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