Developing fetuses obtain nutrients from their parent’s bloodstream via diffusion (Figure 1). Fetal blood enters arteries in the placenta, which branch into villus capillaries. Parental blood passes through the spiral arteries in the placenta and enters the intervillous space. Membrane transport happens across the villus. In the first trimester of pregnancy, the total surface area of villus capillaries is ~1.5m2, and the thickness of the villus is ~170μm. During the third trimester, the total surface area of the villus capillaries increases to ~12m2, and the thickness of the villus shrinks to ~40μm. Using Fick’s Law of Diffusion, estimate how many times greater uteroplacental blood flow (mL/min) is in the third trimester compared to the first trimester. Briefly explain how you reached your answer.
Developing fetuses obtain nutrients from their parent’s bloodstream via diffusion (Figure 1). Fetal blood enters arteries in the placenta, which branch into villus capillaries. Parental blood passes through the spiral arteries in the placenta and enters the intervillous space. Membrane transport happens across the villus.
In the first trimester of pregnancy, the total surface area of villus capillaries is ~1.5m2, and the thickness of the villus is ~170μm. During the third trimester, the total surface area of the villus capillaries increases to ~12m2, and the thickness of the villus shrinks to ~40μm. Using Fick’s Law of Diffusion, estimate how many times greater uteroplacental blood flow (mL/min) is in the third trimester compared to the first trimester. Briefly explain how you reached your answer.
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