Citizendia
Your Ad Here

For the village in Tibet, see Lung, Tibet. Lung is a Village in the Tibet Autonomous Region of China.
The lungs flank the heart and great vessels in the chest cavity.
The lungs flank the heart and great vessels in the chest cavity. [1]
Air enters and leaves the lungs via a conduit of cartilaginous passageways — the bronchi and bronchioles. In this image, lung tissue has been dissected away to reveal the bronchioles
Air enters and leaves the lungs via a conduit of cartilaginous passageways — the bronchi and bronchioles. In this image, lung tissue has been dissected away to reveal the bronchioles[1]

The lung is the essential respiration organ in air-breathing animals, including most tetrapods, a few fish and a few snails. Breathing / Respiration organs are used by most or all animals to exchange the gases necessary for their life functions known as respiration. Tetrapods ( Greek τετραποδη tetrapoda, Latin Quadruped, "four-footed" are Vertebrate Animals Fish are aquatic Vertebrate animals that are typically ectothermic (previously Cold-blooded) covered with scales, and equipped with two The word snail is a Common name that can be used for almost all members of the Molluscan class Gastropoda which have coiled shells in the The most primitive animals with a lung are the lungfish (vertebrate) and the pulmonate snails (invertebrate). Lungfish are freshwater fish belonging to the Subclass Dipnoi. Vertebrates are members of the Subphylum Vertebrata, Chordates with backbones or spinal columns The grouping sometimes includes The Pulmonata or "pulmonates" are an order (once a Subclass) of Snails and Slugs that have developed a pallial Lung An invertebrate is an Animal lacking a Vertebral column. The group includes 98% of all animal Species — all animals except those in the Chordate In mammals and the more complex life forms, the two lungs are located in the chest on either side of the heart. The heart is a muscular organ in all Vertebrates responsible for pumping Blood through the Blood vessels by repeated rhythmic Their principal function is to transport oxygen from the atmosphere into the bloodstream, and to release carbon dioxide from the bloodstream into the atmosphere. Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the Temperature and layers The temperature of the Earth's atmosphere varies with altitude the mathematical relationship between temperature and altitude varies among five This is an article about the rock music band "Circulatory System" Carbon dioxide ( Chemical formula:) is a Chemical compound composed of two Oxygen Atoms covalently bonded to a single This exchange of gases is accomplished in the mosaic of specialized cells that form millions of tiny, exceptionally thin-walled air sacs called alveoli. The cell is the structural and functional unit of all known living Organisms It is the smallest unit of an organism that is classified as living and is often called An alveolus (plural alveoli, from Latin alveolus, "little cavity" is an anatomical structure that has the form of a hollow cavity

Medical terms related to the lung often begin with pulmo-, from the Latin pulmonarius ("of the lungs"), or with pneumo- (from Greek πνεύμω "breath")

Contents

Respiratory function

The lungs are very important. Latin ( lingua Latīna, laˈtiːna is an Italic language, historically spoken in Latium and Ancient Rome. The Ancient Greek language is the historical stage in the development of the Hellenic language family spanning the Archaic (c Energy production to aerobic respiration requires oxygen and glucose and produces carbon dioxide as a gaseous waste product, creating a need for an efficient means of oxygen delivery to cells and excretion of carbon dioxide from cells. Cellular respiration is the set of the metabolic reactions and processes that take place in Organisms cells to convert biochemical energy from In small organisms, such as single-celled bacteria, this process of gas exchange can take place entirely by simple diffusion. Diffusion is the net movement of particles (typically molecules from an area of high concentration to an area of low concentration by uncoordinated random movement In larger organisms, this is not possible; only a small proportion of cells are close enough to the surface for oxygen from the atmosphere to enter them through diffusion. Two major adaptations made it possible for organisms to attain great multicellularity: an efficient circulatory system that conveyed gases to and from the deepest tissues in the body, and a large, internalized respiratory system that centralized the task of obtaining oxygen from the atmosphere and bringing it into the body, whence it could rapidly be distributed to all the circulatory system. An adaptation is a characteristic of an Organism that has been favored by Natural selection and Multicellular organisms are Organisms consisting of more than one cell, and having Differentiated cells that perform specialized functions This is an article about the rock music band "Circulatory System" This page is about the physical properties of gas as a state of matter In living organisms a respiratory system functions to allow Gas exchange. The lungs also protect the heart from damage to a certain degree.

