A gill is an anatomical structure found in many aquatic organisms. An aquatic ecosystem is an Ecosystem located in water bodies. It is a respiration organ whose function is the extraction of oxygen from water and the excretion of carbon dioxide. Breathing / Respiration organs are used by most or all animals to exchange the gases necessary for their life functions known as respiration. Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the Water is a common Chemical substance that is essential for the survival of all known forms of Life. Carbon dioxide ( Chemical formula:) is a Chemical compound composed of two Oxygen Atoms covalently bonded to a single The microscopic structure of a gill is such that it presents a very large surface area to the external environment. Surface area is the measure of how much exposed Area an object has

Many microscopic aquatic animals, and those which are somewhat larger but inactive, are able to absorb adequate oxygen through the entire surface of their bodies, and thus they often can respire quite adequately without a gill. However, more complex or more active aquatic organisms usually require a gill or gills.

Gills usually consist of thin plates of tissue, branches, or slender tufted processes. In Anatomy, a process ( Latin: processus) is a projection or outgrowth of tissue from a larger body With the exception of some aquatic insects, they contain blood or coelomic fluid, from which gases are exchanged through the thin walls. Insects ( Class Insecta) are a major group of Arthropods and the most diverse group of Animals on the Earth with over a million described Blood is a specialized Bodily fluid that delivers necessary substances to the body's cells ��such as nutrients and oxygen—and transports Waste products By the broadest definition a body cavity is any fluid filled space in a Multicellular organism. Oxygen is carried by the blood to other parts of the body. Carbon dioxide passes from the blood through the thin gill tissue into the water.

Gills or gill-like organs, located in different parts of the body, are found in various groups of aquatic animals, including mollusks, crustaceans, insects, fish, and amphibians. Molluscs are animals belonging to the phylum Mollusca. There are around 250000 extant Species within the phylum with an estimated 70000 Structure of crustaceans As Arthropods crustaceans have a stiff Exoskeleton, which must be shed to allow the animal to grow ( Ecdysis or molting Insects ( Class Insecta) are a major group of Arthropods and the most diverse group of Animals on the Earth with over a million described Fish are aquatic Vertebrate animals that are typically ectothermic (previously Cold-blooded) covered with scales, and equipped with two Prehistoric amphibian Amphibians (class Amphibia such as Frogs Toads Salamanders Newts Gymnophiona, Sirens and

Invertebrate gills

Respiration in the Echinodermata (includes starfish and sea urchins) is carried out using a very primitive version of gills called papulli. Echinoderms (Phylum Echinodermata) are a phylum of marine Animals (including Sea stars) Starfish (also called sea stars) are any Echinoderms belonging to the class Asteroidea. Sea urchins are small globular spiny sea cat animals composing most of class Echinoidea. These are thin protuberances on the surface of the body containing diverticula of the water vascular system. This is an article about the rock music band "Circulatory System"

In crustaceans, mollusks and some insects, gills are tufted or plate-like structures at the surface of the body in which blood circulates. Structure of crustaceans As Arthropods crustaceans have a stiff Exoskeleton, which must be shed to allow the animal to grow ( Ecdysis or molting Molluscs are animals belonging to the phylum Mollusca. There are around 250000 extant Species within the phylum with an estimated 70000

The gills of other insects are of the tracheal kind, and also include both thin plates and tufted structures, and, in the larval dragon fly, the wall of the caudal end of the alimentary tract (rectum) is richly supplied with tracheae as a rectal gill. A larva ( Latin; plural larvae) is a juvenile form of Animal with indirect development, undergoing Metamorphosis (for example Anisoptera redirects here For the genus of trees see Anisoptera (tree. The rectum (from the Latin rectum intestinum, meaning straight intestine) is the final straight portion of the Large intestine in some Mammals Water pumped into and out of the rectum provide oxygen to the closed tracheae. In the aquatic insects, a unique type of respiratory organ is used, the tracheal gill, which contains air tubes. Many terrestrial Arthropods have evolved a closed Respiratory system composed of Spiracles, tracheae and Tracheoles to transport metabolic The oxygen in these tubes is renewed through the gills.

