Lymph node

  • Lymph nodes are encapsulated bean-shaped structures containing a reticular network placed with lymphocytes, macrophages & dendritic cells.
  • The overall architecture of a lymph node supports an ideal micro environment for lymphocytes to effectively encounter and respond to trapped antigens.
  • The lymph node can be divided into three roughly concentric regions based on morphology:

Cortex:

  • The Cortex contains lymphocytes (mostly B-cells), macrophages & follicular dendritic cells arranged in primary follicles.
  • This cortex region some times referred to as "Thymus-independent area.lymph node

Medulla:

  • It is innermost layer of lymph node

Para-cortex:

  • Beneath the cortex, which is populated largely by T-Lymphocytes and also contains interdigitating dendritic cells thought to have migrated from tissues to the node.
  • These interdigitating dendritic cells express high levels of class n MHC molecules, which are necessary for presenting antigen to TH-cells.
  • These paracortex regions sometimes referred to as a "Thymus dependent area".

lymph node LS

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