FOR A PDF DOCUMENT OF THIS INFORMATION, CLICK: http://content.lib.auburn.edu/cdm/singleitem/collection/vetmed1/id/985 - GROUND SUBSTANCE:
The formed elements (e.g., fibers) of connective tissue are embedded in an amorphous (means-no form) material . GROUND SUBSTANCE is a sol-like, loose, flexible, and/or soft in ordinary connective tissues.
GROUND SUBSTANCE (AMORPHOUS MATERIAL) in connective tissue fills up the gaps that are not occupied by cells and fibers and also provides the site for tissue fluid. It is SHAPELESS and is the area through which metabolites must pass from cell to bloodstream or vice versa. The amorphous ground substance is the SITE WHERE INFLAMMATION OCCURS, acts as a BARRIER TO BACTERIA, and provides the HOMEOSTATIC ENVIRONMENT for cells. Also, it is the site where growth, differentiation, regeneration, and aging occurs.
The GROUND SUBSTANCE is made up of a family of compounds referred to as GLYCOSAMINOGLYCANS (GAG) (mucopolysaccharides MPS). GAG is an all encompassing term which refers to compounds made up of carbohydrates and amino acids. THERE ARE TWO GENERAL GROUPS (1) SIMPLE ORGANIC ACIDS (HYALURONIC ACID) OR (2) SULFURIC ACID GROUPS (CHONDROITIN SULFATE TYPES). THE DOMINANCE OF EITHER COMPOUND DICTATES THE CHARACTERISTIC OF THAT TISSUE. THAT IS, WHEN HYALURONIC ACID IS THE MOST ABUNDANT, THE TISSUE IS SOFT AND PLIABLE (e.g., SKIN, CONNECTIVE TISSUE IN ORGANS OR GLANDS), OR IF THE SULFATED COMPOUND IS ABUNDANT THE TISSUE IS FIRM (e.g., CARTILAGE, BONE). If you obtain all the GAG from any tissue, you would find many types of GAG functioning in harmony. You would not find any single group or type of GAG in any one tissue.
PROTEOGLYCAN is a complex macromolecular structure that consists of a core protein and sulfated glycosaminoglycan, which are carbohydrate chains formed by repeating disaccharides. Proteoglycan aggregates are formed by the proteoglycan macromolecule linked to hyaluronic acid.
The ground substance DOES NOT include TISSUE FLUID! If pressure is applied to CT the ground substance cannot be squeezed out. What you would see is the tissue fluid being extracted.