Definition of transient ischemic attack. : a brief episode of cerebral ischemia that is usually characterized by temporary blurring of vision, slurring of speech, numbness, paralysis, or syncope and is often predictive of a serious stroke âabbreviation TIA âcalled also ministroke.
Germinal centers are an important part of the B cell humoral immune response, acting as central factories for the generation of affinity matured B cells specialized in producing improved antibodies that effectively recognize infectious agents, and for the production of durable memory B cells.nce these B cells have stopped proliferating, they migrate to the light zone where they are known as centrocytes, and are subjected to selection by follicular helper T (TFH) cells in the presence of follicular dendritic cells (FDCs).
Lymph nodes serve two major functions in the body. They filter lymph and assist the immune system in building an immune response. Lymph is a clear fluid that comes from blood plasma that exits blood vessels at capillary beds.This fluid becomes the interstitial fluid that surrounds cells.-cells and T-cells are lymphocytes found in lymph nodes and lymph tissues. When B-cell lymphocytes become activated due to the presence of a particular antigen, they create antibodies that are specific to that specific antigen. The antigen is tagged as an intruder and labeled for destruction by other immune cells.