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Atlas of Human Embryos Chapter   Figure

atrioventricular canal, cut edge of amnion, edge of septum tranversum, edge of sinus venosus, edge of umbilical vesicle cavity, foregut, left dorsal aorta, notochord, pericardial cavity, pericardial sac, primitive left atrium, primitive right atrium, rhombencephalon (postotic), somite 1 (O-1)

A section through somite 1, the primitive atria of the heart and the cranial edge of the yolk sac cavity.

Observe:
1. The separation of the pericardial cavity from the yolk sac cavity by the septum transversum.
2. The narrow atrioventricular canal that connects the two atria to the primitive ventricle in Section 7.
3. The close relation of foregut endoderm to the primitive atria.
4. The close association of the neural tube, somite 1 and the dorsal aorta.
5. The attachment of the amnion to the lateral aspect of the pericardium.


Keywords: atrioventricular canal, cut edge of amnion, edge of septum tranversum, edge of sinus venosus, edge of umbilical vesicle cavity, foregut, left dorsal aorta, notochord, pericardial cavity, pericardial sac, primitive left atrium, primitive right atrium, rhombencephalon (postotic), somite 1 (O-1)

Source: Atlas of Human Embryos.