Collagen

See connective tissueThe various organs of the body are made up of different types of tissue, according to the function that the organ fulfils. Brain, bone, muscle, skin, lung and liver tissue all appear very different under the microscope but they all contain variable amounts of connective tissue, essentially holding the remaining tissue in place. Structures such as tendons and ligaments, which have a purely “holding together” function are made up almost entirely of connective tissue. Collagen and elastin are the principal forms of connective tissue..