Early Development, Devel. Physiol., Dr. D. Penney




Table 2.04 - Summary of Developmental Events in the Cardiovascular System. See Time of Occurrence of Normal Events, A. & B.


Ovulation age [in days]Approximate sizeEvent
18presomiteangiogenic tissue appears, vitelline vessels appear
19 - 201 - 2 somitesappearance of endothelial heart tube, umbilical veins appear

214 - somitesfusion of endothelial heart tube
21-226 somitesdifferentiation of atria, ventricle and bulbus cordis
2514 - 16 somitesfusion of primitive atria, formation of bulboventricular loop
26 - 2720 somites to 10 mmPharyngeal arch arteries appear
2826 somitesarterior cardinal veins appear
293.5 mmposterior cardinal veins appear
325 mmseptum primum appears
336 mminterventricular septum appears
33 - 346 - 7 mmright umbilical vein disappears
358 mmforamen secundum present
36 - 379 - 10 mmatrial cushions fuse
4315 mm bulbar ridges fuse
4617 mminterventricular foramen closed
4718 mmseptum secundum appears



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