8- Lymph node VM Flashcards
Where are lymphocytes generated and become mature?
In the primary lymphatic organs (BM and thymus)
Where do lymphocytes mount an immune response?
Secondary lymphatic organce (lymph nodes)
What is the “mesh” support system of secondary lymphatic organisms? What is it composed of?
Stroma (made of reticular fibers)
What are the main cells of the lymph node parenchyma and where are they located?
- B cells (peripherally in follicles within the cortex)
- T cells and macrophages (in the paracortex and medulla)
Contrast the appearance of primary and secondary lymphoid follicles; why are they different?
- primary= uniform dark staining (consist mostly of naive B cells)
- secondary= lighly staining germinal ceneter surrounded by darker staining mantle zone (indicates B cells have been activated by the presence of a foreign antigen in the lymph fluid)
What is the functional significance of a germinal center in a lymph follicle?
A germinal center indicates that new B cells are being produced in response to an antigenic stimulus
What is the functional significance of high endothelial venules in the lymph node?
HEVs are the “conduit” by which lymphocytes enter and are sequestered within lymph nodes
When you palpate a patient’s cervical “swollen glands”, what are you really palpating? What is happening at the cellular level in these structures?
- Palpating lymph nodes that are enlarged and have triggered a pain response
- Nodes are enlarged due to reactive changes in the lymph node including:
- follicular hyperplasia (B cell proliferation forming germinal centers)
- paracortical hyperplasia (T cell proliferation)
- sinus histiocytosis (expanded sinuses)