An exoskeleton is an external anatomical feature that supports and protects an animal's body, in contrast to the internal endoskeleton of, for example, a human. Whilst many many other invertebrate animals (such as shelled mollusks) have exoskeletons in the sense of external hard parts, the character is most associated with the arthropods (i.e. insects, spiders, myriapods and crustaceans). Exoskeletons contain rigid and resistant components that fulfil a set of functional roles including protection, excretion, sensing, support, feeding and (for terrestrial organisms) acting as a barrier against dessiccation. Exoskeletons first appeared in the fossil record about 550 million years ago, and their evolution has been seen as critical as a driving role in the Cambrian explosion of animals that took place subsequent to this time. Human heart and lungs, from an older edition of Grays Anatomy. ... For other uses, see Animal (disambiguation). ... Endoskeleton of a swordfish An endoskeleton is an internal support structure of an animal. ... Invertebrate is a term that describes any animal without a spinal column. ... Classes Caudofoveata Aplacophora Polyplacophora - Chitons Monoplacophora Bivalvia - Bivalves Scaphopoda - Tusk shells Gastropoda - Snails and Slugs Cephalopoda - Squids, Octopuses, etc. ... Subphyla and Classes Subphylum Trilobitomorpha Trilobita - trilobites (extinct) Subphylum Chelicerata Arachnida - spiders,scorpions, etc. ... Orders Subclass Apterygota Archaeognatha (bristletails) Thysanura (silverfish) Monura - extinct Subclass Pterygota Infraclass Paleoptera (may be paraphyletic) Ephemeroptera (mayflies) Palaeodictyoptera - extinct Megasecoptera - extinct Archodonata - extinct Diaphanopterodea - extinct Protodonata - extinct Odonata (dragonflies and damselflies) Infraclass Neoptera Superorder Exopterygota Caloneurodea - extinct Titanoptera - extinct Protorthoptera - extinct Grylloblattodea (ice-crawlers) Mantophasmatodea (gladiators) Plecoptera (stoneflies) Embioptera... Diversity 111 families, 40,000 species Suborders Mesothelae Mygalomorphae Araneomorphae  See table of families Wikispecies has information related to: Spiders Spiders are predatory invertebrate animals that have two body segments, eight legs, no chewing mouth parts and no wings. ... Classes [1] Chilopoda Diplopoda Pauropoda Symphyla Myriapoda is a subphylum of arthropods containing millipedes, centipedes and others. ... Classes & Subclasses Branchiopoda Phyllopoda Sarsostraca Remipedia Cephalocarida Maxillopoda Thecostraca Tantulocarida Branchiura Pentastomida Mystacocarida Copepoda Ostracoda Myodocopa Podocopa Malacostraca Phyllocarida Hoplocarida Eumalacostraca The nauplius larva of a dendrobranchiate Porcellio scaber, the common rough woodlouse, a terrestrial crustacean Pollicipes polymerus, the gooseneck barnacle Glyphea pseudastacus, a fossil glypheoid The crustaceans (Crustacea) are... The Cambrian explosion is the geologically kukko sudden appearance in the fossil record of the ancestors of familiar animals, starting about 542 million years ago (Mya). ...

