Loose connective tissue pervades all parts of the body. The tissue makes up the framework for such organs as the liver, bone marrow, and lymph glands. Loose connective tissue's other functions include supporting, surrounding, or connecting non-connective tissue layers. For example, loose connective tissue holds internal organs in place in the body cavity, lines the heart and abdominal cavities, binds individual organs or parts of organs together, and attaches the skin to the tissues underneath. Loose connective tissue possesses large quantities of all the connective tissue cell types. This may explain how loose connective tissue is able to play so many different roles in so many different settings throughout the body. The characteristic loose, irregular make-up of the tissue's fibers and the large amount of ground substance found in loose connective tissue make the tissue very flexible and, consequently, permits movement among the non-connective tissues it connects.
Dense connective tissue has a much smaller quantity of connective tissue cells relative to loose connective tissue. Dense connective tissue consists of very compactly grouped fibers and has much less ground substance than loose connective tissue. Two permutations of dense connective tissue exist. As an interwoven network of irregularly-arranged fibers, dense connective tissue forms the sheath over bones and the dermis of the skin. As parallel bundles of regularly-arranged fibers, dense connective tissue forms tendons which connect muscle to bone and ligaments which
