The human foetal circulation and its changes following birth

Zusammenfassung

In 1628 William Harvey (17) introduced the first account of the foetal blood flow. In this account he integrated the best available anatomical data about the cardiovascular system with his own dynamic concept of the circulation. He makes the following statement :

“It is, however, to be noted that these matters are otherwise arranged in the embryo, and there is not the same degree of difference between the ventricles, which are arranged almost equally, like twin kernels in a double nut. The cone of the right ventricle reaches to the tip of the left ventricle, so that the heart in the foetus is like a cone with two tips. This is so (as I have already stated) because in the foetus the blood is not passing through the lungs from the right ventricle into the left one. On the contrary, these two chambers are both busy with a single task (namely, the transference of blood from the vena cava into the aorta, though one does it through the foramen ovale, and the other through the artery-like passage, as I have already stated), and have identical parts to play in the propulsion of the blood to the whole of the body. Hence the identity in their dispositions. When, however, it is time for the lungs to function and for the abovementioned unions to be occluded, the ventricles begin to differ in strength and in the other respects noted, because the right ventricle now propels the blood through the lungs only, but the left ventricle propels it through the whole of the body.”