ATI RN
Lymphatic System Quiz Questions Questions
Question 1 of 5
Which of these does not belong with the others?
Correct Answer: A
Rationale: Thymus is a primary lymphoid organ; lymph node , sinus , and nodule are secondary lymphoid structures.
Question 2 of 5
Many different viruses encode proteins that function to down-regulate MHC class I expression on host cells following infection with the virus. This immune evasion mechanism allows the virus to hide from CD8 T lymphocytes that normally detect virus-infected cells by using their T cell antigen receptor to recognize viral peptides bound to MHC class I proteins on the surface of the infected cell. To counteract this immune evasion strategy, NK cells have:
Correct Answer: A
Rationale: NK cells use inhibitory MHC I receptors ; low MHC I activates them, not activating MHC or capsid (C/D) receptors.
Question 3 of 5
The TCR signaling module leading to transcription factor activation is dependent on the enzyme phospholipase-C-γ (PLC-γ). The mechanism by which PLC-γ activates multiple transcription factors is by:
Correct Answer: A
Rationale: PLC-γ produces IP3 and DAG , activating transcription factors; not direct cleavage , nuclear diffusion , or chaperones .
Question 4 of 5
What substance, produced by virus-infected cells, diffuses to neighboring cells to help them fight a viral infection?
Correct Answer: B
Rationale: Interferon is produced by virus-infected cells and signals nearby cells to enhance antiviral defenses, unlike lysozyme (antibacterial), histamine (inflammation), or interleukin-2 (immune activation).
Question 5 of 5
Which of the following distinguishes the secondary immune response from the primary immune response?
Correct Answer: B
Rationale: The secondary response, driven by memory cells, is faster and stronger than the primary, both being specific and involving B/T cells.