bio question

[elz787]

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does anyone know why the ductus venosus shunts blood away from the fetal liver?

 

[dat_student]

does anyone know why the ductus venosus shunts blood away from the fetal liver?

that's one of the gray areas but one can argue a fetal liver doesn't need to be developed extensively (e.g. liver doesn't need to be extensively involved in the production of urea) Ductus arteriosus is more explainable.

bb in 8-9 hrs

 

[ISU_Steve]

Because of the fact that the developing fetus has the mother's liver to filter waste products and also because the liver is not actively producing (at least not in great quantities) digestive and other enzymes in utero so therefore it does not have the metabolic demands it has after birth.


Remember, the umbilical vein carries oxygenated blood into the baby, into the ductus venosus, and one third goes through the lower trunk and extremites. The remaining roughly 2/3 of the blood is shunted past the liver by the ductus venosus, into the inferior vena cava, mixing with the deoxygenated blood coming back to the heart from the lower body and enters the right atrium.

 

[Divineimpetus]

Is it the fetal liver that produces and destroys all blood cells?

I'm kind of confused with the fetal liver/spleen. Can anyone help?

 

[verticlebite]

does anyone know why the ductus venosus shunts blood away from the fetal liver?

HONESTLY, does anyone think this level of detail will appear on the DAT?

 

[ISU_Steve]

The spleen plays a role in the removal of damaged and old RBC's and the liver plays a role in the production of erythropoietin which stimulates production of RBC's. At least this is how it works in a person after birth, I'm not sure how it works prior to birth though.

 

[captaintripps]

The spleen plays a role in the removal of damaged and old RBC's and the liver plays a role in the production of erythropoietin which stimulates production of RBC's. At least this is how it works in a person after birth, I'm not sure how it works prior to birth though.

Erythropoietin is produced by the kidney.

 

[ISU_Steve]

It's also produced by the liver, although you are right, it is made in the greatest quantities by the renal cortex as a result of low partial pressures of oxygen in the peritubular capillaries. But if my memory serves me correctly, the liver produces more during gestation than does the kidney.

Here you go: "Erythropoietin is the primary hormone regulator of red blood cell (RBC) production. In the fetus, erythropoietin comes from the monocyte/macrophage system of the liver. Postnatally, erythropoietin is produced in the peritubular cells of the kidneys."

SOURCE: http://www.aafp.org/afp/20011015/1379.html
Irwin JJ and Kirchner JT: Anemia in Children. American Family Physician. 15 Oct 2001.