05 Spleen
Lymphoid Organs
- Cortex: white, contains follicle
- Paracortex: T cells
- Medulla with cords and sinus
- Afferent lymph goes through the 3 layers, exit at 1 efferent vessel
- APC process free antigens
Cortex
- dendritic cell like velcro picking up antigens that allow B cell to react
- 4: follicle
- 3: white, germinal center, thus secondary follicle
Paracortex
- HEV: spaces between endothelium to allow B and T from blood to enter lymph
Medulla
Spleen
- not lymph filter
- filters blood
- everything in blood enters spleen
- first from artery to white pulp (white)
- then blood moves through red section, red pulp
- eventually back to splenic vein
White Pulp
Red Pulp
- endothelium with barrel hoop membrane. Still large enough for blood to pass through
- less complement activity because needs IgG and IgM for binding Fc
- antibody binding leads to MAC and c3b formation
- macrophage binds to antibody and c3b, phagocytosis
- malaria/babesia: infected RBC can't be cleared
- ITP: low platelets. Take out spleen to increase platelet
- spherocytosis: take spleen out, less destruction of anemia
- Sickle cell: so many abnormal RBC that damages spleen when removed
- target cells usually cleared by spleen
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