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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Select the correct statement during an allergic reaction.
- A. An allergen binds with IgE antibodies.
- B. The mast cells are deactivated.
- C. The body is immunodeficient.
- D. Helper T cells release histamine.
Correct Answer: A
Rationale: Step-by-step rationale:
1. During an allergic reaction, allergens trigger the release of IgE antibodies.
2. The allergen binds with IgE antibodies, leading to the activation of mast cells.
3. Activated mast cells release histamine and other inflammatory mediators.
4. This cascade of events causes allergic symptoms.
Therefore, option A is correct as it accurately describes the initial binding of allergen with IgE antibodies. Option B is incorrect as mast cells are activated, not deactivated. Option C is incorrect as the body is hypersensitive, not immunodeficient. Option D is incorrect as it is mast cells, not Helper T cells, that release histamine.
What describes a primary use of biologic therapy in cancer treatment?
- A. Protect normal,rapidly reproducing cells of the gastrointestinal system from damage during chemotherapy
- B. Prevent the fatigue associated with chemotherapy and high-dose radiation as seen with bone marrow depression
- C. Enhance or supplement the effects of the host’s immune responses to tumor cells that produce flu-like symptoms
- D. Depress the immune system and circulating lymphocytes as well as increase a sense of well-being by replacing central nervous system deficits
Correct Answer: C
Rationale: Biologic therapy enhances the immune response against tumor cells, often causing flu-like symptoms.
Where do B cells mature?
- A. Bone marrow
- B. Thymus
- C. Spleen
- D. Lymph nodes
Correct Answer: A
Rationale: The correct answer is A: Bone marrow. B cells mature in the bone marrow where they develop from hematopoietic stem cells. This process involves gene rearrangement and selection for self-tolerance. The bone marrow provides a microenvironment necessary for B cell development. Choices B, C, and D are incorrect because the thymus is where T cells mature, the spleen is involved in immune responses but not B cell maturation, and lymph nodes are sites for immune cell activation and proliferation but not B cell maturation.
In a patient with a CD4 count less than 200, the most important nursing assessment would include:
- A. Bowel movements.
- B. Urinary output.
- C. Fever.
- D. Blood pressure.
Correct Answer: C
Rationale: A CD4 count below 200 indicates advanced HIV infection (AIDS), making the patient highly susceptible to opportunistic infections. Fever is a key sign of infection and requires immediate attention. Bowel movements and urinary output are less urgent priorities in this context.
Which of the following is NOT true about live attenuated vaccines
- A. Usually effective at a single dose
- B. Expensive handling and storage
- C. Potential hazard due to reversion to a virulent form
- D. Able to induce only a humoral response
Correct Answer: D
Rationale: The correct answer is D: Able to induce only a humoral response. Live attenuated vaccines can induce both humoral and cellular immune responses, not just humoral. This is because they mimic natural infection, leading to a broader immune response.
A: Usually effective at a single dose - This is true for live attenuated vaccines, as they often provide long-lasting immunity with just one dose.
B: Expensive handling and storage - Live attenuated vaccines can be more cost-effective due to fewer doses needed, not expensive.
C: Potential hazard due to reversion to a virulent form - This is a concern with live attenuated vaccines, as there is a risk of the weakened virus reverting to a virulent form.