ATI RN
Lymphatic System Questions and Answers PDF Questions
Question 1 of 5
Emil von Behring developed the 'serum therapy', a treatment that offered protection against diphtheria. The basis for this therapy was the immunization of horses with diphtheria toxin, after which the serum of the horses was taken and used to treat diphtheria-infected individuals. Paul Ehrlich postulated that side-chains were responsible for this effect. What did those side-chains turn out to be?
Correct Answer: B
Rationale: Serum therapy relies on antibodies produced in horses that bind and neutralize diphtheria toxin; complement and phagocytes play roles in immunity but aren't the primary 'side-chains' Ehrlich identified.
Question 2 of 5
What is the problem with the short cytoplasmic tails of TCRs?
Correct Answer: B
Rationale: Short TCR tails can't signal activation ; CD3 compensates; antigen recognition and co-receptor binding are intact.
Question 3 of 5
How do T cells with high affinity for self-antigens get eliminated?
Correct Answer: C
Rationale: High self-affinity T cells are removed by negative selection ; anergy is peripheral, activation and positive selection retain cells.
Question 4 of 5
The thoracic duct empties directly into the vein
Correct Answer: B
Rationale: The thoracic duct empties into the left subclavian vein at the jugular-subclavian junction.
Question 5 of 5
When complement proteins are covalently deposited onto the surface of a bacterium, this can sometimes lead to direct lysis of the bacterium. However, more commonly, the deposition of complement proteins onto the bacterial surface does not directly harm the bacterium. Instead, these complement proteins aid in bacterial elimination by:
Correct Answer: D
Rationale: Complement (e.g., C3b) enhances phagocytosis via complement receptors ; Fc receptors are antibody-related, not replication or B-cell stimulation .