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Air Sacs
Air sacs are spaces within an organism where there is the constant presence of air. Among modern animals, birds possess the most air sacs (9–11), with their extinct dinosaurian relatives showing a great increase in the pneumatization (presence of air) in their bones. Birds use air sacs for respiration as well as a number of other things. Theropods, like '' Aerosteon'', have many air sacs in the body that are not just in bones, and they can be identified as the more primitive form of modern bird airways. Sauropods are well known for the large number of air pockets in their bones (especially vertebra), although one theropod, '' Deinocheirus'', shows a rivalling number of air pockets. Air sacs in birds Air sacs in respiration Birds have a system of air sacs in their ventilation system.Brown, R. E.; Brain, J. D.; Wang, N. (1997). " The avian respiratory system: a unique model for studies of respiratory toxicosis and for monitoring air quality". ''Environmental Health Perspec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bird
Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a four-chambered heart, and a strong yet lightweight Bird skeleton, skeleton. Birds live worldwide and range in size from the bee hummingbird to the common ostrich. There are over 11,000 living species and they are split into 44 Order (biology), orders. More than half are passerine or "perching" birds. Birds have Bird wing, wings whose development varies according to species; the only known groups without wings are the extinct moa and elephant birds. Wings, which are modified forelimbs, gave birds the ability to fly, although further evolution has led to the Flightless bird, loss of flight in some birds, including ratites, penguins, and diverse endemism, endemic island species. The digestive and respiratory systems of birds are also uniquely a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Secretory Cell
Secretion is the movement of material from one point to another, such as a secreted chemical substance from a cell or gland. In contrast, excretion is the removal of certain substances or waste products from a cell or organism. The classical mechanism of cell secretion is via secretory portals at the plasma membrane called porosomes. Porosomes are permanent cup-shaped lipoprotein structures embedded in the cell membrane, where secretory vesicles transiently dock and fuse to release intra-vesicular contents from the cell. Secretion in bacterial species means the transport or translocation of effector molecules. For example: proteins, enzymes or toxins (such as cholera toxin in pathogenic bacteria e.g. ''Vibrio cholerae'') from across the interior (cytoplasm or cytosol) of a bacterial cell to its exterior. Secretion is a very important mechanism in bacterial functioning and operation in their natural surrounding environment for adaptation and survival. In eukaryotic cells Mecha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Birdsong
Bird vocalization includes both bird calls and bird songs. In non-technical use, bird songs (often simply ''birdsong'') are the bird sounds that are melodious to the human ear. In ornithology and birding, songs (relatively complex vocalizations) are distinguished by function from calls (relatively simple vocalizations). Definition The distinction between songs and calls is based upon complexity, length, and context. Songs are longer and more complex and are associated with Territory (animal), territory and Bird#Breeding, courtship and mating, while calls tend to serve such functions as Alarm signal, alarms or keeping members of a herd, flock in contact. Other authorities such as Howell and Webb (1995) make the distinction based on function, so that short vocalizations, such as those of pigeons, and even non-vocal sounds, such as the drumming of woodpeckers and the "Drumming (snipe), winnowing" of snipes' wings in display flight, are considered songs. Still others require song ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxygen
Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), nonmetal, and a potent oxidizing agent that readily forms oxides with most elements as well as with other chemical compound, compounds. Oxygen is abundance of elements in Earth's crust, the most abundant element in Earth's crust, making up almost half of the Earth's crust in the form of various oxides such as water, carbon dioxide, iron oxides and silicates.Atkins, P.; Jones, L.; Laverman, L. (2016).''Chemical Principles'', 7th edition. Freeman. It is abundance of chemical elements, the third-most abundant element in the universe after hydrogen and helium. At standard temperature and pressure, two oxygen atoms will chemical bond, bind covalent bond, covalently to form dioxygen, a colorless and odorless diatomic gas with the chemical formula ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diving Bird
Diving birds are birds which plunge into the water to catch fish or other prey. Description Such birds may enter the water from flight, such as pelicans, gannets and tropicbirds; or they may dive from the surface of the water, such as the diving ducks, cormorants and penguins. It is theorized that they evolved from birds already adapted for aquatic locomotion, swimming that were equipped with such adaptations as Bird feet and legs#Webbing and lobation, lobed or webbed feet for Animal locomotion, propulsion. Foot-propelled diving birds Some diving birds, for example the extinct Hesperornithes of the Cretaceous Period, propelled themselves with their feet. They were large, streamlined, and flightless birds with teeth for grasping slippery prey. Today, cormorants (family Phalacrocoracidae), loons (Gaviidae), and grebes (Podicipedidae) are the major groups of foot-propelled diving birds. Wing-propelled diving birds Other diving birds are wing-propelled; penguins (Sphenisciformes), dip ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Emperor Penguin Manchot Empereur
The word ''emperor'' (from , via ) can mean the male ruler of an empire. ''Empress'', the female equivalent, may indicate an emperor's wife (empress consort), mother/grandmother (empress dowager/grand empress dowager), or a woman who rules in her own right and name (empress regnant or ''suo jure''). Emperors are generally recognized to be of the highest monarchic honour and royal and noble ranks, rank, surpassing king. In Europe, the title of Emperor has been used since the Middle Ages, considered in those times equal or almost equal in dignity to that of Pope due to the latter's position as visible head of the Church and spiritual leader of the Catholic part of Western Europe. The emperor of Japan is the only currently List of current sovereign monarchs, reigning monarch whose title is translated into English as "Emperor". Both emperors and kings are monarchs or sovereigns, both emperor and empress are considered monarchical titles. In as much as there is a strict definitio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Loon
