The embryonic disk __________.

Correct Answer: A

Rationale: In the context of pharmacology, understanding embryonic development is crucial as certain drugs can have teratogenic effects during this stage. In this question, the correct answer is A) becomes the new organism. This is because the embryonic disk is a structure formed during embryogenesis that gives rise to the developing organism. It is essential in the formation of the embryo itself. Option B) is the outer ring of cells on a blastocyst is incorrect because the embryonic disk is a distinct structure within the blastocyst that eventually develops into the embryo, not just an outer ring of cells. Option C) has a good chance of survival outside the womb is incorrect as the embryonic disk is not capable of survival on its own outside of the womb at this early stage of development. Option D) is a protective membrane that surrounds the amnion is also incorrect as the embryonic disk is a specific structure within the blastocyst and is not a protective membrane surrounding the amnion. Understanding the developmental stages of an embryo is fundamental in pharmacology to comprehend the potential impacts of drugs on prenatal development. By choosing the correct answer, students demonstrate a grasp of the basic embryonic structures critical to understanding the effects of pharmacological agents on prenatal development.

Correct Answer: D

Rationale: During the period of the embryo, the endoderm becomes the digestive system, lungs, urinary tract, and glands. The endoderm is one of the primary germ layers that give rise to various internal organs in the developing embryo. It plays a crucial role in the formation of organs such as the digestive system, respiratory system, and glandular structures.

Correct Answer: A

Rationale: In pharmacology, understanding fetal development is crucial for assessing drug safety during pregnancy. During the twelfth week of pregnancy, the correct answer is A) the sex of the fetus can be detected with ultrasound. This is because by this time, the genitalia have developed sufficiently to be visualized on an ultrasound scan, allowing for the determination of the fetus's sex. Option B) stating that the mother can feel the movements of the fetus is incorrect for the twelfth week as fetal movements, known as quickening, are typically felt between 16-25 weeks of pregnancy. Option C) claiming the fetus is viable and can survive if born early is inaccurate at 12 weeks as fetal viability, generally considered around 24 weeks, depends on various factors including lung development and weight. Option D) mentioning synchrony between fetal heart rate and motor activity peaks is not relevant at the twelfth week of pregnancy as fetal movements and cardiac activity do not yet exhibit such coordinated patterns. Educationally, knowing the timeline of fetal development is essential in pharmacology to understand how drugs may impact the developing fetus at different stages of pregnancy. Ultrasound plays a vital role in monitoring fetal growth and development, allowing healthcare providers to assess the health of the fetus and detect any potential abnormalities early on.

Correct Answer: A

Rationale: In pharmacology, understanding fetal development is crucial as it impacts drug effects on both mother and fetus. In this scenario, the correct answer is A) a 20-week-old fetus can be stimulated as well as irritated by sounds. At this stage, the fetus's auditory system is developing, allowing it to perceive sounds. This is supported by research showing fetal responses to external stimuli like music or voices. Option B) is incorrect because fetal viability outside the womb typically begins around 24 weeks, so a 20-week-old fetus would not survive if born prematurely. Option C) is incorrect as premature infants often require oxygen support to breathe due to underdeveloped lungs. Option D) is incorrect as fetal thermoregulation is not fully developed at 20 weeks, so the fetus cannot control its body temperature. Educationally, this question highlights the importance of understanding fetal development milestones for healthcare providers prescribing medications to pregnant women. It underscores the need to consider the impact of external stimuli on fetal well-being and the limitations of fetal viability and physiological functions at different gestational ages.

Correct Answer: D

Rationale: High doses of caffeine contained in coffee and tea have been linked to an increased risk of low birth weight. Consuming large amounts of caffeine during pregnancy can interfere with the baby's growth and development, leading to a lower birth weight than expected. It is important for pregnant women to limit their caffeine intake to reduce the risk of complications such as low birth weight.