Which of the following cell types is primarily responsible for presenting antigens to T cells during the immune response?

Correct Answer: C

Rationale: The correct answer is C: Macrophages. Macrophages are antigen-presenting cells that engulf pathogens and present their antigens to T cells, initiating an immune response. They express major histocompatibility complex (MHC) molecules necessary for T cell recognition. B cells also present antigens but primarily to B cells for antibody production. NK cells are involved in killing infected cells, not antigen presentation. Eosinophils are mainly involved in allergic responses and defense against parasites, not antigen presentation.

Correct Answer: B

Rationale: The correct answer is B: Acute myocardial infarction (MI) is the most common cause of cardiogenic shock. During an MI, there is significant damage to the heart muscle, leading to a decrease in cardiac output and subsequent shock. This results in inadequate tissue perfusion and oxygen delivery. Choices A, C, and D are incorrect because decreased hemoglobin level (A) may lead to anemia but is not the most common cause of cardiogenic shock. Hypotension (C) is a symptom of shock, not the cause. Coronary artery disease (D) is a risk factor for MI but not the direct cause of cardiogenic shock.

Correct Answer: C

Rationale: The correct answer is C: Acquired von Willebrand syndrome. This condition is characterized by a defect in von Willebrand factor function, leading to prolonged bleeding time and mucocutaneous bleeding. Normal platelet count rules out Glanzmann thrombasthenia and Bernard-Soulier syndrome which are platelet disorders. Normal PT and aPTT rule out Hemophilia A, a coagulation factor deficiency. Acquired von Willebrand syndrome is the most likely cause based on the clinical presentation and laboratory findings.

Correct Answer: B

Rationale: The primary reason for surgical repair of myelomeningocele is to correct the neurologic defect. This is because myelomeningocele is a type of neural tube defect where the spinal cord and its protective covering do not close properly. Surgical repair aims to close the opening in the spinal cord to prevent further damage, improve neurological function, and reduce the risk of complications such as paralysis and infection. The other choices are incorrect as they are not the primary goal of the surgery. Preventing infection (Choice A) is important but not the primary reason. Seizure disorders (Choice C) and hydrocephalus (Choice D) may be associated complications but are not the main purpose of the surgical repair.

Correct Answer: A

Rationale: The correct answer is A: Identify and count cases. In the initial stages of an outbreak investigation, it is crucial to identify and count cases to understand the scope and magnitude of the outbreak. By counting cases, Nurse Rona and her team can track the spread of the disease, identify common characteristics among those affected, and determine the extent of the outbreak. This step helps in guiding further investigation and control measures. Summary of other choices: B: Define and identify cases - While defining cases is important, it is not the initial step in outbreak investigation. C: Verify diagnosis - Verifying diagnosis is important but comes after identifying and counting cases. D: Prepare for field work - Field work is important in outbreak investigations, but it typically comes after the initial step of identifying and counting cases.

Correct Answer: A

Rationale: Encouraging early ambulation and progressive activity as tolerated is the most appropriate nursing intervention to promote optimal recovery for a postpartum client who delivered via cesarean section. Early ambulation helps prevent complications such as blood clots, pneumonia, and constipation. It also promotes circulation and facilitates healing by reducing the risk of postoperative complications. Progressive activity helps the client regain strength, mobility, and independence, which are essential for a speedy recovery. Restoring normal movement will also help decrease discomfort and improve the client's overall well-being. In contrast, restricting movement may lead to complications and delayed recovery. Administering oral analgesics as needed is important for pain management, but promoting early ambulation is essential for optimal recovery. Heat packs should not be applied to the incision site as they can increase the risk of infection and interfere with proper wound healing.

Correct Answer: C

Rationale: The correct answer is C: Systematic sampling. Nurse Sandy is adopting systematic sampling by selecting every third patient with MI after a random start. This method ensures equal chance of selection for each patient and maintains randomness. In contrast, simple random sampling (A) entails each patient having an equal chance of being selected independently. Stratified sampling (B) divides patients into groups based on certain characteristics, which is not the case here. Cluster sampling (D) involves grouping patients and selecting entire groups, which is different from the individual selection in this scenario.

Correct Answer: A

Rationale: The correct answer is A: Justice. Nurse Erika is ensuring fairness by including all newly hired nurses in her project without discrimination. Justice in healthcare promotes equity and equal opportunities. Nonmaleficence (B) refers to the duty to do no harm, not relevant here. Autonomy (C) relates to respecting individuals' right to make decisions for themselves, not evident in the scenario. Respect (D) is important but not the primary ethical principle demonstrated here.

Correct Answer: C

Rationale: In a postpartum client complaining of persistent, heavy vaginal bleeding, the most appropriate nursing action is to assess vital signs and uterine tone. This is important to determine if the bleeding is within normal limits or if there is a potential postpartum hemorrhage (PPH) occurring. Monitoring vital signs can help identify signs of shock, while assessing uterine tone can help determine if the uterus is contracting effectively to control bleeding. Prompt assessment and early detection of PPH are crucial for effective management and prevention of complications. Encouraging increased fluid intake, applying a cold compress, and administering pain medication may be appropriate interventions in some situations, but assessing vital signs and uterine tone take priority in this scenario.