Arthropod Exoskeleton: Structure and Function

Arthropod Body Covering

• The entire body of arthropods, including their appendages, is covered by a tough cuticle called the exoskeleton.
• The exoskeleton is produced by the single-layered epidermis that lies beneath it.
• The exoskeleton, also known as the "pancerz," is mainly composed of chitin, along with proteins and lipids.
• The exoskeleton in many crustaceans contains calcium salts, significantly enhancing its rigidity and durability.
• The arthropod cuticle is nearly impermeable to water and gases and provides significant protection against mechanical damage and chemical substances.
• The exoskeleton functions as an external skeleton, providing attachment points for muscles.
• The exoskeleton of each segment is made of hard plates connected by flexible membranes, which allows for movement.
• The dorsal part of the exoskeleton in crustaceans and arachnids forms a single, hard shield covering the head and thorax, which is called the carapace.
• Arthropods must shed their exoskeleton periodically through a process called molting to grow.
• During molting, the old exoskeleton splits, and the animal emerges with a new, soft exoskeleton.

Structure of Arthropod Body Covering

• Arthropod body is composed of a single-layered epidermis and a chitinous exoskeleton.
• The exoskeleton provides a protective function and serves as an attachment point for muscles.
• The epidermis (hypodermis) of arthropods produces the exoskeleton, mainly from chitin.
• The exoskeleton is several times thicker than the epidermis.
• Some insects have light-producing organs, which serve to attract prey or partners for reproduction. These organs are usually glands that produce a substance called luciferin, which emits light upon oxidation.

Other key features

• During a short period there is rapid body growth, followed by hardening of the exoskeleton.
• Molting does not affect all exoskeleton-covered parts, such as the lining of the anterior and posterior intestine, or the respiratory tract.
• Molting and growth occur throughout life in some arthropods, while others cease growing after reaching sexual maturity.
• Arthropod muscles do not form regular layers; instead, they are divided into distinct groups performing various tasks.
• Arthropod muscles, unlike those of most invertebrates, are made of striated muscle tissue.
• Most insects have wings that are formed as outgrowths of the body wall.

Explore the structure and function of the arthropod exoskeleton. The exoskeleton, primarily made of chitin, proteins, and lipids, protects against mechanical damage and serves as an external skeleton for muscle attachment. Crustaceans often have calcium salts in their exoskeletons, adding rigidity to the carapace.