In air-breathing vertebrates, respiration occurs in a series of steps. Air is brought into the animal via the airways — in reptiles, birds and mammals this often consists of the nose; the pharynx; the larynx; the trachea (also called the windpipe); the bronchi and bronchioles; and the terminal branches of the respiratory tree. Anatomically a nose is a protuberance in Vertebrates that houses the Nostrils or nares which admit and expel air for respiration in conjunction with the The pharynx (plural pharynges) is the part of the Neck and Throat situated immediately Posterior to (behind the Mouth and Nasal The larynx (plural larynges) colloquially known as the voicebox, is an organ in the Neck of Mammals involved in protection of the The traceartes, or windpipe, is a tube that has an inner diameter of about 20-25 mm and a length of about 10-16 cm in humans A bronchus (plural bronchi, adjective bronchial) is a caliber of airway in the Respiratory tract that conducts air into the Lungs No Gas The bronchioles or bronchioli are the first Airway branches that no longer contain Cartilage. The respiratory tree describes the branching structure of the Vertebrate Lung. The lungs of mammals are a rich lattice of alveoli, which provide an enormous surface area for gas exchange. A network of fine capillaries allows transport of blood over the surface of alveoli. Capillaries are the smallest of a body's Blood vessels measuring 5-10 μm in diameter which connect Arterioles and Venules and enable the interchange Blood is a specialized Bodily fluid that delivers necessary substances to the body's cells such as nutrients and oxygen—and transports Waste products Oxygen from the air inside the alveoli diffuses into the bloodstream, and carbon dioxide diffuses from the blood to the alveoli, both across thin alveolar membranes. MembraneA biological membrane or biomembrane is an enclosing or separating Amphipathic layer that acts as a barrier within or around a cell.

The drawing and expulsion of air is driven by muscular action; in early tetrapods, air was driven into the lungs by the pharyngeal muscles, whereas in reptiles, birds and mammals a more complicated musculoskeletal system is used. Muscle (from Latin musculus, diminutive of mus "mouse" is contractile tissue of the body and is derived from the Tetrapods ( Greek τετραποδη tetrapoda, Latin Quadruped, "four-footed" are Vertebrate Animals The pharynx (plural pharynges) is the part of the Neck and Throat situated immediately Posterior to (behind the Mouth and Nasal Reptiles, or members of the class Reptilia are air-breathing Cold-blooded Vertebrates that have skin covered in scales as opposed to hair or feathers Birds ( class Aves) are bipedal endothermic ( Warm-blooded) Vertebrate animals that lay eggs. Mammals ( class Mammalia) are a class of Vertebrate Animals characterized by the presence of Sweat glands, including sweat glands The musculoskeletal system (also known as the locomotor system is an organ system that gives Animals the ability to physically move using the Muscles and In the mammal, a large muscle, the diaphragm (in addition to the internal intercostal muscles) drives ventilation by periodically altering the intra-thoracic volume and pressure; by increasing volume and thus decreasing pressure, air flows into the airways down a pressure gradient, and by reducing volume and increasing pressure, the reverse occurs. For other types of diaphragm see Diaphragm. In the Anatomy of Mammals the thoracic diaphragm is a sheet of Muscle The volume of any solid plasma vacuum or theoretical object is how much three- Dimensional space it occupies often quantified numerically Pressure (symbol 'p' is the force per unit Area applied to an object in a direction perpendicular to the surface During normal breathing, expiration is passive and no muscles are contracted (the diaphragm relaxes). Breathing takes Oxygen in and Carbon dioxide out of the body Aerobic Organisms require oxygen to create energy via respiration, in

Another name for this inspiration and expulsion of air is ventilation. In Respiratory physiology, ventilation (or ventilation rate) is the rate at which gas enters or leaves the Lung. Vital capacity is the maximum volume of air that a person can exhale after maximum inhalation. A person's vital capacity can be measured by a spirometer (spirometry). A spirometer is an apparatus for measuring the Volume of Air inspired and expired by the Lungs It is a precision differential Pressure Transducer Spirometry (meaning the measuring of breath) is the most common of the Pulmonary Function Tests (PFTs measuring Lung function specifically the measurement In combination with other physiological measurements, the vital capacity can help make a diagnosis of underlying lung disease.

