What material is responsible for the stretch needed in a ligament?

What material is responsible for the stretch needed in a ligament?

• A. Elastin
• B. Collagen
• C. Actin
• D. Myosin

Answer: (A)

Elasticity in ligaments comes from elastin, the protein that allows tissue to stretch under load and return to its original length. Ligaments also contain collagen, which provides strength and stiffness, but elastin furnishes the reversible deformation needed for stretch. This combination lets ligaments lengthen slightly during movement and snap back afterward without permanent elongation. Actin and myosin are contractile proteins in muscle, not components that give ligaments their stretch, so they don’t contribute to this property. Collagen’s primary role is tensile strength, reinforcing the tissue to resist tearing rather than enabling stretch.

Elasticity in ligaments comes from elastin, the protein that allows tissue to stretch under load and return to its original length. Ligaments also contain collagen, which provides strength and stiffness, but elastin furnishes the reversible deformation needed for stretch. This combination lets ligaments lengthen slightly during movement and snap back afterward without permanent elongation. Actin and myosin are contractile proteins in muscle, not components that give ligaments their stretch, so they don’t contribute to this property. Collagen’s primary role is tensile strength, reinforcing the tissue to resist tearing rather than enabling stretch.