Sentences Generator
And
Your saved sentences

No sentences have been saved yet

236 Sentences With "air sacs"

How to use air sacs in a sentence? Find typical usage patterns (collocations)/phrases/context for "air sacs" and check conjugation/comparative form for "air sacs". Mastering all the usages of "air sacs" from sentence examples published by news publications.

type: All Declarative Interrogative Exclamative

structure: All Simple Compound Complex Compound-Complex

length: All <=10 words 10-20 words 20-30 words 30-50 words

Mold, the CDC says, triggers coughing, wheezing and inflammation of air sacs.
As the need for more air sacs grew, they infiltrated into bone structures.
Classic dinosaur skeletons show the air sacs in bones, just like modern birds.
Pneumonia is when air sacs in the lungs fill with fluid or pus.
Plus forcing air into the lungs can cause inflammation or damage the air sacs.
The lungs become inflamed, while our air sacs become flooded with fluid and pus.
Pneumonia is an infection that causes inflammation in the air sacs of the lungs.
These air sacs, called alveoli, can fill with fluid, making it difficult to breathe.
The virus can also cause inflammation in the air sacs at the bottom of lungs.
For additional buoyancy, pterosaurs had large air sacs dispersed around their muscles and throughout their body.
Pneumonia occurs when the air sacs, or alveoli, of the lungs fill with fluid or pus.
The lungs' air sacs become inflamed, and fill up with fluid or pus instead of air.
All insects have these, and some have air sacs, to store and pump air, as grasshoppers do.
Over subsequent nights they sit in or near their bowls, inflate specialised air sacs, and emit deep booms.
The L virus seems to target and kill the cells that line the tiny air sacs, or alveoli.
Dead cells slough off into the airways, blocking them further, and fluids leak into the lungs' air sacs.
The virus can inflame the lining of the lungs and the air sacs at the bottom of the lungs.
The lipid layer collects those invaders and toxins, binding to them and preventing them from reaching the air sacs.
Pneumonia, which causes inflammation in the air sacs of the lungs, has been another common side effect of contracting coronavirus.
The alveoli (air sacs at the end of the breathing tubes in your lungs) can become inflamed and fill with fluid.
The intermittent water bodies targeted by the new rules function like alveoli -- the tiny air sacs that make our lungs work.
Treatment for severe emphysema, which damages air sacs in the lungs and limits patients breathing ability, is currently limited to capsules and inhalers.
Treatment for severe emphysema, which damages air sacs in the lungs and limits patients' breathing ability, is currently limited to capsules and inhalers.
Dinosaurs, on the other hand, get a second wave of oxygen to absorb when they release the stored fresh air from their air sacs.
In similar cases involving cocaine, the walls of the lungs' air sacs break down and fill with blood, "preventing air exchange," Dr. Fowler wrote.
It could disrupt a substance called surfactant, which helps keep open tiny air sacs deep in the lungs and is essential for normal breathing.
Alveoli is the name of the tiny air sacs clustered in bunches inside the lungs where the gas exchange of oxygen and carbon dioxide takes place.
Those cells can cause air sacs in the lungs, known as alveoli, to become inflamed or fill with fluid and pus, causing the symptoms of pneumonia.
Researchers have suggested that it might disrupt a natural substance in the lungs called surfactant, which helps keep air sacs open and is essential for breathing.
Should pneumonia continue unchecked, it can progress to acute respiratory distress syndrome (ARDS), a condition in which the lung's air sacs lose their ability to intake oxygen.
They often hunt small, schooling fish in flocks, each hitting the water at 60 miles per hour, its brain protected by specialized air sacs in the skull.
According to the National Institutes of Health, the condition is caused when bacteria or a virus enter the lungs, causing a buildup of fluid in the air sacs.
Doctors, artists, and engineers teamed up to create Graham, a mock-up of this supposed human who has no neck but does have air sacs on his ribcage.
Inflamed air sacs also prevent lungs from getting enough oxygen into the bloodstream and removing the byproduct carbon dioxide, The Guardian reported, citing John Wilson, a respiratory physician.
