Eksosyyttinen

Eksosyyttinen is a Finnish term that translates to "exoskeletal" in English. It refers to any organism or structure that possesses an external skeleton or shell for support and protection. This external covering is typically rigid and is formed from materials secreted by the body's tissues.

Many invertebrates exhibit exoskeletons. Examples include arthropods like insects, crustaceans, and arachnids, which have their exoskeletons made primarily of chitin. Mollusks, such as snails and clams, also have exoskeletons in the form of shells, which are usually composed of calcium carbonate. These external coverings provide crucial defense against predators and environmental hazards, and also serve as attachment points for muscles, facilitating movement.

Unlike the endoskeletons found in vertebrates, which grow with the organism, exoskeletons do not grow. Organisms with exoskeletons must periodically shed their old, outgrown covering and develop a new, larger one in a process called molting or ecdysis. During this vulnerable period, the organism is soft and unprotected until the new exoskeleton hardens. The term "eksosyyttinen" can also be used metaphorically to describe systems or structures that are externally supported or protected, though its primary application is biological.