Nokea
Afferent lymphatic vessels do not
- A. Transport antigens from tissues to LN
- B. Enter LN at more than one site
- C. Transport antigens from blood to LN
- D. Connect tissues to secondary lymphoid organs
Correct Answer: C
Rationale: Rationale: Afferent lymphatic vessels transport lymph containing antigens from tissues to lymph nodes (LN). Option C is correct because afferent lymphatics do not transport antigens directly from the blood to LN. Other choices are incorrect because afferent lymphatics enter LN at multiple sites (B), transport antigens from tissues to LN (A), and connect tissues to secondary lymphoid organs (D).
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Which of the following immunoglobulins is present normally in plasma at the highest concentration?
- A. IgG
- B. IgM
- C. IgA
- D. IgD
Correct Answer: A
Rationale: The correct answer is A: IgG. IgG is the most abundant immunoglobulin in plasma, comprising around 75% of total immunoglobulins. It is produced in response to infections and provides long-term immunity. IgM is the first antibody produced in response to an infection, but its concentration decreases over time. IgA is mainly found in mucosal areas and secretions. IgD is present in small amounts and its function is not fully understood. Thus, IgG is the correct answer due to its high concentration in plasma and important role in long-term immunity.
Which complement pathway is triggered by mannose-binding lectin (MBL)?
- A. Alternative pathway
- B. Classical pathway
- C. Lectin pathway
- D. Terminal pathway
Correct Answer: C
Rationale: The correct answer is C, Lectin pathway. MBL recognizes pathogen-associated molecular patterns containing mannose, initiating the lectin pathway. MBL binds to mannose on microbial surfaces, activating MBL-associated serine proteases, leading to the formation of the C3 convertase. This triggers the rest of the complement cascade.
A: Alternative pathway is triggered by spontaneous hydrolysis of C3, not by MBL.
B: Classical pathway is activated by antigen-antibody complexes, not MBL.
D: Terminal pathway (also known as the membrane attack complex) is the final step of all complement pathways, not specifically triggered by MBL.
The physician plans to prescribe trastuzumab (Herceptin) for the patient with breast cancer. What testing will the physician order before prescribing this medication?
- A. HER2 protein levels
- B. BRCA2 gene mutation
- C. BRCA1 gene mutation
- D. Stage II cancer identification
Correct Answer: A
Rationale: Trastuzumab targets HER2-positive breast cancers, so HER2 protein level testing is essential to determine eligibility.
What is the process called when a specific lymphocyte binds its antigen and proliferates?
- A. Clonal deletion
- B. Clonal selection
- C. Antigen presentation
- D. Cytokine signaling
Correct Answer: B
Rationale: The correct answer is B: Clonal selection. During clonal selection, a specific lymphocyte recognizes its specific antigen, binds to it, and undergoes proliferation to generate a large population of identical cells to combat the antigen efficiently. This process ensures an effective immune response.
Incorrect choices:
A: Clonal deletion - This process involves the elimination of self-reactive lymphocytes to prevent autoimmunity, not the proliferation of antigen-specific lymphocytes.
C: Antigen presentation - This is the process by which antigens are displayed to immune cells for recognition, not the proliferation of lymphocytes.
D: Cytokine signaling - While cytokines play a role in immune responses, they are not directly involved in the proliferation of lymphocytes in response to specific antigens.
Priority Decision: On assessment of a central venous access device (CVAD) site, the nurse observes that the transparent dressing is loose along two sides. What should the nurse do immediately?
- A. Wait and change the dressing when it is due
- B. Tape the two loose sides down and document
- C. Apply a gauze dressing over the transparent dressing and tape securely
- D. Remove the dressing and apply a new transparent dressing using sterile technique
Correct Answer: D
Rationale: Loose dressings increase infection risk; replacing the dressing with sterile technique ensures safety.