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