3.3 Fetal Circulation Flashcards
Why shouldn’t maternal and fetal blood mix?
Because they may be different blood types.
Nutrients pass through via diffusion, such as those of water, glucose, amino acids, and inorganic salts.
What type of hemoglobin does the fetus have?
Fetal hemoglobin (HgF) . This has a greater affinity for oxygen than adult hemoglobin, so it assists with the transfer and retention of oxygen into the fetal circulatory system.
Where does gas exchange occur between the mother and the fetus?
In the placenta.
The placenta can qualify as an endocrine organ because it produces progesterone, estrogen, and hCG, which are essential for maintaining pregnancy.
Many pathogens are too large to cross the placenta, but the TORCH infections can: Toxoplasma gondii, rubella, cytomegalovirus, herpes, HIV, and Syphilis.
What doe the umbilical arteries and veins do?
The umbilical arteries carry deoxygenated blood way from the fetus.
The umbilical veins carry oxygenated blood towards the fetus.
This is the opposite of the human mother, because the blood flow with oxygen is different, and relative to the organisms heart that you are talking about.
Tell me about the lungs and the liver in the fetus.
They do not serve any significant functions. They are actually very sensitive to high blood pressure, so the body has three shunts to actively direct blood way from these organs while in utero.
Gas exchange does not occur at the lungs until birth.
Detoxification is primarily controlled by the mother’s liver.
What are the shunts that reroute blood from the lungs?
- Foramen ovale: connects the right atrium to the left atrium. In the fetus, the right side of the heart is under higher pressure, as opposed to the left side in adults. At birth, this reverses.
- The ductus arteriosus shunts leftover blood from the pulmonary artery to the aorta
What is the shunt that reroutes blood from the liver?
The ductus venosus: shunts blood returning from the placenta via the umbilical vein directly into the inferior vena cava. The liver still receives some blood supply from the systemic circulation.
In essence, the oxygenated blood bypasses the liver and goes right to the inferior vena cava. Bypasses via the ductus venosus.
In the umbilical cord, how many arteries are there? How many Veins?
2 arteries, one vein.
