This image shows collagen, a fibrous protein that is the main component of the extracellular matrix (ECM). Collagen is a strong, rope-like molecule that forms stretch-resistant fibers. The most abundant protein in our body, collagen makes up about a quarter of our total protein mass. Among its many functions, it gives strength to our tendons, ligaments and bones and provides a scaffold for the healing of skin wounds. There are approximately 20 different types of collagen in our body, each tailored to the needs of specific tissues