All connective tissues, including the loose variety, are composed of two basic components: intercellular matrix and cells. The types and relative proportions of each determine the kind of connective tissue. The intercellular matrix of loose connective tissue is composed of various fibers and ground substance. A. Connective tissue fibers. There are three types of fibers in the intercellular matrix of connective tissue: (1) collagen fibers, (2) reticular fibers, and (3) elastic fibers. Collagen fibers. The most prevalent protein in the body is collagen.