The industrial nurse examines an employee who complains of right shoulder pain on abduction. He points with one finger to the exact location of the pain and mentions that he won a racquetball tournament yesterday. The nurse suspects the employee is suffering from which problem?

Correct Answer: B

Rationale: The correct answer is B: Bursitis. The employee's complaint of shoulder pain on abduction, localized pain with a specific trigger (racquetball tournament), and no mention of trauma or instability suggest an inflammatory condition like bursitis. The other choices are incorrect because a rotator cuff tear typically presents with weakness, dislocation with a history of trauma and visible deformity, and subluxation with recurrent episodes of partial dislocation.

Correct Answer: B

Rationale: The correct answer is B: The shape of antigens. T cells recognize antigens based on their shape, specifically the conformational structure of the antigen. T cell receptors interact with the surface of antigens, forming a complex based on the shape complementarity. This interaction is crucial for T cell activation and immune response. A: Linear peptides - While T cells can recognize linear peptides presented by MHC molecules, the primary mode of recognition is through the shape of antigens. C: Buried epitopes - T cells typically recognize epitopes displayed on the surface of antigens rather than buried within the structure. D: Soluble antigens - T cells can recognize both soluble and membrane-bound antigens, but the key factor is the shape rather than the solubility of the antigen.

Correct Answer: C

Rationale: The correct answer is C: Paracortex. Naïve T cells circulate through the blood and lymphatic system until they encounter antigens presented by activated dendritic cells in the paracortex of lymph nodes. The paracortex is the region where T cell activation and proliferation occur, leading to an immune response. The subcapsular sinus (A) is primarily involved in filtering lymph fluid, the cortex (B) contains B cell follicles, and the medulla (D) contains plasma cells and macrophages. Thus, the paracortex is the specific site of interaction between naïve T cells and activated dendritic cells in lymph nodes.

Correct Answer: D

Rationale: The correct answer is D. Tamiflu interferes with the function of Neuraminidase (N), not Hemagglutinin (HA). HA binds to sialic acid on cell surface molecules, not N. N's function is to release new viral particles. Both HA and N undergo antigenic drift. Therefore, choice D is incorrect as it misrepresents the mechanism of action of Tamiflu.

Correct Answer: D

Rationale: Firstly, Lysozyme is a Microbe-Associated Molecular Pattern (MAMP), not a protein. MAMPs are molecules recognized by the innate immune system to trigger immune responses. Lysozyme is not specific to protecting the eye (A), binding membranes (B), or digesting cell walls (C). Therefore, the correct answer is D.