Correct Answer: B

Rationale: The correct answer is B. Myelination occurs in a cephalocaudal (head-to-toe) pattern, improving nerve function progressively. Choice A is incorrect as myelination continues into adolescence and beyond, not just during childhood. Choice C is incorrect because myelination actually increases the speed of nerve impulses rather than decreasing it. Choice D is incorrect as myelination enhances the specificity of nerve impulses, making them more efficient and precise rather than less specific.

Correct Answer: B

Rationale: When managing a child with partial thickness burns over the upper body areas, the priority action during the primary survey is to assess for a patent airway. This step is crucial as burns in this region can lead to airway compromise, potentially causing rapid deterioration in the child's condition. Checking for a patent airway ensures that the child can breathe adequately, which is essential for oxygenation and ventilation. Inspecting the child's skin color (Choice A) is an important assessment but should follow ensuring a patent airway. Observing for symmetric breathing (Choice C) is relevant, but the immediate focus should be on securing the airway. Palpating the child's pulse (Choice D) is also a vital assessment, but in this scenario, the priority is to assess and maintain a clear airway to support respiratory function and oxygen delivery.

Correct Answer: D

Rationale: The correct answer is D: surgical removal of the affected section of bowel. Hirschsprung disease is characterized by a segment of the colon lacking nerve cells, leading to obstruction. The definitive treatment involves surgically removing the affected segment, followed by a pull-through procedure to restore normal bowel continuity. Daily enemas (choice A) are not the primary treatment for Hirschsprung disease. While dietary adjustments may be advised, a low-fiber diet (choice B) alone is not curative for this condition. A permanent colostomy (choice C) is considered a last resort if surgical interventions fail or in severe cases, but it is not the initial therapeutic approach for managing Hirschsprung disease.

Correct Answer: B

Rationale: Rectal biopsy is the definitive diagnostic procedure for Hirschsprung disease in infants. This procedure reveals the absence of ganglion cells in the affected bowel segment, which is a hallmark of Hirschsprung disease. Colonoscopy (Choice A) is not typically used for diagnosing Hirschsprung disease due to the risk of not accurately reaching the affected segment. Multiple saline enemas (Choice C) are not used to confirm the diagnosis of Hirschsprung disease. Fiberoptic nasoenteric tube (Choice D) is not a standard diagnostic procedure for Hirschsprung disease and does not provide the necessary information to confirm the absence of ganglion cells in the affected bowel segment.

Correct Answer: A

Rationale: Preventing shivering is crucial in this scenario as it can increase body temperature and counteract the effects of antipyretic measures aimed at reducing the fever. Shivering generates heat through muscle activity, which can elevate the body temperature. Restricting oral fluids (choice B) is inappropriate as maintaining hydration is vital, especially in cases of fever and vomiting. Measuring output hourly (choice C) and taking vital signs hourly (choice D) are important nursing actions but not the most critical in this case where preventing shivering takes precedence.