Question at position 3 A newly pregnant woman is warned by a doctor about teratogens. She does not know what these are and wants to look them up in a book, but is unsure where to look. You tell her that the teratogens named in your text includedopaminetestosteronesugaralcoholserotonin单项选择题
A
dopamine
B
testosterone
C
sugar
D
alcohol
E
serotonin

Question

Question at position 3 A newly pregnant woman is warned by a doctor about teratogens. She does not know what these are and wants to look them up in a book, but is unsure where to look. You tell her that the teratogens named in your text includedopaminetestosteronesugaralcoholserotonin单项选择题

A

dopamine

B

testosterone

C

sugar

D

alcohol

E

serotonin

BlackTom AI · Accepted Answer

Teratogens are agents that cause structural or functional birth defects when a developing embryo or fetus is exposed during critical periods (especially weeks 3–8 for organogenesis). Key concepts include timing (earlier exposures more likely to produce major malformations), dose-response (higher exposure usually worse), and specific mechanisms (e.g., disrupting cell proliferation, migration, or signaling).

1) Relevant knowledge points and concepts
- Definition: teratogen = an environmental agent (drug, chemical, infection, radiation) that can cause congenital anomalies or functional deficits.
- Classic, well-documented teratogens: alcohol (causes fetal alcohol spectrum disorders), certain drugs (thalidomide, retinoic acid), some infections (rubella, cytomegalovirus), and high levels of ionizing radiation.
- Mechanism for alcohol: readily crosses the placenta, fetal metabolism is limited, and alcohol disrupts cell signaling, causes oxidative stress and apoptosis—especially damaging to the developing brain and face.

2) Step-by-step reasoning to select the correct option
- Inspect each answer choice for whether it is a known teratogen commonly named in textbooks.
- Dopamine and serotonin are endogenous neurotransmitters; while drugs that modify their signaling have reproductive considerations, the neurotransmitters themselves are not listed as classic teratogens.
- Testosterone (endogenous androgen) in physiologic maternal levels is not a common textbook teratogen; although high/exogenous androgen exposure can virilize a female fetus, it is not the canonical example listed here.
- Sugar is a nutrient; maternal hyperglycemia (diabetes) increases congenital risk, but "sugar" itself is not classed as a teratogen.
- Alcohol is a prototypical teratogen universally cited in texts (fetal alcohol syndrome: growth deficiency, facial features, CNS impairment).

3) Calculations: none required.

4) Why the correct answer is correct
- Alcohol is explicitly and repeatedly described in medical and developmental biology texts as a teratogen because of clear epidemiologic and mechanistic evidence linking prenatal exposure to characteristic structural and neurodevelopmental defects.

5) Why other options are incorrect (brief)
- Dopamine/serotonin: endogenous neurotransmitters, not classic teratogens.
- Testosterone: exogenous androgens can affect development but aren’t the standard teratogen listed here.
- Sugar: dietary nutrient; maternal diabetes increases risk but sugar itself is not classified as a teratogen.

Conclusion: The correct answer is alcohol, which matches the provided answer.

Question at position 3 A newly pregnant woman is warned by a doctor about teratogens. She does not know what these are and wants to look them up in a book, but is unsure where to look. You tell her that the teratogens named in your text includedopaminetestosteronesugaralcoholserotonin单项选择题

类似问题

During prenancy, alcohol would be considered a:

When are teratogens most harmful during pregnancy? Choose the best advice you should give based on what you have learned in this course.

Question at position 7 Reproductive toxins only affect pregnant women. TrueFalse

The embryonic period is the most sensitive time for teratogen exposure.

True or false? If a teratogen is introduced after a particular organ has formed, it may not have much of an effect on the structure of that particular organ.

Children whose mothers drank alcohol during pregnancy often have a specific set of facial features, may have heart defects, and brain damage. Children whose mothers took thalidomide for morning sickness may have malformed limbs. These examples illustrate

Which of the following options is an accurate description of the effects of teratogens?

What is a teratogen?

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