We worry about the really small ones, because they can penetrate down to the alveoli, all the air sacs of the lungs, and then go into your bloodstream.
Dr. Harrison and Dr. Socha first noticed a problem while they were doing synchrotron X-rays of grasshoppers to study their air sacs, which are a bit like lungs.
And their super lightweight skeletons, hollowed out by air sacs that extended from the lungs, which let them have big skeletons that weren't so bulky that they couldn't move around.
But sometimes, these immune cells cause air sacs to form in the lungs, known as alveoli, to become inflamed or fill with fluids and pus, causing the symptoms of pneumonia.
Dinosaurs, like us, get oxygen out of incoming air that is inhaled, but they also have a system of air sacs that captures and momentarily stores some of the incoming air.
"The coronavirus can destroy the small air sacs in the lungs, preventing them from passing oxygen to the blood — suffocating patients from the inside," the Center for Public Integrity report said.
The most common fatal injury is called a blast lung, because the lungs, which are essentially large air sacs, are so rapidly compressed by this primary blast that the result is sudden death.
Sauropod dinosaurs, for example, had limbs like columns to support their massive weight, yet their load was most likely lightened by an avian-like respiration system, which permeated their skeleton with air sacs.
While operating on Hope, vets discovered the broken collarbone pierced one of Hope's air sacs — the large 'throat sac' that orangutans have under their chins and high on their chests — and caused an infection.
However, when the flu turns deadly, it's often because the virus, the bacteria that proliferated in its wake, or both have found their way to the air sacs of our lungs, causing an infection we call pneumonia.
Walking pneumonia -- which isn't actually a medical term -- is not as severe as general pneumonia, which is a serious lung infection that happens when the air sacs in a lung or lungs fill with fluid or pus.
As the study explained, in the more than 2,000 cases of lung illness related to vaping in the U.S., patients see damage to the tiny air sacs that pass oxygen and carbon dioxide in and out of their lungs.
Utah doctors warned that they have seen multiple cases of lipoid pneumonia in patients who vape, which results in fat deposits, potentially from the oil in vaping liquids, being found in the lung's air sacs, the Salt Lake Tribune reported.
According to Mayo Clinic, ARDS "occurs when fluid builds up in the tiny, elastic air sacs (alveoli) in your lungs" which then can inhibit your lungs from filling with enough oxygen, depriving your organs of the oxygen they need to function.
A group of researchers reviewing more than 30 cases of vaping-related injuries found many patients had similar patterns of damage to their lungs, including inflammation, damage to the alveoli (or the lungs' air sacs), and particles of fat in lung tissues known as lipiod pneumonia.
One of the authors, Dr. Anthony Szema, formerly the V.A.'s chief of allergy medicine and now with Hofstra's Zucker School of Medicine, said the carbonaceous and metallic particles that lodged in the air sacs of the mice were identical to those seen in Miller's biopsies.
The doctors diagnosed a 16-year-old boy with hypersensitivity pneumonitis, an immune system response to inhaled dust, mold or chemicals that causes the air sacs and airways in the lungs to become severely inflamed, according to a new report in the medical journal Archives of Disease in Childhood.
An investigation by the State Department of Environmental Conservation found the deaths were caused by aspergillosis, a fungal disease that can infect the lungs and air sacs of waterfowl when they eat moldy grain, such as bread or livestock feed, or agricultural waste, the agency said on Thursday.
The first rays of a new day's sun reveal what is making the noise: large brown birds more than twice the size of a barnyard chicken, strutting and shaking while thrusting bulbous yellow air sacs out of their chests, and fanning a fantastic spread of pointy tail feathers.
You can either freak out because you have to stand in line a few more minutes, or realize that you're standing on a scaffold of bones, breathing through air sacs made of tissue and making sense of it all with a brain so vast it could potentially house the entire Internet.
Dr. Lucey was also influential in the introduction of other important neonatal therapies, including using surfactant, which coats the air sacs, to help the struggling lungs of premature babies; cooling the brains of babies to prevent damage from asphyxiation; and monitoring babies' oxygen levels through the skin, rather than through blood drawn repeatedly from arteries.
