ATI RN
Questions on Immune System Questions
Question 1 of 5
What is the contribution of Th cells in T cell activation?
Correct Answer: B
Rationale: Th cells secrete IL-2 to boost CTL proliferation and memory ; killing is CTL's role, adhesion and MHC recognition are broader.
Question 2 of 5
Which is not a property of the red pulp within the spleen?
Correct Answer: A
Rationale: Red pulp filters blood with erythrocytes and macrophages , not lymph ; erythrocyte production is fetal, not adult.
Question 3 of 5
Epithelial surfaces provide the first line of defense against infection by the use of several types of mechanisms. One of the chemical mechanisms used by epithelia is:
Correct Answer: B
Rationale: Antimicrobial peptides are chemical defenses; tight junctions are physical, mucus and cilia are mechanical.
Question 4 of 5
The drawing in Figure Q4.12 shows antibodies bound to repetitive epitopes on the surface of a bacterial pathogen. Even though all of these epitopes are identical, not all of them have antibodies bound to them. The most likely explanation for this failure of antibodies to bind to every possible epitope on the surface of the pathogen is:
Correct Answer: C
Rationale: Steric hindrance limits binding to all epitopes; insufficient antibody , evasion , or dual-site binding are less likely.
Question 5 of 5
eyeball too short cause
Correct Answer: A
Rationale: An eyeball that is too short causes farsightedness (hyperopia) because light focuses behind the retina, making near objects blurry.