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).
The stratum germinativum is the deepest layer of the epidermis. It is also referred to as the basal layer of the skin. The epidermis is another name for the outermost layer of skin in humans as well as other mammals. The primary function of this region is to assist in the regeneration of the epidermis.he type of cells provided to the epidermis by the stratum germinativum are known as germinal cells. A germinal cell is simply a cell from which other cells are derived. The germinal cells developed in this layer are kept separate from the dermis by a thin membrane.