Physical gills

Physical gills are a type of structural adaptation common among some types of aquatic insects, in which atmospheric oxygen is held within an area into which the spiracles open. Insects ( Class Insecta) are a major group of Arthropods and the most diverse group of Animals on the Earth with over a million described Spiracles are small openings on the surface of some Animals that usually lead to Respiratory systems In Elasmobranchs ( Sharks and The structure (often called a plastron) typically consists of dense patches of hydrophobic setae on the body, which prevent water entry into the spiracles. The plastron is the nearly flat part of the shell structure of a Turtle or Tortoise, what one would call the belly similar in composition to the Carapace In Chemistry, hydrophobicity (from the combining form of water in Attic Greek hydro- and for fear phobos) refers to the physical property of Seta (plural setae) is a biological term derived from the Latin word for " Bristle " The physical properties of the interface between the trapped air bubble and the surrounding water function so as to accomplish gas exchange through the spriacles, almost as if the insect were in atmospheric air. Carbon dioxide diffuses out into the surrounding water due to its high solubility, while oxygen diffuses into bubbles as the concentration within the bubble has been reduced by respiration, and nitrogen also diffuses out as its tension has been increased. Carbon dioxide ( Chemical formula:) is a Chemical compound composed of two Oxygen Atoms covalently bonded to a single Solubility is the characteristic Physical property referring to the ability of a given substance the Solute, to dissolve in a Solvent. Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the In Animal physiology, respiration is the transport of Oxygen from the outside air to the cells within tissues and the transport of Carbon dioxide Oxygen diffuses into the bubble at a higher rate than Nitrogen diffuses out. However, water surrounding the insect can become oxygen-depleted if there is no water movement, so many aquatic insects in still water actively direct a flow of water over their bodies.

The physical gill mechanism allows aquatic insects with plastrons to remain constantly submerged. Examples include many beetles in the family Elmidae, aquatic weevils, and true bugs in the family Aphelocheiridae. Beetles are the group of Insects with the largest number of known Species. A weevil is any Beetle from the Curculionoidea Superfamily. They are usually small less than 6  mm (¼  Inch) and herbivorous Hemiptera is an order of Insects comprising around 80000 Species of Cicadas Aphids Planthoppers Leafhoppers

Vertebrate gills

The red gills inside a detached tuna head (viewed from behind)

Gills of vertebrates are developed in the walls of the pharynx along a series of gill slits opening to the exterior. Tuna, are several Species of ocean-dwelling Fish in the family Scombridae, mostly in the genus Thunnus. Vertebrates are members of the Subphylum Vertebrata, Chordates with backbones or spinal columns The grouping sometimes includes The pharynx (plural pharynges) is the part of the Neck and Throat situated immediately Posterior to (behind the Mouth and Nasal In fish, the gills are located on both sides of the pharynx. Gills are madel of filaments which help increase surface area for oxygen exchange. In bony fish, the gills are covered by a bony cover called an operculum. The operculum of a bony fish is the hard bony flap covering and protecting the Gills In most fish the rear edge of the operculum roughly marks the division between When a fish breathes, it opens its mouth at regular times and draws in a mouthful of water. It then draws the sides of its throat together, forcing the water through the gill openings. The water passes over the gills on the outside. Valves inside the mouth keep the water from escaping through the mouth again. The operculum can be very important in adjusting the pressure of water inside of the pharynx to allow proper ventilation of the gills. The pharynx (plural pharynges) is the part of the Neck and Throat situated immediately Posterior to (behind the Mouth and Nasal Lampreys and sharks lack an operculum, they have multiple gill openings. Also, they must use different methods to force water over the gills. In sharks and rays, this ventilation of the gills is achieved either by the use of spiracles or ram ventilation (ventilation by constantly swimming). Spiracles are small openings on the surface of some Animals that usually lead to Respiratory systems In Elasmobranchs ( Sharks and

In most species, a countercurrent exchange system is employed to enhance the diffusion of substances in and out of the gill, with blood and water flowing in opposite directions to each other. Countercurrent exchange is a mechanism used to transfer some property of a Fluid from one flowing current of fluid to another across a Semipermeable membrane or thermally-conductive Water taken into the mouth passes out of the slits, bathing the gills as it passes.

