The molecular mechanisms regulating cardiac development are still largely unknown. A transvaginal ultrasonography study by Wisser and Dirschedl in dated human embryos shows an increase up to 63 postmenstrual days or 22 mm greatest length. Thereafter a steady decrease of EHR was noted. Maximal EHR is reached when morphological development of the embryonic heart is completed. Images Online Links below require Internet connection.
Objectives Describe the main features of heart development to the four-chambered system.
Describe the development of the pericardium. Describe the development of primary and secondary atrial septa and the ventricular septum. Explain the changes occurring in the bulbis cordis and truncus arteriosus in its transformation from a single to a double tube. Describe the development of the aortic arches on the right and left sides from the fetus to the adult. Describe the development of arteries and veins.