chamber of the heart that receives venous blood
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dorsal aorti
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PAIRED vessels that receive blood from the aortic arches and distribute it to the cranial and caudal ends of the embryo
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segmental arteries
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Supply posterior segments of the embryo
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umbilical arteries
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PAIRED vessels that distribute blood back to the placenta for reoxygenation.
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Why is cardiovascular system the first system to develop?
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The embryo is growing so fast that simple diffusion from placenta to embryo is not sufficient to supply O2 and nutrients to its tissues. Circulation develops to meet these requirements.
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What day does the heart appear? What day does it begin to beat?
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Appears at day 18.
Begins to beat at day 21. |
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Shape of embryo at day 18?
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Flat disk
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3 germ layers?
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1. ectoderm
2. mesoderm 3. endoderm |
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Which germ layer does heart arise from? What part of that germ layer?
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Splanchnic mesoderm
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Describe the body cavities at day 18.
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They are paired and lie adjacent to the splanchnic mesoderm
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angioblastic cords
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PAIRED longitudinal cords formed by cells within the splanchnic mesoderm; earliest appearance of the heart
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endocardial heart tubes
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Angioblastic cords begin to hollow out to form these structures.
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