Henry Gray (18251861). Anatomy of the Human Body. 1918.
to the lower extremities and the viscera of the abdomen and pelvis, but the greater amount is conveyed by the umbilical arteries to the placenta.
FIG. 502 Plan of the fetal circulation. In this plan the figured arrows represent the kind of blood, as well as the direction which it takes in the vessles. Thusarterial blood is figured >>; venous blood, >>; mixed (arterial and venous) blood, >>. (See enlarged image)
From the preceding account of the circulation of the blood in the fetus the following facts will be evident: (1) The placenta serves the purposes of nutrition and excretion, receiving the impure blood from the fetus, and returning it purified and charged with additional nutritive material. (2) Nearly the whole of the blood of the umbilical vein traverses the liver before entering the inferior vena cava; hence the large size of the liver, especially at an early period of fetal life. (3) The right atrium is the point of meeting of a double current, the blood in the inferior