<P> The cells of connective tissue include fibroblasts, adipocytes, macrophages, mast cells and leucocytes . </P> <P> The term "connective tissue" (in German, Bindegewebe) was introduced in 1830 by Johannes Peter Müller . The tissue was already recognized as a distinct class in the 18th century . </P> <P> Connective tissue can be broadly subdivided into connective tissue proper, and special connective tissue . Connective tissue proper consists of loose connective tissue and dense connective tissue (which is further subdivided into dense regular and dense irregular connective tissues .) Loose and dense connective tissue are distinguished by the ratio of ground substance to fibrous tissue . Loose connective tissue has much more ground substance and a relative lack of fibrous tissue, while the reverse is true of dense connective tissue . Dense regular connective tissue, found in structures such as tendons and ligaments, is characterized by collagen fibers arranged in an orderly parallel fashion, giving it tensile strength in one direction . Dense irregular connective tissue provides strength in multiple directions by its dense bundles of fibers arranged in all directions . </P> <P> Special connective tissue consists of reticular connective tissue, adipose tissue, cartilage, bone, and blood . Other kinds of connective tissues include fibrous, elastic, and lymphoid connective tissues . New vascularised connective tissue that forms in the process of wound healing is termed granulation tissue . Fibroblasts are the cells responsible for the production of some CT . </P>

List the three major groups of connective tissue