The three types of connective tissue include collagen, reticular fibers, and elastin. The dermis only houses collagen and elastin fibers. Dense, closely-knitted collagen fibers make up the bulk of tendons and ligaments, while elastin fibers help control the blood pressure of vascular cells. Thick collagen fibers are also found in the reticular layer. In the papillary layer, there is a more thin distribution of collagen fibers.