- 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:
- The Cortex contains lymphocytes (mostly B-cells), macrophages & follicular dendritic cells arranged in primary follicles.
- It is innermost layer of lymph node
- 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".