Relaxation of these muscles causes inhalation. Three distinct sets of organs perform respiration — the anterior air sacs (interclavicular, cervicals, and anterior thoracics), the lungs, and the posterior air sacs (posterior thoracics and abdominals). Typically there are nine air sacs within the system; however, that number can range between seven and twelve, depending on the species of bird. Passerines possess seven air sacs, as the clavicular air sacs may interconnect or be fused with the anterior thoracic sacs.
Ravens have a high metabolic rate that drives flight. Air flow is directed through the lungs via air sacs. The sacs are used to create a continuous unidirectional flow of fresh air over the respiratory surface. Most birds have nine air sacs, grouped into anterior and posterior sacs, but the common raven as a member of the Passeriformes group only has seven air sacs (missing two cervical air sacs).
As the bird inhales, tracheal air flows through the intrapulmonary bronchi into the posterior air sacs, as well as into the dorsobronchi, but not into the ventrobronchi (Fig. 18). This is due to the bronchial architecture which directs the inhaled air away from the openings of the ventrobronchi, into the continuation of the intrapulmonary bronchus towards the dorsobronchi and posterior air sacs. From the dorsobronchi the inhaled air flows through the parabronchi (and therefore the gas exchanger) to the ventrobronchi from where the air can only escape into the expanding anterior air sacs. So, during inhalation, both the posterior and anterior air sacs expand, the posterior air sacs filling with fresh inhaled air, while the anterior air sacs fill with "spent" (oxygen-poor) air that has just passed through the lungs.
Anatomical dissections of two brown pelicans in 1939 showed that pelicans have a network of subcutaneous air sacs under their skin situated across the ventral surface including the throat, breast, and undersides of the wings, as well as having air sacs in their bones. The air sacs are connected to the airways of the respiratory system, and the pelican can keep its air sacs inflated by closing its glottis, but how air sacs are inflated is not clear. The air sacs serve to keep the pelican remarkably buoyant in the water and may also cushion the impact of the pelican's body on the water surface when they dive from flight into water to catch fish. Superficial air sacs may also help to round body contours (especially over the abdomen, where surface protuberances may be caused by viscera changing size and position) to enable the overlying feathers to form more effective heat insulation and also to enable feathers to be held in position for good aerodynamics.
So, during inhalation, both the posterior and anterior air sacs expand, the posterior air sacs filling with fresh inhaled air, while the anterior air sacs fill with "spent" (oxygen-poor) air that has just passed through the lungs. During exhalation the intrapulmonary bronchi were believed to be tightly constricted between the region where the ventrobronchi branch off and the region where the dorsobronchi branch off. But it is now believed that more intricate aerodynamic features have the same effect. The contracting posterior air sacs can therefore only empty into the dorsobronchi.
On inhalation, air travels to air sacs near the back of a bird. The air then passes through the lungs to air sacs near the front of the bird, from where the air is exhaled. The cross-current respiratory gas exchanger in the lungs of birds. Air is forced from the air sacs unidirectionally (from right to left in the diagram) through the parabronchi.
Aerosteon, a Late Cretaceous allosaur, had the most bird-like air sacs found so far. Early sauropodomorphs, including the group traditionally called "prosauropods", may also have had air sacs. Although possible pneumatic indentations have been found in Plateosaurus and Thecodontosaurus, the indentations are very small. One study in 2007 concluded that prosauropods likely had abdominal and cervical air sacs, based on the evidence for them in sister taxa (theropods and sauropods).
Full text currently online at and Detailed anatomical analyses can be found at Comparison between the air sacs of Majungasaurus and a bird Evidence of air sacs has also been found in theropods. Studies indicate that fossils of coelurosaurs, This is also one of several topics featured in a post on Naish's blog, - note Mirischia was a coelurosaur, which Naish believes was closely related to Compsognathus. ceratosaurs, and the theropods Coelophysis and Aerosteon exhibit evidence of air sacs. Coelophysis, from the late Triassic, is one of the earliest dinosaurs whose fossils show evidence of channels for air sacs.
