fibroblast reticular cell A fibroblast that synthesizes collagen and uses it to produce reticular fibers, thus providing structural support. Reticular cells are found in many organs, including the spleen, lymph nodes and kidneys. Subtypes of reticular cells include epithelial, mesenchymal, and fibroblastic reticular cells. Fibroblastic reticular cells are involved in directing B cells and T cells to specific regions within a tissue, whereas epithelial and mesenchymal reticular cells are associated with certain areas of the brain. reticulum cell FMA:62877