Which of the following is not an antigen presenting cell?
Dendritic cell
B cell
Macrophage
all of the above are APCs
NK cell
The Correct Answer is E
A. Dendritic cell: Dendritic cells are professional antigen-presenting cells (APCs) that capture antigens, process them, and present them on MHC molecules to T lymphocytes, initiating adaptive immune responses.
B. B cell: B cells can function as APCs by internalizing antigens via their B cell receptor, processing them, and presenting antigen fragments on MHC II molecules to helper T cells.
C. Macrophage: Macrophages are APCs that engulf pathogens and present antigen fragments to T cells, linking innate and adaptive immunity.
D. All of the above are APCs: While dendritic cells, B cells, and macrophages are APCs, this statement is misleading because it ignores the presence of non-APCs like NK cells.
E. NK cell: Natural killer (NK) cells are not antigen-presenting cells. They are cytotoxic lymphocytes of the innate immune system that destroy virus-infected and tumor cells without presenting antigens to T cells.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is C
Explanation
A. Tunica intima:The tunica intima is the innermost layer composed mainly of endothelial cells that provide a smooth surface to reduce friction and regulate vessel tone chemically. While it plays roles in coagulation and permeability, it does not generate the force needed to maintain blood pressure. Its structure is not designed for active contraction or pressure regulation.
B. Tunica externa:The tunica externa is the outer connective tissue layer that protects the vessel and anchors it to surrounding structures. Although it provides structural support, it does not contain the smooth muscle necessary to adjust vessel diameter. Without this contractile ability, it cannot directly influence blood pressure.
C. Tunica media:The tunica media contains smooth muscle fibers and elastic tissue that allow vessels-especially arteries-to constrict or dilate. These changes in vessel diameter regulate peripheral resistance, which is a major determinant of blood pressure. Its contractile strength makes it the primary structural layer responsible for maintaining and adjusting blood pressure.
D. Subendothelial:The subendothelial layer is a thin connective tissue region beneath the endothelium. It provides minor structural support but lacks smooth muscle or elastic fibers needed for active regulation. Because it cannot constrict or dilate, it plays little to no role in controlling blood pressure.
Correct Answer is D
Explanation
A. The cephalic vein:The cephalic vein is a major superficial vein of the upper limb, running along the lateral aspect of the arm and forearm. It drains into the axillary vein and is commonly used for venipuncture.
B. The median cubital vein:The median cubital vein is a superficial vein located in the cubital fossa of the elbow. It connects the cephalic and basilic veins and is frequently used for blood draws.
C. The basilic vein:The basilic vein is a large superficial vein of the medial arm and forearm. It eventually drains into the axillary vein and is part of the upper limb venous system.
D. The great saphenous vein:The great saphenous vein is a superficial vein of the lower limb, running along the medial aspect of the leg and thigh. It is not part of the upper limb venous system.
E. Median antebrachial vein:The median antebrachial vein runs along the anterior forearm and drains into either the basilic or cephalic veins. It is a vein of the upper limb.
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