<human>: What is the difference between a hyaluronic acid and a hyaluronan?
<bot>: A hyaluronic acid is a type of glycosaminoglycan, while a hyaluronan is a polysaccharide. Hyaluronic acids are found in the extracellular matrix of many tissues, including skin, cartilage, and synovial fluid. They are also found in high concentrations in the eye's vitreous humor. Hyaluronans are linear polymers of repeating disaccharides that form an important component of the extracellular matrix.