Immunology USMLE Step 1 Quiz with complete solutions | Latest 2023/2024

Immunology USMLE Step 1 Quiz with complete solutions | Latest 2023/2024 Lymph node anatomy -- - derived from *mesenchymal cells* - *follicles: B cell* proliferation + localization (outer cortex) - *paracorTex: T cells* - *inner cortex / paracortex*: *thymus dependent (di george!)* - medullary sinus: macrophages (*filter blood*) - *Medullary cords: plasma cells* Cytotoxic T cell response - from viruses! -- - extreme cellular immune response (immunoCOMPETENT people) - triggered by *viral infection* - enlargement of *paracortex* in lymph nodes (produce T cells!) Lymph drainage -- - Thoracic duct drains @ junction of left subclavian trunk + internal jugular v - Lymphatic fluid is high in TGs (from chylomicrons) Peyer's patches -- - Un-encapsulated lymphoid tissue - *lamina propria / submucosa of ILEUM* - terminal ileum, deals w/ bact *reflux from colon* - M cells on the outer edges - B cells stimulated in germinal centers Immuno overview -- Primary lymphoid organs: bone marrow and thymus Secondary lymphoid organs Lymph nodes Spleen MALT Cutaneous associated lymphoid tissue Appendix M cells M cells -- - found in mucous membranes (MALT) - flattened epithelial cells lacking microvilli (*can't absorb*) - *pull antigen from lumen* of gut + transcytose it to other side of cell - *Deep pocket on basilar side* - basal side: docking station for dendritic cells, b cells (*secrete IgA*), t cells, macrophages - "What's the news of the gut?" Mucosa associated lymphoid tissue (MALT) -- - lymphoid follicles!! - GALT - Gut associated - M cells - Peyer's Patches - BALT - bronchus associated - NALT - nasal associated - genitourinary tract, tonsils, adenoids Breast lymph drainage -- - lateral breast --> axillary nodes To which lymph nodes do the 1) sigmoid colon and 2) rectum drain? -- Where can B cells and T cells be found in the lymph nodes? -- What are the different sinuses that can become infected and cause sinusitis? -- - max = most common - 2nd = frontal - ethmoid (between eyes) - Sphenoid = deeper (behind eyes) MHC I and MHC II -- - HLA = human leukocyte antigen! HLA-A3 -- Hemochromatosis