This class of primary tissue supports other tissues and connects all of the body's tissues and organs together.

• Cells tend to be widely separated among the masses of fibers and ground substances.
• The principal functions of these tissues are structurally expressed in the nature and densities of the fibers and ground substance which are collectively termed the extracellular matrix.
• The fibers, consisting particularly of collagen or elastin, are responsible for the tensile strength and elasticity of the bindings.
• The ground substance, which is substantially made up of hydrated proteoglycans, provides the medium through which dissolved substances pass from capillaries to cells and back.

Because supporting/connective tissues show great diversity in density and regularity of fibers and cells, rigid classification is not possible. Nonetheless, terms such as

• Loose (or areolar) CT (shown at right),
• Dense irregular CT, and
• Dense regular CT are still widely used and you should know what is meant by these types of CT proper.

Learning objectives and getting started.