Non respiratory functions

In addition, the lungs also:

Mammalian lungs

Further information: Human lung

The lungs of mammals have a spongy texture and are honeycombed with epithelium having a much larger surface area in total than the outer surface area of the lung itself. The human lungs are the human organs of respiration. Humans have two Lungs with the left being divided into two lobes and the right into three lobes In biology and medicine epithelium is a tissue composed of cells that line the cavities and surfaces of structures throughout the body The lungs of humans are typical of this type of lung. The human lungs are the human organs of respiration. Humans have two Lungs with the left being divided into two lobes and the right into three lobes

Breathing is largely driven by the muscular diaphragm at the bottom of the thorax. For other types of diaphragm see Diaphragm. In the Anatomy of Mammals the thoracic diaphragm is a sheet of Muscle Contraction of the diaphragm pulls the bottom of the cavity in which the lung is enclosed downward. Air enters through the oral and nasal cavities; it flows through the larynx and into the trachea, which branches out into the main bronchi and then subsequent divisions. During exercise, the diaphragm contracts, forcing the air out more quickly and forcefully. A muscles contraction (also known as a muscle twitch or simply twitch) occurs when a Muscle fibre generates tension through the action of Actin The rib cage itself is also able to expand and contract to some degree, through the action of other respiratory and accessory respiratory muscles. The human rib cage, also known as the thoracic cage, is a bony and cartilaginous structure which surrounds the thoracic (chest cavity and supports the pectoral As a result, air is sucked into or expelled out of the lungs, always moving down its pressure gradient. This type of lung is known as a bellows lung as it resembles a blacksmith's bellows. A bellows is a device for delivering pressurized Air in a controlled quantity to a controlled location [3]


Anatomy

In humans, the trachea divides into the two main bronchi that enter the roots of the lungs. The bronchi continue to divide within the lung, and after multiple divisions, give rise to bronchioles. The bronchial tree continues branching until it reaches the level of terminal bronchioles, which lead to alveolar sacs. Alveolar sacs are made up of clusters of alveoli, like individual grapes within a bunch. An alveolus (plural alveoli, from Latin alveolus, "little cavity" is an anatomical structure that has the form of a hollow cavity The individual alveoli are tightly wrapped in blood vessels, and it is here that gas exchange actually occurs. Deoxygenated blood from the heart is pumped through the pulmonary artery to the lungs, where oxygen diffuses into blood and is exchanged for carbon dioxide in the hemoglobin of the erythrocytes. The heart is a muscular organ in all Vertebrates responsible for pumping Blood through the Blood vessels by repeated rhythmic The pulmonary arteries carry Blood from the Heart to the Lungs. Diffusion is the net movement of particles (typically molecules from an area of high concentration to an area of low concentration by uncoordinated random movement Hemoglobin ( also spelled haemoglobin and abbreviated Hb or Hgb) is the Iron -containing Oxygen -transport Metalloprotein Red blood cells are the most common type of Blood cell and the Vertebrate body's principal means of delivering Oxygen to the body tissues via the Blood The oxygen-rich blood returns to the heart via the pulmonary veins to be pumped back into systemic circulation.

1:Trachea 2:Pulmonary artery 3:Pulmonary vein 4:Alveolar duct 5:Alveoli 6:Cardiac notch 7:Bronchioles 8:Tertiary bronchi 9:Secondary bronchi 10:Primary bronchi 11:Larynx
1:Trachea 2:Pulmonary artery 3:Pulmonary vein 4:Alveolar duct 5:Alveoli 6:Cardiac notch 7:Bronchioles 8:Tertiary bronchi 9:Secondary bronchi 10:Primary bronchi 11:Larynx

