ATI RN
Lymphatic System Practice Questions Questions
Question 1 of 5
What is the main function of the thymus?
Correct Answer: D
Rationale: The thymus eliminates self-reactive T cells via selection ; Treg generation is secondary, not B cells or activation .
Question 2 of 5
The majority of vaccines work by eliciting pathogen-specific antibodies that circulate in our bodies and protect us in the event that we are later exposed to that specific pathogen. For most viruses and bacterial toxins that we are vaccinated against, these pre-existing antibodies are protective because:
Correct Answer: A
Rationale: Antibodies neutralize viruses/toxins by blocking cell entry ; liver transport , lysis , or mucus aren't primary mechanisms.
Question 3 of 5
In healthy adults, neutrophils represent approximately half of their white blood cells. During a bacterial infection, this number often rises to >80%. One factor contributing to this rise is:
Correct Answer: C
Rationale: Bone marrow releases neutrophils during infection; tissues , proliferation (B/C), or monocyte differentiation don't explain the rise.
Question 4 of 5
The extensive polymorphism of MHC genes in the population is thought to represent an evolutionary response to outflank the evasive strategies of pathogens. This polymorphism makes it difficult for pathogens to eliminate all potential MHC binding epitopes from their proteins. Based on this reasoning, it would seem advantageous for each individual to encode more than three different MHC class I and three different MHC class II genes per chromosome copy. If some individuals in the population had MHC loci that encoded 10 different MHC class I and 10 different MHC class II genes, the T cell repertoire in those individuals would likely be:
Correct Answer: C
Rationale: More MHC alleles reduce T-cell diversity via stricter thymic selection; not more diverse , rare pathogens , or just alloreactive .
Question 5 of 5
Which of the following wander through the interstitial fluid and consume any bacteria and virus-infected cells they encounter?
Correct Answer: C
Rationale: Macrophages are phagocytic cells that patrol interstitial fluid, engulfing bacteria and infected cells, unlike erythrocytes (red blood cells), leukocytes (general white cells), or interferons (antiviral proteins).