Some fish utilize the gills for the excretion of electrolytes. Fish are aquatic Vertebrate animals that are typically ectothermic (previously Cold-blooded) covered with scales, and equipped with two An electrolyte is any substance containing free Ions that behaves as an electrically conductive medium Gills' large surface area tends to create a problem for fish seeking to regulate the osmolarity of their internal fluids. Osmolarity is a measure of the osmoles of solute per Liter of solution while the osmolality is a measure of the osmoles of Solute per Kilogram Saltwater is less dilute than these internal fluids; as a consequence, saltwater fish lose large quantities of water osmotically through their gills. To regain the water, they drink large amounts of seawater and excrete the salt. Seawater is Water from a Sea or Ocean. On average seawater in the world's oceans has a Salinity of about 3 Salt is a Dietary mineral composed primarily of Sodium chloride that is essential for Animal life but toxic to most land plants Freshwater is more dilute than the internal fluids of fish, however, so freshwater fish gain water osmotically through their gills.

The gill slits of fish are believed to be the evolutionary ancestors of the tonsils, thymus gland, and Eustachian tubes, as well as many other structures derived from the embryonic branchial pouches. For the structure in the Cerebellum, see Cerebellar tonsil. The tonsils are areas In Human anatomy, the thymus is an organ located in the upper Anterior portion of the chest cavity just behind the Sternum. The Eustachian tube (or auditory tube) is a tube that links the Pharynx to the Middle ear. In the development of vertebrate animals, Pharyngeal or branchial pouches form on the endodermal side between the Branchial arches and pharyngeal In some amphibians, the gills occupy the same position on the body but protrude as external tufts. Prehistoric amphibian Amphibians (class Amphibia such as Frogs Toads Salamanders Newts Gymnophiona, Sirens and

An Alpine newt larva showing the gills, which flare just behind the head

Branchia

Branchia (pl. The Alpine Newt ( Triturus alpestris) belongs to the order Salamander (Urodela or Caudata in the class of Amphibians. branchiæ) is the name given by the Ancient Greek naturalists to the gills of fish. The Ancient Greek language is the historical stage in the development of the Hellenic language family spanning the Archaic (c Fish are aquatic Vertebrate animals that are typically ectothermic (previously Cold-blooded) covered with scales, and equipped with two Galen observed that they are full of little foramina, big enough to admit gases, but too fine to give passage to water. Galen ( Greek: Γαληνός Galēnos; Latin: Claudius Galenus, Aelius Galenus, Claudius Aelius Galenus, or Pliny the Elder held that fish respired by their gills, but observed that Aristotle was of another opinion. Gaius or Caius Plinius Secundus, ( AD 23 – August 25, AD 79 better known as Pliny the Elder, was an ancient Author Aristotle (Greek Aristotélēs) (384 BC – 322 BC was a Greek philosopher a student of Plato and teacher of Alexander the Great. ^[1]

The word branchia comes from the Greek βράγχια, "gills", plural of βράγχιον (in singular, meaning a fin). Greek (el ελληνική γλώσσα or simply el ελληνικά — "Hellenic" is an Indo-European language, spoken today by 15-22 million people mainly fin is a surface used to produce lift and Thrust or to steer while traveling in Water, air or other Fluid media ^[2]

References

1. ^ This article incorporates content from the 1728 Cyclopaedia, a publication in the public domain. Cyclopaedia or A Universal Dictionary of Arts and Sciences ( folio, 2 vols The public domain is a range of abstract materials &ndash commonly referred to as Intellectual property &ndash which are not owned or controlled by anyone
2. ^ "Branchia". Oxford English Dictionary. Oxford University Press. 2nd Ed. 1989.

See also

• Aquatic respiration
• Book lung
• Lung
• Artificial gills (human)