Human lungs are located in two cavities on either side of the heart. Though similar in appearance, the two are not identical. Both are separated into lobes, with three lobes on the right and two on the left. In Anatomy, a lobe is a clear anatomical division or extension that can be determined without the use of a Microscope (at the Gross anatomy level The lobes are further divided into segments, then lobules, hexagonal divisions of the lungs that are the smallest subdivision visible to the naked eye. The connective tissue that divides lobules is often blackened in smokers and city dwellers. The medial border of the right lung is nearly vertical, while the left lung contains a cardiac notch. The anterior border of the Right lung is almost vertical and projects into the Costomediastinal sinus; that of the Left lung presents below an angular notch the The cardiac notch is a concave impression molded to accommodate the shape of the heart. Lungs are to a certain extent 'overbuilt' and have a tremendous reserve volume as compared to the oxygen exchange requirements when at rest. This is one of the the reasons that individuals can smoke for years without having a noticeable decrease in lung function while still or moving slowly; in situations like these only a small portion of the lungs are actually perfused with blood for gas exchange. As oxygen requirements increase due to exercise, a greater volume of the lungs is perfused, allowing the body to match its CO2/O2 exchange requirements. Carbon dioxide ( Chemical formula:) is a Chemical compound composed of two Oxygen Atoms covalently bonded to a single Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the

The environment of the lung is very moist, which makes it hospitable for bacteria. The Bacteria ( singular: bacterium) are a large group of unicellular Microorganisms Typically a few Micrometres in length bacteria have Many respiratory illnesses are the result of bacterial or viral infection of the lungs. A virus (from the Latin virus meaning Toxin or Poison) is a sub-microscopic infectious agent that is unable An infection is the detrimental Colonization of a host Organism by a foreign Species.

Avian lungs

Avian lungs do not have alveoli, as mammalian lungs do, but instead contain millions of tiny passages known as para-bronchi, connected at both ends by the dorsobronchi and that the airflow through the avian lung always travels in the same direction - posterior to anterior. Birds ( class Aves) are bipedal endothermic ( Warm-blooded) Vertebrate animals that lay eggs. Bird anatomy, or the physiological structure of Birds This is in contrast to the mammalian system, in which the direction of airflow in the lung is tidal, reversing between inhalation and exhalation. By utilizing a unidirectional flow of air, avian lungs are able to extract a greater concentration of oxygen from inhaled air. Birds are thus equipped to fly at altitudes at which mammals would succumb to hypoxia, and this also allows them to sustain a higher metabolic rate than an equivalent weight mammal. Chronic Hypoxia is a pathological condition in which the body as a whole ( generalized hypoxia) or region of the body ( tissue hypoxia) is deprived of adequate Metabolism is the set of Chemical reactions that occur in living Organisms in order to maintain Life. Because of the complexity of the system, misunderstanding is common and it is incorrectly believed that that it takes two breathing cycles for air to pass entirely through a bird's respiratory system. A bird's lungs do not store air in either of the sacs between respiration cycles, air moves continuously from the posterior to anterior air sacs throughout respiration. This type of lung construction is called circulatory lungs as distinct from the bellows lung possessed by most other animals.

Reptilian lungs

Reptilian lungs are typically ventilated by a combination of expansion and contraction of the ribs via axial muscles and buccal pumping. Reptiles, or members of the class Reptilia are air-breathing Cold-blooded Vertebrates that have skin covered in scales as opposed to hair or feathers Crocodilians also rely on the hepatic piston method, in which the liver is pulled back by a muscle anchored to the pubic bone (part of the pelvis), which in turn pulls the bottom of the lungs backward, expanding them. Crocodilia is an order of large Reptiles that appeared about 84 million years ago in the late Cretaceous Period ( Campanian stage The liver is a vital organ in the human body and is present in Vertebrates and some other animals

