Nokea
The dark zone of germinal centers (GC) is composed of
- A. Rapidly proliferating B cells
- B. T cells and dendritic cells
- C. Rapidly proliferating T cells
- D. Follicular dendritic cells
Correct Answer: A
Rationale: The dark zone of germinal centers is composed of rapidly proliferating B cells. This is because during the dark zone phase of the germinal center reaction, B cells undergo rapid proliferation and somatic hypermutation to generate high-affinity antibodies. T cells and dendritic cells are typically found in the light zone of the germinal centers where B cells interact with them to receive signals for selection. Rapidly proliferating T cells are not typically found in the dark zone. Follicular dendritic cells are present in the light zone where they present antigens to B cells but not in the dark zone where B cell proliferation mainly occurs.
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Before the patient receives a kidney transplant, a crossmatch test is ordered. What does a positive crossmatch indicate?
- A. Matches tissue types for a successful transplantation
- B. Determines paternity and predicts risk for certain diseases
- C. Establishes racial background and predicts risk for certain diseases
- D. Cytotoxic antibodies to the donor contraindicate transplanting this donor’s organ
Correct Answer: D
Rationale: A positive crossmatch indicates the presence of preformed cytotoxic antibodies against the donor, contraindicating transplantation.
Which of the following is not a consequence of anaphylactic shock?
- A. Constriction of airways
- B. Loss of blood pressure
- C. Hives
- D. Binding of allergen-specific IgE to mast cells
Correct Answer: D
Rationale: The correct answer is D because the binding of allergen-specific IgE to mast cells is actually a key event in anaphylactic shock, leading to the release of inflammatory mediators. Constriction of airways (A), loss of blood pressure (B), and hives (C) are all consequences of anaphylactic shock due to the systemic release of histamine and other mediators. IgE binding to mast cells triggers the release of these mediators, causing the symptoms associated with anaphylaxis. Therefore, D is the correct answer as it is not a consequence but rather an initiating event in anaphylactic shock.
You have suffered a needle stick injury after giving a patient an IM injection,but you have no information about the patient’s HIV status. What is the most appropriate method for obtaining this information about the patient?
- A. You should ask the patient to authorize HIV testing as soon as possible.
- B. The nurse manager for the unit is responsible for obtaining the information.
- C. The occupational health nurse should discuss HIV status with the patient.
- D. HIV testing should be done the next time blood is drawn for other tests.
Correct Answer: C
Rationale: The occupational health nurse is trained to handle situations involving potential exposure to bloodborne pathogens. They can appropriately discuss the need for HIV testing with the patient and ensure that the process is handled confidentially and professionally. The nurse manager and the injured nurse should not directly approach the patient about this sensitive issue.
Which of the following statements is incorrect about allergic reactions?
- A. They always require a sensitization step during which specific IgE are secreted
- B. Allergens causing hay fever are usually inhaled
- C. Food allergy can cause hives
- D. The current guidelines for preventing peanut allergy in infants is complete avoidance of peanuts and peanut-related products until at least six months of age
Correct Answer: D
Rationale: The correct answer is D because current guidelines actually recommend early introduction of peanuts to prevent peanut allergies, not complete avoidance. This is based on research showing early introduction can reduce the risk of developing peanut allergies. Choice A is correct as sensitization is a key step in allergic reactions. Choice B is correct as inhaled allergens can cause hay fever. Choice C is correct as food allergies can indeed manifest as hives.
Patients with rheumatoid arthritis typically have pain:
- A. With activity.
- B. Upon awakening.
- C. Late in the evening.
- D. All day without remission.
Correct Answer: B
Rationale: Rheumatoid arthritis often causes morning stiffness and pain upon awakening due to inflammation and lack of movement during sleep. Pain tends to improve with activity as joints warm up.