Nokea
The major histocompatibility complex was given its name because the genes in this complex influence:
- A. T cell receptor gene rearrangement
- B. Acceptance or rejection of transplanted organs and cells
- C. Polarization of T helper cells
- D. The ratio of CD4+ and CD8+ T cells in an individual
Correct Answer: B
Rationale: The correct answer is B because the major histocompatibility complex (MHC) plays a crucial role in the immune system by determining whether transplanted organs or cells will be accepted or rejected. MHC molecules present antigens to T cells, which then trigger an immune response leading to acceptance or rejection. Choice A is incorrect because T cell receptor gene rearrangement is not directly influenced by the MHC. Choice C is incorrect as MHC does not directly polarize T helper cells. Choice D is incorrect because MHC does not directly regulate the ratio of CD4+ and CD8+ T cells in an individual.
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During data collection, the nurse learns the patient is allergic to shellfish. Which precautions should be implemented during the patient's hospitalization?
- A. The patient should be placed in a private room.
- B. The kitchen should use dedicated equipment for all of the patient's food preparation.
- C. Iodine-based skin preparations should be replaced with different bactericidal cleansers.
- D. The patient's allergy should be noted on the medical record and communicated clearly to all caretakers.
Correct Answer: D
Rationale: Rationale:
1. The correct answer is D because it addresses the essential action of noting the patient's allergy on the medical record and communicating it to all caretakers to prevent inadvertent exposure.
2. Choice A is not necessary unless the patient's allergy poses an infection control risk that warrants isolation.
3. Choice B is excessive and not required as long as cross-contamination is prevented during food preparation.
4. Choice C is unrelated to the patient's shellfish allergy and not a standard precaution in this scenario.
What is the process called when a specific lymphocyte binds its antigen and proliferates?
- A. Clonal deletion
- B. Clonal selection
- C. Antigen presentation
- D. Cytokine signaling
Correct Answer: B
Rationale: The correct answer is B: Clonal selection. During clonal selection, a specific lymphocyte recognizes its specific antigen, binds to it, and undergoes proliferation to generate a large population of identical cells to combat the antigen efficiently. This process ensures an effective immune response.
Incorrect choices:
A: Clonal deletion - This process involves the elimination of self-reactive lymphocytes to prevent autoimmunity, not the proliferation of antigen-specific lymphocytes.
C: Antigen presentation - This is the process by which antigens are displayed to immune cells for recognition, not the proliferation of lymphocytes.
D: Cytokine signaling - While cytokines play a role in immune responses, they are not directly involved in the proliferation of lymphocytes in response to specific antigens.
Which of the following is an example of a live attenuated bacterial vaccine?
- A. Cholera
- B. Typhoid
- C. Anthrax
- D. Plague
Correct Answer: B
Rationale: The correct answer is B: Typhoid. Live attenuated vaccines contain weakened forms of the pathogen that can replicate in the host to stimulate a strong immune response without causing disease. Typhoid vaccine is an example of a live attenuated bacterial vaccine because it contains weakened Salmonella typhi bacteria. Cholera (A), Anthrax (C), and Plague (D) vaccines are not live attenuated bacterial vaccines; they are either killed/inactivated or subunit vaccines. Live attenuated vaccines provide longer-lasting immunity compared to other vaccine types.
Why is Edward Jenner's experiment on a young boy considered a scientific landmark?
- A. Jenner inoculated the young boy using material obtained from the scabs of a milkmaid who had suffered of a very mild form of smallpox. The boy never contracted the disease.
- B. Jenner inoculated the young boy first using material obtained from the scabs of a milkmaid who had suffered of a very mild form of smallpox; subsequently he inoculated the boy with virulent smallpox.
- C. Variolation was the crude practice of injecting smallpox in a way that would supposedly protect the recipient from getting a fatal form of the disease; Jenner instead injected the young boy with cowpox. The fact that the boy did not die proved that cowpox inoculation protects against smallpox
- D. Jenner noticed the milkmaids were protected from smallpox but were often affected by a mild disease caused by cowpox. He decided to inoculate a young boy with cowpox first and subsequently with smallpox to prove that exposing people to cowpox can make them immune from getting smallpox
Correct Answer: D
Rationale: Step 1: Jenner observed milkmaids were protected from smallpox due to prior exposure to cowpox.
Step 2: Jenner decided to inoculate a young boy with cowpox first.
Step 3: Jenner then inoculated the boy with smallpox to test immunity.
Step 4: The boy did not contract smallpox, demonstrating immunity.
Step 5: Conclusion: Jenner proved cowpox exposure can make individuals immune to smallpox.
Other choices are incorrect:
A: The boy never contracted smallpox, not just because of the mild form of smallpox in the milkmaid.
B: Inoculating with virulent smallpox first would not demonstrate cowpox immunity.
C: Jenner did not just substitute cowpox for smallpox; he specifically tested immunity by exposing the boy to both viruses.
In a patient with a positive Chvostek’s sign, the nurse would anticipate the IV administration of which medication?
- A. Calcitonin
- B. Vitamin D
- C. Loop diuretics
- D. Calcium gluconate
Correct Answer: D
Rationale: Chvostek’s sign indicates hypocalcemia, so calcium gluconate is administered to restore normal calcium levels.