Nokea
Which of the following is NOT true about the definition of acquired passive immunity
- A. Breast milk is an example
- B. It provides short term protection
- C. Can be transferred through the placenta
- D. It can be used for disease prevention
Correct Answer: E
Rationale: I'm sorry, but the correct answer is not provided in the choices given. Acquired passive immunity refers to the transfer of antibodies from one individual to another. Breast milk, placental transfer, short-term protection, and disease prevention are all characteristics of acquired passive immunity. Therefore, the correct answer is not presented in the options provided.
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The 'rapid' HIV antibody testing is performed on a patient at high risk for HIV infection. What should the nurse explain about this test?
- A. The test measures the activity of the HIV and reports viral loads as real numbers.
- B. This test is highly reliable, and in 5 minutes the patient will know if HIV infection is present.
- C. If the results are positive, another blood test and a return appointment for results will be necessary.
- D. This test detects drug-resistant viral mutations that are present in viral genes to evaluate resistance to antiretroviral drugs.
Correct Answer: C
Rationale: While rapid tests provide preliminary results quickly, confirmatory testing is required for accurate diagnosis.
Multi-photon microscopy has proved to be an invaluable tool for the evaluation of the dynamics of immune responses in vivo. The following is a list of observations derived from intra-vital microscopy. Identify the incorrect statement.
- A. T cells make stable and prolonged contacts with APC presenting the specific antigen in the paracortex
- B. In the absence of antigens B cells move at the same speed and randomly in follicles
- C. In the presence of infection specific B cells quickly direct themselves towards the source of antigen
- D. Dendritic cells move rapidly through the germinal centre during an immune response
Correct Answer: D
Rationale: The correct answer is D because dendritic cells do not typically move rapidly through the germinal center during an immune response. Dendritic cells usually interact with T cells in the paracortex to present antigens, and they are not known to migrate rapidly through the germinal center.
A: This statement is correct as T cells do make stable and prolonged contacts with APCs in the paracortex during immune responses.
B: This statement is incorrect as B cells do not move at the same speed and randomly in follicles in the absence of antigens. They respond to signals and cues in the microenvironment.
C: This statement is correct as specific B cells can quickly direct themselves towards the source of antigen during an infection.
In summary, choice D is incorrect because dendritic cells do not move rapidly through the germinal center during an immune response, while the other choices accurately describe behaviors of immune cells during immune responses.
What is the function of IgA?
- A. Allergy mediation
- B. Placental transfer
- C. Mucosal immunity
- D. Primary response
Correct Answer: C
Rationale: The correct answer is C: Mucosal immunity. IgA plays a crucial role in protecting mucosal surfaces, such as the lining of the gut and respiratory tract, from pathogens. It helps prevent infections by neutralizing and blocking the entry of harmful substances. IgA is not involved in allergy mediation (choice A), placental transfer (choice B), or primary response (choice D), as those functions are typically associated with other types of antibodies. IgA's specificity for mucosal surfaces makes it uniquely suited for providing defense at these vulnerable sites.
What is a key concept of the evolutionary arms race between hosts and pathogens?
- A. Both evolve to outcompete the other
- B. Pathogens evolve faster due to slow host mutation rates
- C. Hosts rely on chemical barriers rather than evolution
- D. Pathogens only evolve when hosts fail to adapt
Correct Answer: A
Rationale: Step 1: Evolutionary arms race involves a continuous cycle of adaptations by both hosts and pathogens to gain an advantage.
Step 2: Both parties strive to outcompete each other to survive and reproduce.
Step 3: This leads to a dynamic process where hosts evolve defense mechanisms while pathogens evolve ways to overcome them.
Step 4: Therefore, the key concept is that both hosts and pathogens evolve to outcompete each other in the evolutionary arms race.
Summary:
- Option B is incorrect as hosts can also evolve rapidly through mechanisms like recombination.
- Option C is incorrect as hosts do evolve through genetic changes, not just relying on chemical barriers.
- Option D is incorrect as pathogens continuously evolve strategies, not just when hosts fail to adapt.
What is a typical time frame for Type IV hypersensitivity reactions to develop?
- A. Within minutes
- B. 1-3 hours
- C. 24-72 hours
- D. 5-7 days
Correct Answer: C
Rationale: The correct answer is C (24-72 hours) for Type IV hypersensitivity reactions to develop. This type of reaction involves T cell-mediated immune responses, which take time to develop. Initially, sensitization occurs, followed by activation of memory T cells upon re-exposure to the antigen. This process typically takes 24-72 hours to manifest clinically. Choices A (Within minutes), B (1-3 hours), and D (5-7 days) are incorrect because Type IV reactions do not exhibit immediate responses like Type I hypersensitivity reactions (Choice A), nor do they typically take as long as 5-7 days to develop (Choice D). The time frame of 1-3 hours (Choice B) is too short for the characteristic delayed hypersensitivity reaction seen in Type IV responses.