Arthropod exoskeletons

emily was ere 07

Microscopic structure

A typical arthropod exoskeleton is a multi-layered structure with four functional regions: epicuticle, procuticle, epidermis and basement membrane.^[1]. Of these, the epicuticle is a multi-layered external barrier that, especially in terrestrial arthropods, acts as a barrier against dessiccation. The strength of the exoskeleton is provided by the underlying procuticle, which is in turn secreted by the epidermis. Arthropod cuticle is a biological composite material, consisting of two main portions: fibrous chains of alpha-chitin within a matrix of silk-like and globular proteins, of which the most well-known is the rubbery protein called resilin. The relative abundance of these two main components varies from approximately 50/50 to 70/30 protein/chitin, with softer parts of the exoskeleton having a higher proportion of chitin. Although the cuticle is relatively soft when first secreted, it soon hardens in a poorly-understood process that involves dehydration and/or tanning mediated by hydrophobic chemicals called phenolics. Different types of interaction between the proteins and chitin leads to varying mechanical properties of the exoskeleton.
In addition to the chitino-proteinaceous composite of the cuticle, many crustaceans, some myriapods and the extinct trilobites further impregnate the cuticle with mineral salts, above all calcium carbonate, which can make up up to 40% of the cuticle. This can lead to great mechanical strength.
The epicuticle is the outermost portion of the exoskeleton of an insect (and various other arthropods); its exact composition and structure may differ somewhat among different taxa, but certain aspects can be generalized: It is secreted by the epidermis, and is deposited on top of the procuticle via pores that... The procuticle is the major portion of the exoskeleton of an insect (and various other arthropods); its exact composition and structure may differ somewhat among different taxa, but certain aspects can be generalized: When first secreted by the epidermis, it is soft, pliable, and pale, as much of the chemical... Look up Epidermis in Wiktionary, the free dictionary. ... ... The epicuticle is the outermost portion of the exoskeleton of an insect (and various other arthropods); its exact composition and structure may differ somewhat among different taxa, but certain aspects can be generalized: It is secreted by the epidermis, and is deposited on top of the procuticle via pores that... The procuticle is the major portion of the exoskeleton of an insect (and various other arthropods); its exact composition and structure may differ somewhat among different taxa, but certain aspects can be generalized: When first secreted by the epidermis, it is soft, pliable, and pale, as much of the chemical... Look up Epidermis in Wiktionary, the free dictionary. ... A cloth of woven carbon fiber filaments, a common element in composite materials Composite materials (or composites for short) are engineered materials made from two or more constituent materials with significantly different physical or chemical properties and which remain separate and distinct within the finished structure. ... Structure of the chitin molecule, showing two of the N-Acetylglucosamine units that repeat to form long chains in beta-1,4 linkage. ... Yep References and External Links Harnessing flea power to create near-perfect rubber, Media Release from the CSIRO Article published in Nature Shorter news item from Nature Summary from University of South Australia Insect Rubber article from Future Materials Categories: Biochemistry stubs | Proteins | Biochemistry ... Dehydration (hypohydration) is the removal of water (hydro in ancient Greek) from an object. ... Tanned leather in Marrakech This article or section does not cite any references or sources. ... In chemistry, hydrophobic or lipophilic species, or hydrophobes, tend to be electrically neutral and nonpolar, and thus prefer other neutral and nonpolar solvents or molecular environments. ... In organic chemistry, phenols, sometimes called phenolics, are a class of chemical compounds consisting of a hydroxyl group (-OH) attached to an aromatic hydrocarbon group. ... Classes Remipedia Cephalocarida Branchiopoda Ostracoda Maxillopoda Malacostraca The crustaceans (Crustacea) are a large group of arthropods (55,000 species), usually treated as a subphylum. ... Classes Chilopoda - Centipedes Diplopoda - Millipedes Pauropoda - Pauropods Symphyla - Symphylans Four groups of arthropods—the centipedes, millipedes, pauropods, and symphylans—share a number of common features such as a similar body plan consisting of a head followed by an elongate trunk with many legs. ... Orders Agnostida Redlichiida Corynexochida Lichida Nektaspida? Phacopida Proetida Asaphida Harpetida Ptychopariida Trilobites are extinct arthropods in the class Trilobita. ...

Organisation

The head of an ant: Chitin Type

The arthropod exoskeleton is typically divided into different functional units to allow flexibility in an often otherwise rigid structure. For example, the head is a fused capsule; and the trunk is often divided into a series of articulating sclerites called tergites. In addition, the characteristic limbs of arthropods need to be jointed. The internal surface of the exoskeleton is often elaborated into a set of specialised structures called apodemes that allow the attachment of muscles. Such endoskeletal components of the arthropod skeleton can be highly complex, as in crabs and lobsters.
A photo of an ant head taken with a Scanning Electron Microscope [1] File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... A photo of an ant head taken with a Scanning Electron Microscope [1] File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Subfamilies Aenictogitoninae Agroecomyrmecinae Amblyoponinae (incl. ... A tergum (pl. ...

