A nurse is caring for a primigravida who asks about the function of the placenta.The nurse responds correctly when explaining which of the following are functions of the placenta?
Cushions fetus from maternal movement.
Provides thermoregulation.
Metabolic and gas exchange.
Provides a sterile environment.
The Correct Answer is C
Choice A rationale
The placenta does not cushion the fetus from maternal movement. Instead, the amniotic fluid within the amniotic sac provides cushioning and protection to the fetus from external forces and maternal movements.
Choice B rationale
The placenta does not provide thermoregulation. Thermoregulation is primarily managed by the mother’s body. The placenta’s main functions are related to nutrient and gas exchange, hormone production, and waste removal.
Choice C rationale
The placenta is responsible for metabolic and gas exchange. It provides oxygen and nutrients to the fetus while removing waste products from the fetal blood. This exchange occurs through the placental barrier, which separates maternal and fetal blood.
Choice D rationale
The placenta does not provide a sterile environment. The amniotic sac and its fluid help maintain a sterile environment for the fetus. The placenta’s role is more focused on nutrient and gas exchange, hormone production, and waste removal.
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Correct Answer is C
Explanation
Choice A rationale
The umbilical cord does not typically contain one artery and one vein. This configuration would not provide the necessary blood flow to support fetal development. The umbilical cord must have two arteries to carry deoxygenated blood and waste products from the fetus to the placenta, and one vein to carry oxygenated blood and nutrients from the placenta to the fetus.
Choice B rationale
Two veins and one artery is also incorrect. The umbilical cord must have two arteries to ensure that deoxygenated blood and waste products are efficiently transported from the fetus to the placenta. Having only one artery would not suffice for the required blood flow.
Choice C rationale
Two arteries and one vein is the correct configuration of the umbilical cord. The two arteries carry deoxygenated blood and waste products from the fetus to the placenta, while the single vein carries oxygenated blood and nutrients from the placenta to the fetus. This arrangement is essential for maintaining proper fetal circulation during pregnancy.
Choice D rationale
Two arteries and two veins is incorrect. The umbilical cord only needs one vein to carry oxygenated blood and nutrients from the placenta to the fetus. Having two veins would be redundant and unnecessary for fetal development.
Correct Answer is B
Explanation
Choice A rationale
The mother’s size does not significantly impact the effects of teratogen exposure on fetal development. Teratogens are substances that cause congenital abnormalities in a developing fetus, and their impact is more related to the timing, duration, and type of exposure rather than the mother’s physical characteristics.
Choice B rationale
The timing and duration of exposure are critical factors in determining the effects of teratogen exposure. Teratogens can cause the most harm during specific periods of fetal development, particularly during the first trimester when organogenesis occurs. The duration of exposure also influences the severity of the effects, with prolonged exposure leading to more significant developmental issues.
Choice C rationale
The type of teratogen is also important, as different teratogens can cause different types of congenital abnormalities. For example, alcohol can lead to fetal alcohol syndrome, while certain medications can cause neural tube defects. However, the timing and duration of exposure are generally considered more critical factors.
Choice D rationale
The father’s health does not directly impact the effects of teratogen exposure on fetal development. Teratogens affect the fetus through the mother’s exposure to harmful substances during pregnancy.