Integumentene

Integumentene refers to the outer covering of an animal's body. This covering serves a variety of crucial functions, including protection, sensory perception, thermoregulation, and respiration, depending on the organism.

For vertebrates, the integument is typically the skin, which is composed of multiple layers. The epidermis, the outermost layer, provides a barrier against pathogens and environmental damage. Beneath the epidermis lies the dermis, which contains blood vessels, nerves, and accessory structures like hair, feathers, scales, or glands. In some animals, the integument also includes specialized structures such as horns, antlers, or claws, which are derived from epidermal cells.

Invertebrates exhibit a wider diversity of integumentary structures. Arthropods, for instance, possess an exoskeleton made of chitin, which offers rigid support and protection but requires molting to allow for growth. Mollusks often have a shell, secreted by the mantle, that serves as a protective casing. Other invertebrates may have simple, permeable integuments that facilitate gas exchange, such as the skin of earthworms. The specific composition and complexity of the integument are directly related to the animal's habitat, lifestyle, and evolutionary history.