Researchers have presented evidence and arguments for air sacs in sauropods, "prosauropods", coelurosaurs, ceratosaurs, and the theropods Aerosteon and Coelophysis. In advanced sauropods ("neosauropods") the vertebrae of the lower back and hip regions show signs of air sacs. In early sauropods only the cervical (neck) vertebrae show these features. If the developmental sequence found in bird embryos is a guide, air sacs actually evolved before the channels in the skeleton that accommodate them in later forms.
CT scanning of Aerosteon's fossil bones revealed evidence for the existence of air sacs within the animal's body cavity.
Ten different air sacs attach to the lungs to form areas for respiration. The most posterior air sacs (abdominal and post-thoracic) differ in that the right abdominal air sac is relatively small, lying to the right of the mesentery, and dorsally to the liver. While the left abdominal air sac is large and lies to the left of the mesentery. The connection from the main mesobronchi to the more anterior air sacs including the interclavicular, lateral clavicular, and pre-thoracic sacs known as the ventrobronchi region.
Along with other saurischian dinosaurs (such as theropods, including birds), sauropods had a system of air sacs, evidenced by indentations and hollow cavities in most of their vertebrae that had been invaded by them. Pneumatic, hollow bones are a characteristic feature of all sauropods.Wedel, M.J. (2009). "Evidence for bird-like air sacs in Saurischian dinosaurs".
DIK-1-1 preserves an oval hyoid bone (which supports the tongue) more similar to those of chimps and gorillas than the bar-shaped hyoid of humans and orangutans. This would suggest the presence of laryngeal air sacs characteristic of non-human African apes (and large gibbons). Air sacs may lower the risk of hyperventilating when producing faster extended call sequences by rebreathing exhaled air from the air sacs. The loss of these in humans could have been a result of speech and resulting low risk of hyperventilating from normal vocalisation patterns.
Comparison between the air sacs of Majungasaurus and a bird (duck) Large meat-eating dinosaurs had a complex system of air sacs similar to those found in modern birds, according to an investigation led by Patrick M. O'Connor of Ohio University. In theropod dinosaurs (carnivores that walked on two legs and had birdlike feet) flexible soft tissue air sacs likely pumped air through the stiff lungs, as is the case in birds. "What was once formally considered unique to birds was present in some form in the ancestors of birds", O'Connor said.
Like other early ray-finned fish, Palaeoniscum had air sacs connected to the mouth, which served as a primitive swim bladder.
Glassworms are almost entirely transparent, except for pairs of black kidney-shaped structures in the front and the back of the body. These dots are the air sacs. They use these air sacs to migrate up and down in lakes. Glassworms breathe through the end of their abdomen and have two small eyes at the front of their bodies.
During exhalation the pressure in the posterior air sacs (which were filled with fresh air during inhalation) increases due to the contraction of the oblique muscle described above. The aerodynamics of the interconnecting openings from the posterior air sacs to the dorsobronchi and intrapulmonary bronchi ensures that the air leaves these sacs in the direction of the lungs (via the dorsobronchi), rather than returning down the intrapulmonary bronchi (Fig. 18). From the dorsobronchi the fresh air from the posterior air sacs flows through the parabronchi (in the same direction as occurred during inhalation) into ventrobronchi. The air passages connecting the ventrobronchi and anterior air sacs to the intrapulmonary bronchi direct the "spent", oxygen poor air from these two organs to the trachea from where it escapes to the exterior.
The study concluded that it was impossible to determine whether prosauropods had a bird-like flow-through lung, but that the air sacs were almost certainly present. A further indication for the presence of air sacs and their use in lung ventilation comes from a reconstruction of the air exchange volume (the volume of air exchanged with each breath) of Plateosaurus, which when expressed as a ratio of air volume per body weight at 29 ml/kg is similar to values of geese and other birds, and much higher than typical mammalian values. So far no evidence of air sacs has been found in ornithischian dinosaurs. But this does not imply that ornithischians could not have had metabolic rates comparable to those of mammals, since mammals also do not have 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. 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 number of air pockets in their bones (especially vertebra), although one theropod, Deinocheirus, shows a rivalling number of air pockets.