Loons (North American English) or divers (British English, British / Irish English) are a group of aquatic birds found in much of North America and northern Eurasia. All living species of loons are members of the genus ''Gavia'', family (biology), family Gaviidae and order (biology), order Gaviiformes. Description Loons, which are the size of large ducks or small goose, geese, resemble these birds in shape when swimming. Like ducks and geese, but unlike coots (which are Rallidae) and grebes (Podicipedidae), the loon's toes are connected by Bird feet and legs#Webbing and lobation, webbing. The loons may be confused with the cormorants (Phalacrocoracidae), but can be distinguished from them by their distinct call. Cormorants are not-too-distant relatives of loons, and like them are heavy-set birds whose bellies, unlike those of ducks and geese, are submerged when swimming. Loons in flight resemble plump geese with seagulls' wings that are relatively small in proportion to their bu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Penguin
Penguins are a group of aquatic flightless birds from the family Spheniscidae () of the order Sphenisciformes (). They live almost exclusively in the Southern Hemisphere. Only one species, the Galápagos penguin, is equatorial, with a small portion of its population extending slightly north of the equator (within a quarter degree of latitude). Highly adapted for life in the ocean water, penguins have countershaded dark and white plumage and flippers for swimming. Most penguins feed on krill, fish, squid and other forms of sea life which they catch with their bills and swallow whole while swimming. A penguin has a spiny tongue and powerful jaws to grip slippery prey. They spend about half of their lives on land and the other half in the sea. The largest living species is the emperor penguin (''Aptenodytes forsteri''): on average, adults are about tall and weigh . The smallest penguin species is the little blue penguin (''Eudyptula minor''), also known as the fairy pen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Appendicular Skeleton
The appendicular skeleton is the portion of the vertebrate endoskeleton consisting of the bones, cartilages and ligaments that support the paired appendages ( fins, flippers or limbs). In most terrestrial vertebrates (except snakes, legless lizards and caecillians), the appendicular skeleton and the associated skeletal muscles are the predominant locomotive structures. There are 126 bones in the human appendicular skeleton, includes the skeletal elements within the shoulder and pelvic girdles, upper and lower limbs, and hands and feet. These bones have shared ancestry (are homologous) to those in the forelimbs and hindlimbs of all other tetrapods, which are in turn homologous to the pectoral and pelvic fins in fish. Etymology The adjective "appendicular" comes from Latin ''appendicula'', meaning "small addition". It is the diminutive of ''appendix'', which comes from the prefix ''ad-'' (meaning "to") + and the word root ''pendere'' (meaning "to hang", from PIE root ''* ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synsacrum
The synsacrum is a skeletal structure of birds and other dinosaurs, pterosaurs, as well as xenarthran mammals, in which the sacrum is extended by incorporation of additional fused or partially fused caudal or lumbar In tetrapod anatomy, lumbar is an adjective that means of or pertaining to the abdominal segment of the torso, between the diaphragm (anatomy), diaphragm and the sacrum. Naming and location The lumbar region is sometimes referred to as the lowe ... vertebrae. Some posterior thoracic vertebrae, the lumbar, sacral and a few anterior caudal vertebrae are fused to form a complex bone called synsacrum. In birds, inate bones are fused with the synsacrum to a greater or lesser extent, according to species, forming an avian pelvis. This forms a more extensive rigid structure than the pelvis of a mammal, fulfilling requirements for flight, locomotion and respiration. Posterior to the bird synsacrum there are a few free caudal vertebrae, the last of which is the pygostyl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lung Compliance
Lung compliance, or pulmonary compliance, is a measure of the lung's ability to stretch and expand (distensibility of elastic tissue). In clinical practice it is separated into two different measurements, static compliance and dynamic compliance. Static lung compliance is the change in volume for any given applied pressure. Dynamic lung compliance is the compliance of the lung at any given time during actual movement of air. Low compliance indicates a stiff lung (one with high elastic recoil) and can be thought of as a thick balloon – this is the case often seen in fibrosis. High compliance indicates a pliable lung (one with low elastic recoil) and can be thought of as a grocery bag – this is the case often seen in emphysema. Compliance is highest at moderate lung volumes, and much lower at volumes which are very low or very high. The compliance of the lungs demonstrate lung hysteresis; that is, the compliance is different on inspiration and expiration for identical volume. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pressure Gradient
In hydrodynamics and hydrostatics, the pressure gradient (typically of air but more generally of any fluid) is a physical quantity that describes in which direction and at what rate the pressure increases the most rapidly around a particular location. The pressure gradient is a dimensional quantity expressed in units of pascals per metre (Pa/m). Mathematically, it is the gradient of pressure as a function of position. The gradient of pressure in hydrostatics is equal to the ''body force density'' (generalised Stevin's Law). In petroleum geology and the petrochemical sciences pertaining to oil wells, and more specifically within hydrostatics, pressure gradients refer to the gradient of vertical pressure in a column of fluid within a wellbore and are generally expressed in pounds per square inch per foot (psi/ft). This column of fluid is subject to the compound pressure gradient of the overlying fluids. The path and geometry of the column is totally irrelevant; only the vertical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
