ATI RN
PAL Histology Lymphatic System Lab Practical Question 1 Questions
Question 1 of 5
venous sinus open into
Correct Answer: B
Rationale: Venous sinuses open into red pulp veins.
Question 2 of 5
Choose the correct statement about pharyngeal tonsil:
Correct Answer: B
Rationale: Pharyngeal tonsil has pseudostratified columnar epithelium with goblet cells ; it lacks crypts , is in nasopharynx , protects respiratory system .
Question 3 of 5
Which complement protein forms a complex that functions as a chain saw to slice other C3 proteins?
Correct Answer: B
Rationale: C3bBb (convertase) cleaves C3 into C3a and C3b ; C1 initiates classical, C3 is cleaved, C4 is upstream.
Question 4 of 5
What is the function of CD4 and CD8 co-receptors?
Correct Answer: C
Rationale: CD4/CD8 enhance TCR signaling via CD3 ; they stabilize MHC binding (A indirectly), not antigen binding .
Question 5 of 5
Which cells in the thymus examine T cells for MHC restriction and tolerance of self during positive selection?
Correct Answer: C
Rationale: Cortical thymic epithelial cells test T cells for MHC restriction in positive selection ; medullary cells handle negative selection.