Types of collagen

Types of Collagen Currently, there are over 22 different types of collagen identified, Type I to Type XXV, distributed in every organ and tissue of the body. The functional versatility of collagen is well documented from structural scaffolding for new tissue growth to possessing chemotactic properties that regulate cellular functions. There are seven collagen molecules that have recently been discovered but their function is still a mystery. Key characteristics of the five most documented collagen types:
Type	Location	Function
I	Extracellular; skin, tendon, bone, teeth, scar tissue. Thick fibrils and fibers	Strength and integrity of tissue, chemotactic for macrophage and fibroblast, adhesive properties, hydrophillic
II	Extracellular; cartilage and vitreous humor. Thin fibrils	Joint mobility and shock absorption
III	Extracellular; skin, muscle, blood vessels, lungs, granulation tissue Intermediate-sized fibrils	Allows for distendibility and provides strength and integrity to tissue
IV	Intracellular; basement membrane and lamina	Component forming network Mesh-like scaffold for filtration
V	Extracellular; found in all tissue and around cells as a cytoskeleton	Similar to Type III collagen
The composition of collagen is similar across the different types yet each type has unique characteristic. The types are grouped according to their physical structure, for example, Type I collagen is long and linear while Type IV collagen is in a mesh-like form. Type I collagen is used to build new tissue so needs be in a form that can be bundled together to build mass and fill in skin defects of wounds. Type IV can be found in the basement membrane of the dermis and needs to allow filtration of nutrients through it to nourish the dermis layer of the skin.