This article is about a component of dinosaur and bird skeletal systems. For the structures in mammalian lungs, see air sac (lung).
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[clarification needed] in the pneumatization (presence of air) in their bones.[1] Birds use air sacs for respiration as well as a number of other things.[2] 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.[3] 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.[4][5]
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^Schwarz-Wings D, Meyer CA, Frey E, Manz-Steiner HR, Schumacher R (January 2010). "Mechanical implications of pneumatic neck vertebrae in sauropod dinosaurs". Proceedings. Biological Sciences. 277 (1678): 11–17. doi:10.1098/rspb.2009.1275. PMC 2842622. PMID 19801376.
Airsacs are spaces within an organism where there is the constant presence of air. Among modern animals, birds possess the most airsacs (9–11), with...
: alveoli, from Latin alveolus, "little cavity"), also known as an airsac or air space, is one of millions of hollow, distensible cup-shaped cavities...
Strategic Air Command (SAC) was a United States Department of Defense Specified Command and a United States Air Force (USAF) Major Command responsible...
Look up sac or SAC in Wiktionary, the free dictionary. SAC or Sac may refer to: Santa Ana College, California, US San Antonio College, Texas, US St. Andrew's...
the rear the posterior thoracic airsac, in the middle the anterior thoracic airsac and in front the clavicular airsac, in that order gradually diminishing...
Airsacculitis, also known as air sacculitis, aerosacculitis, airsac disease, airsac infection, airsac syndrome and simply sac disease, is a common inflammatory...
respiratory system had efficient unidirectional "flow-through" breathing using airsacs, which hollowed out their bones to an extreme extent. Pterosaurs spanned...
millions of small airsacs; in mammals and reptiles, these are called alveoli, and in birds, they are known as atria. These microscopic airsacs have a very...
airsacs are connected to the airways of the respiratory system, and the pelican can keep its airsacs inflated by closing its glottis, but how air sacs...
constructed for their size and contained openings for airsacs (pneumatization). Such airsacs were at the time known only in birds and pterosaurs, and...
argued against the presence of airsacs in dinosaurs. Researchers have presented evidence and arguments for airsacs in sauropods, "prosauropods", coelurosaurs...
large gliding and soaring birds tend to have the most. Respiratory airsacs often form air pockets within the semi-hollow bones of the bird's skeleton. The...
a series of airsacs connected to the lungs. The use of airsacs forms the basis for the three main avian respiratory characteristics: Air is able to flow...
the airsacs. Air then travels continuously from the airsacs at the back, through the lungs, which are relatively fixed in size, to the airsacs at the...
Forces in Europe (USAFE), Strategic Air Command (SAC), and Air Mobility Command (AMC). The origins of the United States Air Force in the UK can be traced to...
the gular skin (or gular sac or throat sac) is used dramatically. During courtship display, the male forces air into the sac, causing it to inflate over...
Shared tetanuran features include a ribcage indicating a sophisticated air-sac-ventilated lung system similar to that in modern birds. This character...
unit of the Cold War–era Strategic Air Command (SAC). It holds the lineage, history and honors of SAC. See: Strategic Air Command for history prior to 2009...
nose and mouth.[clarification needed] Air is then expelled from the lungs, through the larynx, and into the vocal sac. The vibrations of the larynx emits...
presence of air spaces within bones. It is generally produced during development by excavation of bone by pneumatic diverticula (airsacs) from an air-filled...
Pulmonary alveolus, an airsac in the lungs Alveolar cell or pneumocyte Alveolar duct Alveolar macrophage Mammary alveolus, a milk sac in the mammary glands...
signal that they are producing fecal sacs. For example, nestling curve-billed thrashers raise their posteriors in the air, while young cactus wrens shake their...
Brontosaurus possessed a whip-like structure. The tail also bears an extensive air-sac system to lighten its weight, as observed in specimens of B. parvus. Several...
assets of SAC under one wing at Beale AFB, California, with the RC-135 assets assigned to the 6th Strategic Wing|6th Air Refueling Wing at Eilson Air Force...
are available. The term air mattress may also refer to a certain inflatable swimming pool or beach toy, which has an air-sac "pillow" and several (usually...
fixed-volume, non-expansive lungs. A complicated system of valves and airsacs cycles air constantly over the absorption surfaces of the lungs so allowing...
75% of the fresh air bypasses the lungs and flows directly into a posterior airsac which extends from the lungs and connects with air spaces in the bones...
ensuring association of the chorioallantoic membrane, and in allowing for air-sac formation at the blunt end of the egg). This attachment between dissimilar...
Globemaster III long range cargo aircraft. The SAC is based at the Hungarian Defence Forces Pápa Air Base in Western Hungary. Each participating nation...
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