How does the crustacean exoskeleton provide protection and support?

The crustacean exoskeleton—also known as the integument or cuticle—serves as a protective, rigid outer covering that provides essential structural support.12

Protection and Support

• Structural Integrity: The exoskeleton is composed of a procuticle containing chitin fibers intermeshed with proteins. In many crustaceans, this structure is further hardened by the incorporation of calcium salts, such as calcite or aragonite, creating a massive, rigid shell.13
• Muscle Attachment: The exoskeleton provides a large surface area for the attachment of muscles on its interior. Together, the skeleton and muscles function as a lever system, enabling movement.4
• Mechanical Design: The cylindrical design of the exoskeleton around appendages resists bending and buckling, allowing for efficient movement with minimal skeletal material.4
• Jointed Mobility: To allow for movement, the skeleton is divided into plates and cylinders connected by thin, flexible joints that lack the rigid exocuticle.45

While the exoskeleton offers significant protection, it also limits growth, necessitating a periodic molting process where the animal sheds its old shell to accommodate a larger size.12