Ecdysis

• See also main article: Ecdysis

A spider undergoes moulting

The relative rigidity of the exoskeleton means that continuous growth of arthropods is not possible. Therefore, growth is periodic and concentrated into a period of time when the exoskeleton is shed, called moulting or ecdysis, which is under the control of a hormone called ecdysone. Moulting is a complex process that is invariably dangerous for the arthropod involved. Before the old exoskeleton is shed, the cuticle separates from the epidermis through a process called apolysis. New cuticle is excreted by the underlying epidermis, and mineral salts are usually withdrawn from the old cuticle for re-use. After the old cuticle is shed, the arthropod typically pumps up its body (for example, by air or water intake) to allow the new cuticle to expand to a larger size: the process of hardening by dehydration of the cuticle then takes place. Newly molted arthropods typically appear pale or white, and darken as the cuticle hardens.
Ecdysis is the molting of the cuticula in arthropods and related groups (Ecdysozoa). ... Image File history File linksMetadata Exoskeleton3. ... Image File history File linksMetadata Exoskeleton3. ... Diversity 111 families, 40,000 species Suborders Mesothelae Mygalomorphae Araneomorphae  See table of families Wikispecies has information related to: Spiders Spiders are predatory invertebrate animals that have two body segments, eight legs, no chewing mouth parts and no wings. ... In birds, moulting or molting is the routine shedding of old feathers. ... Ecdysis is the molting of the cuticula in arthropods and related groups (Ecdysozoa). ... Ecdysone is a prohormone of the major insect moulting hormone 20-hydroxyecdysone, which is secreted from the prothoracic glands. ...

Natural exoskeletons

Excellent as defensive adaptation, exoskeletons may nevertheless cause problems where entities carry an excessive weight to surface-area ratio or whenever organism growth requires an enlargement of the exoskeleton. Exoskeletons are found on many different types of organisms including shellfish and insects. A biological adaptation is an anatomical structure, physiological process or behavioral trait of an organism that has evolved over a period of time by the process of natural selection such that it increases the expected long-term reproductive success of the organism. ...

Types

• Bone and cartilage
  • Ostracoderms (extinct armoured fish)
  • Turtles, Terrapins and Tortoises
• Chitin
  • Arthropods
  • some Bacteria
• Calcium compounds
  • Corals
  • Echinoderms
  • Mollusks
  • some Polychaetes
• Silicate
  • Diatoms
  • Radiolaria

Grays Anatomy illustration of a human femur. ... Cartilage is a type of dense connective tissue. ... Diversity ca. ... Look up terrapin in Wiktionary, the free dictionary. ... This article or section is in need of attention from an expert on the subject. ... Structure of the chitin molecule, showing two of the N-Acetylglucosamine units that repeat to form long chains in beta-1,4 linkage. ... Subphyla and Classes Subphylum Trilobitomorpha Trilobita - trilobites (extinct) Subphylum Chelicerata Arachnida - spiders,scorpions, etc. ... Phyla Actinobacteria Aquificae Chlamydiae Bacteroidetes/Chlorobi Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Lentisphaerae Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Verrucomicrobia Bacteria (singular: bacterium) are unicellular microorganisms. ... General Name, Symbol, Number calcium, Ca, 20 Chemical series alkaline earth metals Group, Period, Block 2, 4, s Appearance silvery white Standard atomic weight 40. ... Extant Subclasses and Orders Alcyonaria    Alcyonacea    Helioporacea Zoantharia    Antipatharia    Corallimorpharia    Scleractinia    Zoanthidea [1][2]  See Anthozoa for details For other uses, see Coral (disambiguation). ... Classes Subphylum Homalozoa Gill & Caster, 1960 Class Homostelea Class Homoiostelea Class Stylophora Gill & Caster, 1960 Class Ctenocystoidea Robison & Sprinkle, 1969 Subphylum Crinozoa Class Eocrinoidea Jaekel, 1899 Class Paracrinoidea Regnéll, 1945 Class Cystoidea von Buch, 1846 Class Blastoidea Class Crinoidea Subphylum Asterozoa Class Ophiuroidea Class Asteroidea Subphylum Echinozoa Helicoplacoidea †  ?Arkarua... Classes Caudofoveata Aplacophora Polyplacophora Monoplacophora Bivalvia Scaphopoda Gastropoda Cephalopoda † Rostroconchia The mollusks or molluscs are the large and diverse phylum Mollusca, which includes a variety of familiar creatures well-known for their decorative shells or as seafood. ... Subclasses Palpata Scoleoida Tomopteris from plankton The Polychaeta or polychaetes are a class of annelid worms, generally marine. ... In chemistry, a silicate is a compound containing an anion in which one or more central silicon atoms are surrounded by electronegative ligands. ... Orders Centrales Pennales Diatoms (Greek: (dia) = through + (temnein) = to cut, i. ... Possible classes Polycystinea Acantharea Taxopodea Radiolaria are amoeboid protozoa that produce intricate mineral skeletons, typically with a central capsule dividing the cell into inner and outer portions, called endoplasm and ectoplasm. ...

