Match each term with its description. Trophoblast

Correct Answer: C

Rationale: In this question, the correct answer is C) Fertilized ovum. The trophoblast is the outer layer of cells in a fertilized ovum that plays a crucial role in implantation and the formation of the placenta during fetal development. Option A and B are marked as "None," which is incorrect as they do not provide any meaningful information related to the trophoblast. Option D is also incorrect as it does not describe the specific role or function of the trophoblast in fetal development. Educationally, understanding the structure and function of the trophoblast is essential in comprehending the early stages of fetal development. It helps students grasp how the embryo implants in the uterus and establishes the necessary connections for nutrient and waste exchange with the mother through the placenta. This knowledge is fundamental in embryology and obstetrics and provides a foundational understanding of prenatal development.

Correct Answer: D

Rationale: In fetal circulation, the ductus venosus is a crucial shunt that allows oxygenated blood to bypass the liver and flow directly into the inferior vena cava. This is essential for ensuring that the developing fetus receives oxygenated blood efficiently. Option A, connecting the pulmonary artery and the aorta, describes the ductus arteriosus, not the ductus venosus. Options B and C are incorrect as they do not pertain to the ductus venosus's function in fetal circulation. Educationally, understanding fetal circulation is important in comprehending how oxygen and nutrients are delivered to the developing fetus and how waste is removed. This knowledge is fundamental in obstetrics, pediatrics, and understanding congenital heart defects. It also highlights the unique adaptations the fetal circulatory system undergoes to support the growing fetus in utero.

Correct Answer: B

Rationale: The correct answer is B) Sixth week following the last menstrual period. This is because the fetal heartbeat typically becomes visible on ultrasound around the fifth to sixth week of pregnancy. This milestone is important as it indicates the presence of a developing embryo with a beating heart, signifying a crucial stage in fetal development. Option A) Fourth week following the last menstrual period is incorrect because it is too early for the fetal heartbeat to be visible at this stage. The heart begins to form around the third week, but it takes a few more weeks for it to develop and become detectable on ultrasound. Option C) Ninth week following the last menstrual period is also incorrect as the fetal heartbeat should be visible before this time frame. Waiting until the ninth week to see the heartbeat could indicate a potential issue with the pregnancy that needs further evaluation. Option D) Twelfth week following the last menstrual period is too late for the fetal heartbeat to be first visible. By the twelfth week, the heartbeat should not only be visible but also audible using a Doppler device, so waiting until this point to confirm the heartbeat is beyond the typical timeline for ultrasound detection. Understanding the timeline of fetal development milestones, such as when the heartbeat becomes visible, is crucial for healthcare providers and expectant parents to monitor the progress of the pregnancy and ensure the well-being of the developing fetus. Early detection of the fetal heartbeat can provide reassurance and important information about the pregnancy's viability.

Correct Answer: C

Rationale: In this scenario, option C is the correct interpretation of the fetal heart rate (FHR) accelerations observed during the nonstress test (NST) for a woman at 26 weeks gestation. The key factor here is that the FHR accelerated by 10 bpm for 10 to 15 seconds, which indicates a reassuring response. Option A is incorrect because the presence of accelerations is a positive sign, so additional monitoring may not be necessary. Option B is incorrect as it states there are too few accelerations, which is not the case in this scenario. Option D is also incorrect because fetal inactivity is not the reason behind the FHR accelerations observed. Educationally, it's crucial to understand how to interpret FHR patterns during monitoring as it provides valuable information about fetal well-being. Recognizing reassuring patterns like accelerations helps clinicians make informed decisions about the health of the fetus. This knowledge is vital for healthcare providers involved in prenatal care to ensure appropriate management and interventions when needed.

Correct Answer: A

Rationale: In this question, the correct answer is A) Both genes of a pair must be abnormal for the disorder to be expressed. This is because maple syrup urine disease (MSUD) is an autosomal recessive inherited disorder. This means that two copies of the abnormal gene, one from each parent, are needed for the disorder to manifest in the child. Option B) Only one copy of the abnormal gene is required for the disorder to be expressed is incorrect because MSUD is recessive, not dominant. If only one copy of the gene was needed, it would be a dominant disorder. Option C) The disorder occurs in males and heterozygous females is incorrect because MSUD is an autosomal recessive disorder, meaning it can affect both males and females equally if they inherit two copies of the abnormal gene. Option D) The disorder is carried on the X chromosome is incorrect because MSUD is an autosomal recessive disorder, not linked to the sex chromosomes. Educationally, understanding the principles of autosomal recessive inheritance is crucial for healthcare professionals working with families affected by genetic disorders. By grasping concepts like these, nurses can provide accurate information and support to families dealing with inherited conditions like MSUD.