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Lab 7: Vertebrate Anatomy: Difference between revisions
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→Circulatory System Adaptations for Oxygenation in the Fetus
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=='''Circulatory System Adaptations for Oxygenation in the Fetus'''== | =='''Circulatory System Adaptations for Oxygenation in the Fetus'''== | ||
While a fetus is in utero the exchange of oxygen, nutrients,and waste products occurs across the placenta. Because the digestive tract, lungs and kidneys of the fetus will not begin to function until after birth, the fetal circulation has been modified to adjust blood flow to these organs. Oxygenated blood is brought to the fetal heart through the umbilical cord | While a fetus is in utero the exchange of oxygen, nutrients,and waste products occurs across the placenta. Because the digestive tract, lungs and kidneys of the fetus will not begin to function until after birth, the fetal circulation has been modified to adjust blood flow to these organs. Oxygenated blood is brought to the fetal heart through the umbilical cord via the umbilical vein, and then the inferior vena cava. <BR><BR> | ||
Follow the umbilical vein, transected earlier in the dissection, as it seems to disappear in the liver. In Figure 7.5 there is a portion of the vein labeled <u> ductus venosus</U>, that is shunting about ½ the oxygenated blood directly to the vena cava and thus to the fetal heart. After birth the umbilical vein and umbilical arteries atrophy and the ductus venosus gradually fills with connective tissue and closes (ligamentum venosum). This is one of '''three modifications''' to the fetal circulatory system. <BR><BR> | Follow the umbilical vein, transected earlier in the dissection, as it seems to disappear in the liver. In Figure 7.5 there is a portion of the vein labeled <u> ductus venosus</U>, that is shunting about ½ the oxygenated blood directly to the vena cava and thus to the fetal heart. After birth the umbilical vein and umbilical arteries atrophy and the ductus venosus gradually fills with connective tissue and closes (ligamentum venosum). This is one of '''three modifications''' to the fetal circulatory system. <BR><BR> | ||
