Fetal Blood Supply
In the growing fetus, a major source of blood to the liver is the umbilical vein which supplies nutrients to the growing fetus. The umbilical vein enters the abdomen at the umbilicus, and passes upward along the free margin of the falciform ligament of the liver to the inferior surface of the liver. There it joins with the left branch of the portal vein. The ductus venosus carries blood from the left portal vein to the left hepatic vein and then to the inferior vena cava, allowing placental blood to bypass the liver.
In the fetus, the liver develops throughout normal gestation, and does not perform the normal filtration of the infant liver. The liver does not perform digestive processes because the fetus does not consume meals directly, but receives nourishment from the mother via the placenta. The fetal liver releases some blood stem cells that migrate to the fetal thymus, so initially the lymphocytes, called T-cells, are created from fetal liver stem cells. Once the fetus is delivered, the formation of blood stem cells in infants shifts to the red bone marrow.
After birth, the umbilical vein and ductus venosus are completely obliterated in two to five days; the former becomes the ligamentum teres and the latter becomes the ligamentum venosum. In the disease state of cirrhosis and portal hypertension, the umbilical vein can open up again.
Read more about this topic: Hepar, Development
Famous quotes containing the words blood and/or supply:
“Now it is time to call attention
to our bed, a forest of skin
where seeds burst like bullets.
We are in our room. We are in
a shoe box. We are in a blood box.”
—Anne Sexton (1928–1974)
“Dear to us are those who love us ... but dearer are those who reject us as unworthy, for they add another life; they build a heaven before us whereof we had not dreamed, and thereby supply to us new powers out of the recesses of the spirit, and urge us to new and unattempted performances.”
—Ralph Waldo Emerson (1803–1882)