Artificial human exoskeletons

Humans have long used armour as an artificial exoskeleton for protection, especially in combat. Exoskeletal machines are also starting to be used for medical and industrial purposes, while Powered human exoskeletons are a feature of science fiction writing, but are currently moving into prototype stage. Orthoses are a limited, medical form of exoskeleton. Trinomial name Homo sapiens sapiens Linnaeus, 1758 Humans, or human beings, are bipedal primates belonging to the mammalian species Homo sapiens (Latin: wise man or knowing man) in the family Hominidae (the great apes). ... Armour sucks ass alottttttttttt Armour was also commonly used to protect war animals, such as war horses and elephants. ... U.S. Army conceptual mockup of an exoskeleton-equipped soldier. ... An orthosis is a device that is applied to a part of the body to correct deformity, improve function, or relieve symptoms of a disease. ...

In history

Medieval armour (in the case of mounted knights) is not load-bearing, but furnishes the appearance of an artificial human exoskeleton. Armour sucks ass alottttttttttt Armour was also commonly used to protect war animals, such as war horses and elephants. ...

In medicine

An orthosis (plural orthoses) is a device which attaches to a limb, or the torso, to support the function or correct the shape of that limb or the spine. Orthotics is the field dealing with orthoses, their use, and their manufacture. An orthotist is a person who designs and fits orthoses. An orthosis is a device that is applied to a part of the body to correct deformity, improve function, or relieve symptoms of a disease. ... Orthotics is the field concerned with the application and manufacture of orthoses, devices which support or correct human function . ... As defined by the American Board for Certification in Orthotics and Prosthetics, Inc. ...

A limb prosthesis (plural prostheses) is a device that substitutes for a missing part of a limb. If the prosthesis is a hollow shell and self-carrying, it is exoskeletal. If internal tubes are used in the device and the cover (cosmesis) to create the outside shape is made of a soft, non-carrying material, it is endoskeletal. Prosthetics is the field that deals with prostheses, use, and their manufacture. A prosthetist is a person who designs and fits prostheses. A United States Army soldier plays table football with two prosthetic arms Jon Comer, professional skateboarder with a prosthetic leg. ... It has been suggested that this article or section be merged into Plastic Surgery. ... A United States soldier demonstrates Foosball with two prosthetic limbs In medicine, a prosthesis is an artificial extension that replaces a missing part of the body. ... A United States Army soldier plays foosball with two prosthetic arms Jon Comer, professional skateboarder with a prosthetic leg. ...

In modern and near-future technology

Main article: Powered exoskeleton

U.S. Army conceptual mockup of an exoskeleton-equipped soldier. ...

References

See also

• Mechatronics
• Spiracle - Small openings in the exoskeleton that allow insects to breathe

Mechatronics is the synergistic combination of mechanical engineering (mecha for mechanisms, i. ... Spiracles are small openings on the surface of animals that usually lead to respiratory systems. ...

External links

Biology

• Geometry and Pattern in Nature 3: The holes in radiolarian and diatom tests

Modern technology

• Bionic Boots
• PowerSkip
• Berkeley Lower Extremity Exoskeleton (BLEEX)
• University of Washington Exo Arm Project