Nokea
All of the following are true with respect to IgE molecules, EXCEPT which one?
- A. They are the principal immunoglobulin class involved in allergic reactions.
- B. They are involved in mediating anti-parasitic immune responses.
- C. They will cross the placenta and fix complement.
- D. They can effect the release of histamine and other chemical mediators.
Correct Answer: C
Rationale: The correct answer is C. IgE molecules do not cross the placenta and fix complement, unlike IgG. IgE is the principal immunoglobulin in allergic reactions (A), mediates anti-parasitic immune responses (B), and triggers the release of histamine and other mediators (D). IgE plays a specific role in allergic responses and defense against parasites. IgG is the main immunoglobulin that crosses the placenta and fixes complement. Therefore, IgE does not share this function.
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Which historical event provides evidence for immune adaptation?
- A. Spanish flu pandemic
- B. The Black Death caused by Yersinia pestis
- C. HIV/AIDS epidemic
- D. The eradication of smallpox
Correct Answer: B
Rationale: The Black Death caused by Yersinia pestis is the correct answer because it led to immune adaptation in survivors. Yersinia pestis triggered the body to develop immunity. The Spanish flu pandemic, HIV/AIDS epidemic, and eradication of smallpox did not directly result in immune adaptation like the Black Death. The Spanish flu and HIV/AIDS were caused by viruses that did not lead to long-term immunity, and smallpox eradication was achieved through vaccinations, not natural immune adaptation.
The nurse is caring for a patient who has had a total hip replacement and is using an abductor wedge. For which finding should the nurse assess?
- A. Muscle spasms
- B. Alteration in peripheral circulation
- C. Compression fracture
- D. Appropriateness of the size of the wedge
Correct Answer: B
Rationale: The correct answer is B: Alteration in peripheral circulation. The abductor wedge can affect blood flow to the legs, leading to potential complications like deep vein thrombosis. The nurse should assess for signs of impaired circulation such as color changes, temperature differences, and peripheral pulses. Muscle spasms (A) may occur due to the surgery but are not directly related to the wedge. Compression fracture (C) is not typically a concern with an abductor wedge. Assessing the appropriateness of the wedge size (D) is important but not as critical as monitoring for alterations in peripheral circulation.
Which part of an antibody determines its antigen specificity?
- A. Fc fragment
- B. Fab region
- C. Heavy chain constant region
- D. Light chain constant region
Correct Answer: B
Rationale: The correct answer is B: Fab region. The Fab region of an antibody contains the antigen-binding site, where specific interactions with antigens occur. This region is formed by the variable regions of both the heavy and light chains. The Fc fragment (choice A) is responsible for effector functions, not antigen specificity. The heavy chain constant region (choice C) and light chain constant region (choice D) are not involved in antigen binding, but rather provide structural support and determine the antibody class. Therefore, the Fab region is crucial for antigen specificity due to its variable regions that directly interact with antigens.
Which characteristics are seen with acute transplant rejection (select all that apply)?
- A. Treatment is supportive
- B. Only occurs with transplanted kidneys
- C. Organ must be removed when it occurs
- D. The recipient’s T cytotoxic lymphocytes attack the foreign organ
Correct Answer: D
Rationale: Acute transplant rejection involves the recipient's T cytotoxic lymphocytes attacking the transplanted organ, requiring immunosuppressive therapy.
The nurse is preparing an injection for an individual who requires passive immunity. In which situation would passive immunity be indicated?
- A. For permanent immunity against a disease
- B. To overcome an allergic reaction that is relatively mild
- C. To have ready-made antibodies after an exposure to pathogens
- D. As a booster dose to stimulate the production of specific antibodies
Correct Answer: C
Rationale: Passive immunity is indicated when an individual needs immediate protection with ready-made antibodies after exposure to pathogens. This is the correct answer (C) as it provides immediate defense without waiting for the body to produce its antibodies. Choice A is incorrect because passive immunity is temporary, not permanent. Choice B is incorrect as it addresses treating allergic reactions, not providing immunity. Choice D is incorrect as a booster dose stimulates the body to produce its antibodies, not providing ready-made antibodies.