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Embryo week 4
| Question | Answer |
|---|---|
| The early heart develops in the 3rd week from _____ | endcardial tubes in the cardiogenic region |
| The cardiogenic region is located cranial to the ______ before embryo folding, but lies caudal to the mouth and ventral to the foregut after the embryo folds. | oropharangeal membrane |
| Late in the 3rd week, the endocardial tubes develop into the ______. This early heart joins with newly formed blood vessels to create a ______ | primordial heart primordial cardiovascular system |
| Blood begins to circulate and the heart beat in the ______. This is the first organ system to become functional in the embryo | 4th week (day 21-22). |
| Blood vessels develop by two processes: _______ | vasculogenesis and angiogenesis |
| ______ is the formation of new vessels by the aggregation of _____ (vessel forming cells) into clusters called ______ | Vasculogenesis Angioblasts Blood islands |
| Cavities appear in the blood islands. The ______ flatten and differentiate into endothelial cells which line the new vessel. ______ line all blood vessels in both the embryo and adult. | Angioblasts Endothelial Cells |
| ______ coalesce to form the major blood vessels Yolk sac blood islands -> vitelline vessels Umbilical blood islands -> umbilical vessels Blood islands in the embryo -> major vessels (aorta, cardinal veins) | Blood islands |
| New vessels sprout off preexisting vessels by ______ which allows the cardiovascular system to expand as the embryo grows. | Angiogenesis |
| ______, the formation of blood cells, begins in the 3rd week and continues through out life. | Hematopoiesis |
| Blood cells first develop from _____ in blood islands of the _____ | Endothelial Cells Yolk Sac |
| _______ shifts to other organs as the embryo develops: _______ to the _____, then ______ and _____ followed by the _____ (the site of adult hematopoesis). | Hematopoiesis Yolk Sac liver thymus spleen bone marrow |
| _______ are formed from different progenitor cells. They are named after the different _____ in the hemoglobin molecule: _____: Hemoglobin z2e2 _____: Hemoglobin a2g2, _____: Hemoglobin a2b2 | Fetal and adult erythrocytes Globin subunits Embryonic Fetal Adult |
| Fetal erythrocytes and hemoglobin are present for _____ after birth by which time only the adult form is found. | 6-7 months |
| Development of the embryo from a flat disk into a tube requires _____ | folding in both the cranio-caudal and lateral directions. |
| Folding results from ______. This causes the upper layer to grow faster and bend the embryo towards the lower surface of the disk. | unequal proliferation of cells on the upper surface of the disk |
| The _____ result from the elongation of the embryo in the craniocaudal direction. Elongation is mainly from growth of the nervous system. | head and tail folds |
| Folding in the ____ region causes the septum transversum (primordial diaphragm), and the cardiogenic region to move from a cranial position to lie caudal to the oropharangeal membrane (mouth) and ventral to the foregut. | head septum traversum (primordial diaphragm) cardiogenic region oropharangeal membrane (mouth) |
Created by:
sobe0015
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