Nokea
What type of receptor is found on B cells for antigen recognition?
- A. T cell receptor (TCR)
- B. B cell receptor (BCR)
- C. Fc receptor
- D. Complement receptor
Correct Answer: B
Rationale: The correct answer is B because B cells express B cell receptors (BCR) on their surface for recognizing antigens. BCRs consist of immunoglobulin molecules that bind specifically to antigens. T cell receptors (A) are found on T cells, not B cells. Fc receptors (C) bind to the Fc region of antibodies, while complement receptors (D) recognize complement proteins, not antigens. Therefore, the BCR is the specific receptor on B cells for antigen recognition.
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Which of the following statements concerned with multiple sclerosis (MS) is correct?
- A. Genetic factors seem to play a role in predisposition to develop MS
- B. Predisposition to develop MS does not seem to have an environmental component
- C. MS is more common in Central and South America than in North America
- D. The disease seems to be mediated primarily by autoantibodies
Correct Answer: A
Rationale: Rationale: Option A is correct because genetic factors have been identified as playing a role in predisposition to develop MS. Studies have shown a higher risk among individuals with family history. Option B is incorrect because environmental factors, such as vitamin D levels and viral infections, are known to influence MS development. Option C is incorrect as MS is more prevalent in North America and Europe. Option D is incorrect because MS is primarily mediated by T-cell responses, not autoantibodies.
What is the primary effector cell in delayed-type hypersensitivity?
- A. Mast cells
- B. T cells
- C. Neutrophils
- D. B cells
Correct Answer: B
Rationale: The primary effector cell in delayed-type hypersensitivity is T cells. T cells play a crucial role in initiating and orchestrating the immune response in delayed hypersensitivity reactions. Upon exposure to the antigen, T cells are activated and release cytokines that recruit and activate macrophages, leading to the inflammatory response characteristic of delayed-type hypersensitivity. Mast cells are involved in immediate hypersensitivity reactions mediated by IgE. Neutrophils are primarily involved in acute inflammation and combating bacterial infections. B cells are responsible for antibody production in humoral immunity, not in delayed hypersensitivity reactions. Therefore, the correct answer is B: T cells.
Which patient is at the greatest risk for developing pressure ulcers?
- A. A 42-year-old obese woman with type 2 diabetes
- B. A 78-year-old man who is confused and malnourished
- C. A 30-year-old man who is comatose following a head injury
- D. A 65-year-old woman who has urge and stress incontinence
Correct Answer: C
Rationale: Comatose patients are at significant risk for pressure ulcers due to prolonged immobility, impaired sensation, and compromised circulation.
In a client with AIDS,a CD4 cell count above ______ mm³ would indicate that antiretroviral therapy is being effective.
- A. 250
- B. 1000
- C. 500
- D. 275
Correct Answer: C
Rationale: A CD4 count above 500 mm³ indicates a strong immune response and effective antiretroviral therapy.
Choose the best definition for effector T cells. They are cells that
- A. Have never seen their specific antigen
- B. Have just seen their specific antigen and start to proliferate
- C. Have been energized
- D. Have been activated, expanded and are able to kill or help other cells
Correct Answer: D
Rationale: Effector T cells are fully activated, expanded, and capable of carrying out their functions, such as killing infected cells or assisting in immune responses. The correct choice (D) accurately describes the characteristics of effector T cells. They are not naïve cells (A), as they have encountered their specific antigen. They are not just starting to proliferate (B), as they have already undergone extensive proliferation. They have not only been energized (C), but have also completed the necessary steps for full activation and functionality.