Nokea
Signal 2 for T cell activation is
- A. Necessary for re-activation of memory T cells
- B. Required to develop tolerance to self-antigens
- C. Mediated by CD3
- D. Essential for the activation of naïve T cells
Correct Answer: D
Rationale: The correct answer is D because Signal 2 is essential for the activation of naïve T cells. Signal 1 provides the antigen recognition, while Signal 2, typically provided by co-stimulatory molecules, is required for full T cell activation. A is incorrect because Signal 2 is not specifically for memory T cell re-activation. B is incorrect because Signal 2 is not related to self-tolerance, which is typically maintained by regulatory T cells. C is incorrect because CD3 is a component of the T cell receptor complex, not the primary mediator of Signal 2.
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What is the primary role of phagocytosis in innate immunity?
- A. Killing cancer cells
- B. Engulfing and digesting pathogens
- C. Producing antibodies
- D. Activating complement proteins
Correct Answer: B
Rationale: The primary role of phagocytosis in innate immunity is to engulf and digest pathogens. Phagocytes such as macrophages and neutrophils recognize and engulf bacteria, viruses, and other harmful substances to prevent infections. They digest these pathogens using enzymes and destroy them. This process is crucial in the initial defense against infections. Option A is incorrect because phagocytosis primarily targets pathogens, not cancer cells. Option C is incorrect because producing antibodies is a function of adaptive immunity, not innate immunity. Option D is incorrect because activating complement proteins is a separate mechanism in the immune response.
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.
A clinical indicator of inflammation is:
- A. Decreased concentration of C3b
- B. Increased concentration of C-reactive protein
- C. Decreased concentration of MBL
- D. All of the above
Correct Answer: B
Rationale: The correct answer is B: Increased concentration of C-reactive protein. This is because C-reactive protein is a well-established clinical indicator of inflammation, produced by the liver in response to inflammation. Choice A is incorrect because a decreased concentration of C3b is not a typical indicator of inflammation. Choice C is incorrect because mannose-binding lectin (MBL) is an acute-phase reactant that increases in response to inflammation, so a decreased concentration of MBL would not be indicative of inflammation. Choice D is incorrect as it includes all options, but only B is a valid clinical indicator of inflammation.
Antihistamines are used cautiously in older men with prostatic hypertrophy for which of the following reasons?
- A. Because these clients may experience increased drowsiness
- B. Because these clients may experience difficulty voiding
- C. Because these clients face a greater risk of cardiac arrest
- D. Because these clients have a lower autoimmune response
Correct Answer: B
Rationale: Antihistamines can cause urinary retention which is particularly problematic for older men with prostatic hypertrophy.
A patient who has received a kidney transplant has been admitted to the medical unit with acute rejection and is receiving IV cyclosporine (Sandimmune) and methylprednisolone (Solu-Medrol). Which staff member is best to assign to care for this patient?
- A. An RN who floated to the medical unit from the coronary care unit for the day.
- B. An RN with 3 years of experience in the operating room who is orienting to the medical unit.
- C. An RN who has worked on the medical unit for 5 years and is working a double shift today.
- D. A new graduate RN who needs experience with IV medication administration.
Correct Answer: C
Rationale: An experienced RN who is familiar with the medical unit and its protocols is the best choice for caring for a patient with acute rejection. This patient requires close monitoring and skilled care which an experienced RN can provide. The other options involve RNs who may not be as familiar with the unit or are less experienced.