Collagen

• Provide mechanical strength.
• A layer of collagen prevents arteries from bursting when withstanding high pressures from blood being pumped by the heart.
• Tendons are made from collagen and connect muscles to bones, allowing them to pull on bones.
• Bones are made from collagen, and then reinforced with calcium phosphate, making them hard.
• Cartilage and connective tissue are made from collagen.