Steven MithenMithen, Steven (2006). The Singing Neanderthals, believes that H. heidelbergensis and its descendant H. neanderthalensis, acquired a pre- linguistic system of communication. Homo heidelbergensis is thought to have been the first ancestor of modern humans not to have air sacs, which are laryngeal diverticula involved in vocalization. The loss of air sacs may have contributed to humans' ability to develop vocal language.
Recent studies indicate that Massospondylus grew steadily throughout its lifespan, possessed air sacs similar to those of birds, and may have cared for its young.
Air then travels continuously from the air sacs at the back, through the lungs, which are relatively fixed in size, to the air sacs at the front. From here, the air is exhaled. These fixed size lungs are called "circulatory lungs", as distinct from the "bellows-type lungs" found in most other animals. The lungs of birds contain millions of tiny parallel passages called parabronchi.
Comparison between the air sacs of Majungasaurus and a modern bird Scientists have reconstructed the respiratory system of Majungasaurus based on a superbly preserved series of vertebrae (UA 8678) recovered from the Maevarano Formation. Most of these vertebrae and some of the ribs contained cavities (pneumatic foramina) that may have resulted from the infiltration of avian- style lungs and air sacs. In birds, the neck vertebrae and ribs are hollowed out by the cervical air sac, the upper back vertebrae by the lung, and the lower back and sacral (hip) vertebrae by the abdominal air sac. Similar features in Majungasaurus vertebrae imply the presence of these air sacs.
Fig. 15 The arrangement of the air sacs, and lungs in birds Fig. 16 The anatomy of bird's respiratory system, showing the relationships of the trachea, primary and intra-pulmonary bronchi, the dorso- and ventro-bronchi, with the parabronchi running between the two. The posterior and anterior air sacs are also indicated, but not to scale. Fig. 17 A dove skeleton, showing the movement of the chest during inhalation.
Although bird lungs are smaller than those of mammals of comparable size, the air sacs account for 15% of the total body volume, whereas in mammals, the alveoli, which act as the bellows, constitute only 7% of the total body volume. The walls of the air sacs do not have a good blood supply and so do not play a direct role in gas exchange. Birds lack a diaphragm, and therefore use their intercostal and abdominal muscles to expand and contract their entire thoraco-abdominal cavities, thus rhythmically changing the volumes of all their air sacs in unison (illustration on the right). The active phase of respiration in birds is exhalation, requiring contraction of their muscles of respiration.
In 2019 she was elected to the American Society for Clinical Investigation. During the COVID-19 pandemic Calfee studied why SARS-CoV-2 patients experienced such different symptoms; ranging from mild to life-threatening. Her research identified that the infection attacks the alveolar epithelium, small air sacs that usually prevent fluid entering the lungs. When the barrier between the air sacs and blood becomes leaky, fluid starts to pour into the lungs.
Although possible pneumatic indentations have been found in Plateosaurus and Thecodontosaurus, the indentations were very small. One study in 2007 concluded that basal sauropodomorphs like Massospondylus likely had abdominal and cervical air sacs, based on the evidence for them in sister taxa (theropods and sauropods). The study concluded that it was impossible to determine whether basal sauropodomorphs had a bird-like flow-through lung, but that the air sacs were almost certainly present.
The arrangement of the air sacs, and lungs in birds The anatomy of bird's respiratory system, showing the relationships of the trachea, primary and intra-pulmonary bronchi, the dorso- and ventro-bronchi, with the parabronchi running between the two. The posterior and anterior air sacs are also indicated, but not to scale. Inhalation–exhalation cycle in birds. Due to the high metabolic rate required for flight, birds have a high oxygen demand.
The oxygen passes through the tracheae to the tracheoles, and enters the body by the process of diffusion. Carbon dioxide leaves the body by the same process. The major tracheae are thickened spirally like a flexible vacuum hose to prevent them from collapsing and often swell into air sacs. Larger insects can augment the flow of air through their tracheal system, with body movement and rhythmic flattening of the tracheal air sacs.
