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 are small clumps of immune cells that act as filters for the lymphatic system. The lymphatic system runs throughout the body (like the circulatory (blood) system) and carries fluid and cells. The lymph nodes in the underarm (the axillary lymph nodes) are the first place breast cancer is likely to spread.ymph nodes are small clumps of immune cells that act as filters for the lymphatic system. The lymphatic system runs throughout the body (like the circulatory (blood) system) and carries fluid and cells. The lymph nodes in the underarm (the axillary lymph nodes) are the first place breast cancer is likely to spread.