Through the blood vessels in the umbilical cord, the fetus gets all needed nutrition and oxygen. The fetus gets life support from the mother through the placenta.
Waste products and carbon dioxide from the fetus are sent back through the umbilical cord and placenta to the mother's circulation to be removed. The fetal circulatory system uses 3 shunts. These are small passages that direct blood that needs to be oxygenated. The purpose of these shunts is to bypass the lungs and liver. That's because these organs will not work fully until after birth. The shunt that bypasses the lungs is called the foramen ovale. This shunt moves blood from the right atrium of the heart to the left atrium.
The ductus arteriosus moves blood from the pulmonary artery to the aorta. Oxygen and nutrients from the mother's blood are sent across the placenta to the fetus. The enriched blood flows through the umbilical cord to the liver and splits into 3 branches. Blood from the umbilical vein gets mixed with the rest of the systemic circulation and returns to the right atrium.
The fetus has two key tricks to adapt to this fact:. First, some of the blood that leaves the right ventricle bypasses the lungs. In an adult, this blood needs to go to the lungs to get oxygenated, but the fetus has a ductus arteriosus that short-circuits this blood flow, allowing some blood to go directly into the aorta and then into the systemic circulation.
Second, in the fetal heart, there is an opening between the right atrium and the left atrium. This opening is called the foramen ovale. The foramen ovale is helpful in the fetus because it lets the oxygenated blood from the placenta get circulated faster. The circulation pattern is somewhat similar to that of a frog Campbell, p. The foramen ovale normally closes up at birth, keeping blood flow of the two sides of the heart completely separate.
In some people, the foramen ovale does not close up. This condition, called patent foramen ovale, can result in serious health problems. Image courtesy of OpenWetWare. You should be prepared to identify any of the structures labeled on the diagrams on this page or listed in bold type in the text of this page.
You might see either of the two specimens shown on this page, or a dissected specimen like the one you examined in lab. Click through all the links for an excellent step-by-step dissection guide. Assessment of flow distribution in the mouse fetal circulation at late gestation by high-frequency Doppler ultrasound. Zhou et al. This research article presents some amazingly detailed ultrasound images of fetal circulation in a mouse.
Enjoy it for the pictures. Fetal Circulation Right Before Birth. This Khan Academy video gives a clear explanation of fetal circulation. Osmoregulation Problems Answer these in lab! Plants I The evolution of land plants. Animal Phyla. Chordates Overview of the phylum Chordata. Fetal Pig Anatomy In this lab you'll dissect a fetal pig to get a look at the anatomy of a mammal. Waste products from the fetal blood are transferred back across the placenta to the mother's blood.
Blood enters the right atrium, the chamber on the upper right side of the heart. When the blood enters the right atrium, most of it flows through the foramen ovale into the left atrium.
Blood then passes into the left ventricle lower chamber of the heart and then to the aorta, the large artery coming from the heart. From the aorta, blood is sent to the heart muscle itself in addition to the brain.
After circulating there, the blood returns to the right atrium of the heart through the superior vena cava. About two thirds of the blood will pass through the foramen ovale as described above, but the remaining one third will pass into the right ventricle, toward the lungs. In the fetus, the placenta does the work of breathing instead of the lungs. Why is circulation to the lungs bypassed in fetal pigs? What are the two fetal circulation bypasses found in the fetal pig?
What structure is used to connect the aorta and the pulmonary artery in fetal circulation? In fetal circulation the ductus arteriosus? In fetal circulation the small vessel connecting the pulmonary artery with the descending thoracic aorta is called the? Why is it important for the fetal heart to have both the ductus arteriosus and the foramen ovale but not good for the adult heart to have these feature?
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Difference between postnatal circulation and fetal circulation? In the fetal circulation the opening between the artium and the left artium is the? What phylum does fetal pigs belong to? What three types of vessels are seen in a fetal pig lung? Which veins carry oxygenated blood in fetal circulation? How does one check fetal circulation?
What major organ system is bypassed in fetal circulations other than for purpose of nutrition? How long can a fetal pig live? Study Guides. Trending Questions. What is the fourth element of the periodic table of elements?
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