Top: Sacrum in bottom (A) and right side view (B). Bottom: Right ilium in side view (C) and left coracoid in side view (D). Air sacs not only invaded the vertebrae, but also the ribs. In Brachiosaurus, the air sacs invaded through a small opening on the front side of the rib shafts, while in Giraffatitan openings were present on both the front and back sides of the tuberculum, a bony projection articulating with the diapophyses of the vertebrae.
Northern gannets have streamlined bodies adapted for plunge-diving at high speed, including powerful neck muscles, and a spongy bone plate at the base of the bill. The nostrils are inside the bill and can be closed to prevent water entry; the eyes are protected by strong nictitating membranes. There are subcutaneous air sacs in the lower body and along the sides. Other air sacs are located between the sternum and the pectoral muscles and between the ribs and the intercostal muscles.
In the head, thorax, or abdomen, tracheae may also be connected to air sacs. Many insects, such as grasshoppers and bees, which actively pump the air sacs in their abdomen, are able to control the flow of air through their body. In some aquatic insects, the tracheae exchange gas through the body wall directly, in the form of a gill, or function essentially as normal, via a plastron. Note that despite being internal, the tracheae of arthropods are shed during moulting (ecdysis).
Each pair of dorso-ventrobronchi is connected by a large number of parallel microscopic air capillaries (or parabronchi) where gas exchange occurs. As the bird inhales, tracheal air flows through the intrapulmonary bronchi into the posterior air sacs, as well as into the dorsobronchi (but not into the ventrobronchi whose openings into the intrapulmonary bronchi were previously believed to be tightly closed during inhalation. However, more recent studies have shown that the aerodynamics of the bronchial architecture directs the inhaled air away from the openings of the ventrobronchi, into the continuation of the intrapulmonary bronchus towards the dorsobronchi and posterior air sacs). From the dorsobronchi the air flows through the parabronchi (and therefore the gas exchanger) to the ventrobronchi from where the air can only escape into the expanding anterior air sacs.
Scientific debate continues regarding the specific ways in which dinosaur temperature regulation evolved. Comparison between the air sacs of an abelisaur and a bird In saurischian dinosaurs, higher metabolisms were supported by the evolution of the avian respiratory system, characterized by an extensive system of air sacs that extended the lungs and invaded many of the bones in the skeleton, making them hollow. Early avian-style respiratory systems with air sacs may have been capable of sustaining higher activity levels than those of mammals of similar size and build. In addition to providing a very efficient supply of oxygen, the rapid airflow would have been an effective cooling mechanism, which is essential for animals that are active but too large to get rid of all the excess heat through their skin.
Reighardia sternae, also known as the larid pentastome, is a small internal parasitic crustacean. It is the only Pentastomida species to use gulls and terns as hosts, living in the body cavity and air sacs.
The air sacs were via tubes connected with the vertebrae. Diverticula filled the various fossae and that formed depressions in the vertebral bone walls. These were again connected with inflexible air cells inside the bones.
These microscopic air sacs have a very rich blood supply, thus bringing the air into close contact with the blood. These air sacs communicate with the external environment via a system of airways, or hollow tubes, of which the largest is the trachea, which branches in the middle of the chest into the two main bronchi. These enter the lungs where they branch into progressively narrower secondary and tertiary bronchi that branch into numerous smaller tubes, the bronchioles. In birds the bronchioles are termed parabronchi.
Its backbone and ribs are typical for dicynodonts, however, the cervical vertebrae of the neck are notable for having unusual hollows excavated into their sides. This is similar to the holes in some dinosaur vertebrae that are associated with a system of air sacs and a bird-like respiratory system. However, unlike dinosaurs Lisowicia lacks openings in its vertebrae (pleurocoels) for air sacs and the interior of the vertebra is solid. This trait is unique to Lisowicia amongst dicynodonts, and its function is unclear.
