TABLE Types of Collagen, Composition, Location, and Function 6.2 Type Compositiona Location Functions I [ 1(I)]2 2(I) Connective tissue of skin, bone, tendon, Provides resistance to force, ligaments, dentin, sclera, fascia, and tension, and stretch organ capsules (accounts for 90% of body collagen) II [ 1(II)]3 Cartilage (hyaline and elastic), Provides resistance to notochord, and intervertebral disk intermittent pressure III [ 1(III)]3 Prominent in loose connective Forms reticular fibers, arranged tissue and organs (uterus, liver, spleen, as a loose meshwork of thin kidney, lung, etc.); smooth muscle; fibers, provides a supportive endoneurium; blood vessels; and scaffolding for the specialized fetal skin cells of various organs and blood vessels. IV [ 1(IV)]2 2(IV) or Basal laminae of epithelia, kidney Provides support and filtration 3(IV) 4(IV) 5(IV) or glomeruli, and lens capsule barrier [ 5(IV)]2 6(IV) V [ 1(V)]2 2(V) or Distributed uniformly throughout Localized at the surface of type I 1(V) 2(V) 3(V) connective tissue stroma; may be collagen fibrils along with type XII related to reticular network and XIV collagen to modulate biomechanical properties of the fibril VI [ 1(VI)]2 2(VI) or Forms part of the cartilage matrix Attaches the chondrocyte to the 1(VI) 2(VI) 3(VI) immediately surrounding the matrix; covalently bound to type I chondrocytes collagen fibrils VII [ 1(VII)]3 Present in anchoring fibrils of skin, Secures basal lamina to connective eye, uterus, and esophagus tissue fibers VIII [ 1(VIII)]2 2(VIII) Product of endothelial cells Facilitates movement of endothelial cells during angiogenesis IX 1(IX) 2(IX) 3(IX) Found in cartilage associated with Stabilizes network of cartilage type II collagen fibrils type II collagen fibers by interaction with proteoglycan molecules at their intersections X [ 1(X)]3 Produced by chondrocytes in the Contributes to the bone mineral-zone of hypertrophy of normal ization process by forming growth plate hexagonal lattices necessary to arrange types II, IX, and XI collagen within cartilage XI [ 1(XI)]2 2(XI) or Produced by chondrocytes; Regulates size of type II collagen 1(XI) 2(XI) 3(XI) associated with type II collagen fibrils, fibrils; it is essential for cohesive forms core of type I collagen fibrils properties of cartilage matrix XII [ 1(XII)]3 Isolated from skin and placenta; Localized at the surface of type I abundant in tissues in which collagen fibrils along with type V mechanical strain is high and XIV collagen to modulate biomechanical properties of the fibril XIII [ 1(XIII)]3 An unusual transmembrane collagen Associated with the basal lamina detected in bone, cartilage, intestine, along with type VII collagen skin, placenta, and striated muscles continued next page