Amphibian lungs

The lungs of most frogs and other amphibians are simple balloon-like structures, with gas exchange limited to the outer surface area of the lung. This article is about the block cipher algorithm For the ultrafast laser pulse measurement technique see Frequency-resolved optical gating. Prehistoric amphibian Amphibians (class Amphibia such as Frogs Toads Salamanders Newts Gymnophiona, Sirens and This is not a very efficient arrangement, but amphibians have low metabolic demands and also frequently supplement their oxygen supply by diffusion across the moist outer skin of their bodies. Unlike mammals, which use a breathing system driven by negative pressure, amphibians employ positive pressure. Positive pressure is a pressure within a system that is greater than the environment that surrounds that system The majority of salamander species are lungless salamanders which conduct respiration through their skin and the tissues lining their mouth. Lungless salamanders (family Plethodontidae) are distinguished from other families of Salamanders by the following traits No lungs The only other known lungless tetrapods are also amphibians — the Bornean Flat-headed Frog (Barbourula kalimantanensis) and Atretochoana eiselti, a caecilian. Tetrapods ( Greek τετραποδη tetrapoda, Latin Quadruped, "four-footed" are Vertebrate Animals UserPolbot. -->The Bornean Flat-headed Frog ( Barbourula kalimantanensis) is a species of Toad in the UserPolbot. --> Atretochoana eiselti is a species of Amphibian in the Caeciliidae family Apoda redirects here For the Moth Genus, see Apoda (moth. For the bishop of Carthage see Caecilianus.

Invertebrate lungs

Some invertebrates have "lungs" that serve a similar respiratory purpose, but are not evolutionarily related to, vertebrate lungs. An invertebrate is an Animal lacking a Vertebral column. The group includes 98% of all animal Species — all animals except those in the Chordate Some arachnids have structures called "book lungs" used for atmospheric gas exchange. Arachnids are a class ( Arachnida) of joint-legged Invertebrate Animals in the subphylum Chelicerata. A book lung is a type of Respiration organ used for atmospheric gas exchange and is found in Arachnids such as Scorpions and Spiders Each of these The Coconut crab uses structures called branchiostegal lungs to breathe air and indeed will drown in water, hence it breathes on land and holds its breath underwater. The coconut crab ( Birgus latro) is the largest land-living Arthropod in the world The Pulmonata are an order of snails and slugs that have developed "lungs". The Pulmonata or "pulmonates" are an order (once a Subclass) of Snails and Slugs that have developed a pallial Lung

Origins

The lungs of today's terrestrial vertebrates and the gas bladders of today's fish have evolved from simple sacs (outpocketings) of the esophagus that allowed the organism to gulp air under oxygen-poor conditions. Vertebrates are members of the Subphylum Vertebrata, Chordates with backbones or spinal columns The grouping sometimes includes gas bladder (also fish maw, less accurately swim bladder or air bladder) is an internal organ that contributes to the ability of a Fish Fish are aquatic Vertebrate animals that are typically ectothermic (previously Cold-blooded) covered with scales, and equipped with two Thus the lungs of vertebrates are homologous to the gas bladders of fish (but not to their gills). In Evolutionary biology, homology has come to mean any similarity between characters that is due to their shared ancestry. A gill is an anatomical structure found in many aquatic organisms This is reflected by the fact that the lungs of a fetus also develop from an outpocketing of the esophagus and in the case of gas bladders, this connection to the gut continues to exist as the pneumatic duct in more "primitive" teleosts, and is lost in the higher orders. A fetus (or foetus or fœtus) is a developing Mammal or other Viviparous Vertebrate, after the Embryonic stage and The esophagus or oesophagus (see American and British English spelling differences) sometimes known as the gullet, is an organ in Teleostei is one of three infraclasses in class Actinopterygii, the ray-finned fishes (This is an instance of correlation between ontogeny and phylogeny. Ontogeny and Phylogeny is Stephen Jay Gould's first technical book published in 1977 by Belknap a division of Harvard University Press. ) There are currently no known animals which have both a gas bladder and lungs.

See also

Further reading

References

Footnotes

  1. ^ a b Gray's Anatomy of the Human Body, 20th ed. Henry Gray's Anatomy of the Human Body (or Gray's Anatomy as it has commonly been shortened is an English-language Human anatomy Textbook 1918.
  2. ^ Wienke B. R.  : "Decompression theory"
  3. ^ Maton, Anthea; Jean Hopkins, Charles William McLaughlin, Susan Johnson, Maryanna Quon Warner, David LaHart, Jill D. Wright (1993). Human Biology and Health. Englewood Cliffs, New Jersey, USA: Prentice Hall. ISBN 0-13-981176-1.  

Dictionary

lung

-noun

  1. A biological organ that extracts oxygen from the air.
© 2009 citizendia.org; parts available under the terms of GNU Free Documentation License, from http://en.wikipedia.org
 Dapyx Software network: MP3 Explorer | Ebook Manager | Zenithic