ATI RN
Immune System Multiple Choice Questions and Answers Questions
Question 1 of 5
The skin and bodily secretions provide the first line of defense against infection. One response in this category that is common during upper respiratory virus infections is:
Correct Answer: C
Rationale: Mucus production traps pathogens in the respiratory tract as a first-line defense; antibodies and WBC infiltration are later, saliva is less specific.
Question 2 of 5
The cellular distribution of MHC class I versus MHC class II molecules is quite different, with MHC class II molecules generally expressed on a very limited set of cell types. This is because:
Correct Answer: B
Rationale: MHC II on APCs (macrophages, B cells) allows CD4 T-cell help ; CD8 killing or DC focus aren't the reason.
Question 3 of 5
Auxin hormones act as
Correct Answer: D
Rationale: Auxins promote seedling elongation, are transported downward (polar transport), and affect root elongation at lower concentrations. All options are correct.
Question 4 of 5
The two main functions of the lymphatic system are
Correct Answer: D
Rationale: The lymphatic system returns interstitial fluid to blood and combats infections via lymph nodes and organs, not coagulation or hormone production.
Question 5 of 5
Which of the following is an effect of interleukin-2?
Correct Answer: A
Rationale: Interleukin-2, from helper T cells, promotes T cell proliferation, not mast cell histamine release, APC stimulation, or macrophage phagocytosis.