Nokea
With respect to vaccination against a particular infectious disease 'herd immunity' refers to:
- A. The total number of people who are immunized in a given population
- B. The protection offered to non-immunized people when high rates of immunization prevent the pathogen from spreading
- C. The percentage of people who generate a protective response to the vaccine
- D. The tendency of people to choose to be vaccinated if close contacts (friends and family) have been vaccinated
Correct Answer: B
Rationale: The correct answer is B. Herd immunity refers to the protection offered to non-immunized individuals when a high percentage of the population is immunized, preventing the pathogen from spreading easily. This is because when a large portion of the population is immune to a disease, it creates a barrier that reduces the overall transmission of the pathogen, thus protecting those who are not vaccinated or cannot be vaccinated.
Choice A is incorrect because herd immunity is not solely about the total number of immunized individuals, but rather about the impact on the entire population. Choice C is incorrect as it refers to the efficacy of the vaccine in generating a protective response, not the concept of herd immunity. Choice D is incorrect as it relates to social influence rather than the collective protection provided by high rates of immunization.
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Which of the following statement is incorrect
- A. Antigens in tissues can reach regional LN via afferent lymphatic vessels
- B. Migrating dendritic cells that have collected antigens in tissues enter the draining LN via HEV
- C. During an infection fever and other inflammatory signals induce increased blood flow to draining LN and increased chances for lymphocytes to migrate from blood into LN
- D. The thoracic duct returns most of the circulating lymphocytes back to blood
Correct Answer: B
Rationale: The correct answer is B because migrating dendritic cells do not enter the draining lymph node (LN) via high endothelial venules (HEV); instead, they enter through afferent lymphatic vessels. HEVs are specialized post-capillary venules in LN where lymphocytes enter from the bloodstream. Dendritic cells, carrying antigens from tissues, travel via afferent lymphatic vessels to reach the LN where they present antigens to lymphocytes. Option A is correct as antigens in tissues reach LN via afferent lymphatic vessels. Option C is correct as infection-induced signals can increase blood flow to LN, facilitating lymphocyte migration. Option D is incorrect because the thoracic duct returns lymph back to the bloodstream, not specifically lymphocytes.
The clonal selection theory explains:
- A. That one given lymphocyte expresses multiple antigen receptors with different specificity
- B. That antigens influence the generation of antigen receptors during lymphocyte development
- C. How the immune response to an antigen increases the number of lymphocytes specific for that antigen
- D. The increase in blood neutrophils observed during bacterial infections
Correct Answer: C
Rationale: Rationale:
1. Clonal selection theory states that specific lymphocytes are activated by antigens.
2. Upon activation, these lymphocytes proliferate to form a clone of cells specific to the antigen.
3. This increases the number of lymphocytes specific for the antigen.
4. Choice C correctly aligns with the essence of clonal selection theory.
Summary:
A: Incorrect - Clonal selection theory does not involve a single lymphocyte expressing multiple antigen receptors.
B: Incorrect - Antigens do not influence the generation of antigen receptors, but rather activate specific lymphocytes.
D: Incorrect - Clonal selection theory focuses on lymphocyte response to antigens, not neutrophil increase during infections.
Which of the following is NOT a secondary lymphoid organ?
- A. Bone marrow
- B. Spleen
- C. Lymph nodes
- D. Mucosal immune system
Correct Answer: A
Rationale: The correct answer is A: Bone marrow. Secondary lymphoid organs are where immune responses are initiated. Bone marrow is a primary lymphoid organ where immune cells mature, not where immune responses are initiated like in secondary lymphoid organs. The spleen, lymph nodes, and mucosal immune system are all secondary lymphoid organs where immune responses occur.
Priority Decision: The patient with advanced cancer is having difficulty controlling her pain. She says she is afraid she will become addicted to the opioids. What is the first thing the nurse should do for this patient?
- A. Administer a nonsteroidal antiinflammatory drug
- B. Assess the patient’s vital signs and behavior to determine the medication to use
- C. Have the patient keep a pain diary to better assess the patient’s potential addiction
- D. Obtain a detailed pain history including quality,location intensity duration and type of pain
Correct Answer: D
Rationale: A detailed pain history helps tailor pain management strategies and alleviates concerns about addiction.
When was the first vaccine for smallpox developed?
- A. 1726
- B. 1796
- C. 1882
- D. 1895
Correct Answer: B
Rationale: The correct answer is B: 1796. This is because the first vaccine for smallpox was developed by Edward Jenner in 1796. He used cowpox virus to create immunity against smallpox. Choices A, C, and D are incorrect because they do not align with historical records of the development of the smallpox vaccine. Choice A (1726) is too early, choices C (1882) and D (1895) are much later dates and do not correspond to the actual timeline of the smallpox vaccine's discovery.