What are tendons made of, and what do they do?
Tendons are made out of connective tissue that has a lot of strong collagen fibers in it. This means that they are very resistant to tearing, but not very stretchy. Compared to muscles, they have fewer blood vessels in them too. Because of this, they are prone to injury when overstrained and take a lot longer to heal than other types of tissue in the body.
The bones are connected to the muscles, which cause the bones to move when the muscles tighten and relax. In some parts of the body, the muscle is directly attached to the bone. But this isn’t always possible because there often isn’t enough room on the bone, or the bone and muscle are too far apart. Tendons then act as space-saving “connectors” that transfer the movement of the muscle to the bone. One end of the tendon is attached to a muscle. The other end is firmly attached to the membrane covering the bone (the periosteum) or to the bone itself.