From there the fresh air from the posterior air sacs flows through the parabronchi (in the same direction as occurred during inhalation) into ventrobronchi. The air passages connecting the ventrobronchi and anterior air sacs to the intrapulmonary bronchi open up during exhalation, thus allowing oxygen-poor air from these two organs to escape via the trachea to the exterior. Oxygenated air therefore flows constantly (during the entire breathing cycle) in a single direction through the parabronchi. The cross-current respiratory gas exchanger in the lungs of birds.
Air flow through the parabronchi of the paleopulmo is in the same direction to the dorsobronchi during inspiration and expiration. Inspired air moves into the respiratory system as a result of the expansion of thoraco abdominal cavity; controlled by inspiratory muscles. During expiration, oxygen poor air flows to the anterior air sacs and is expelled by the action of the expiratory muscles. The common ostrich air sacs play a key role in respiration since they are capacious, and increase surface area (as described by the Fick Principle).
Overall, ostrich respiration can be thought of as a high velocity-low pressure system. At rest, there is small pressure differences between the ostrich air sacs and the atmosphere, suggesting simultaneous filling and emptying of the air sacs. The increase in respiration rate from the low range to the high range is sudden and occurs in response to hyperthermia. Birds lack sweat glands, so when placed under stress due to heat, they heavily rely upon increased evaporation from the respiratory system for heat transfer.
Surfactant metabolism dysfunction is a condition where pulmonary surfactant is insufficient for adequate respiration. Surface tension at the liquid-air interphase in the alveoli makes the air sacs prone to collapsing post expiration. This is due to the fact that water molecules in the liquid-air surface of alveoli are more attracted to one another than they are to molecules in the air. For sphere-like structures like alveoli, water molecules line the inner walls of the air sacs and stick tightly together through hydrogen bonds.
However, this and other early studies of sauropod ecology were flawed in that they ignored a substantial body of evidence that the bodies of sauropods were heavily permeated with air sacs. In 1878, paleontologist E.D. Cope had even referred to these structures as "floats". Beginning in the 1970s, the effects of sauropod air sacs on their supposed aquatic lifestyle began to be explored. Paleontologists such as Coombs and Bakker used this, as well as evidence from sedimentology and biomechanics, to show that sauropods were primarily terrestrial animals.
Previous workers had suggested that non-avian theropods might — like birds — possess post-cranial air sacs, and Mirischia seems to confirm that. Another notable trait is the exceptional thinness of the bone wall of all skeletal elements.
The increase in volume of the entire trunk cavity reduces the air pressure in all the thoraco-abdominal air sacs, causing them to fill with air as described below. During exhalation the external oblique muscle which is attached to the sternum and vertebral ribs anteriorly, and to the pelvis (pubis and ilium in Fig. 17) posteriorly (forming part of the abdominal wall) reverses the inhalatory movement, while compressing the abdominal contents, thus increasing the pressure in all the air sacs. Air is therefore expelled from the respiratory system in the act of exhalation. Fig.
Very few formal rebuttals have been published in scientific journals of Ruben et al.’s claim that dinosaurs could not have had avian-style air sacs; but one points out that the Sinosauropteryx fossil on which they based much of their argument was severely flattened and therefore it was impossible to tell whether the liver was the right shape to act as part of a hepatic piston mechanism. Some recent papers simply note without further comment that Ruben et al. argued against the presence of air sacs in dinosaurs.
Interstitial lung disease (ILD), or diffuse parenchymal lung disease (DPLD), is a group of lung diseases affecting the interstitium (the tissue and space around the alveoli (air sacs of the lungs). It concerns alveolar epithelium, pulmonary capillary endothelium, basement membrane, and perivascular and perilymphatic tissues. It may occur when an injury to the lungs triggers an abnormal healing response. Ordinarily, the body generates just the right amount of tissue to repair damage, but in interstitial lung disease, the repair process goes awry and the tissue around the air sacs (alveoli) becomes scarred and thickened.
Ruben has questioned for many years the theory that birds descend from small carnivorous dinosaurs of suborder Theropoda. He suggest theropods had a diaphragma driven respiratory system which could not have evolved into the complex air sacs in birds (but the presence of air sacs in saurischian dinosaurs has been demonstrated by highly pneumatic fossil bones of e.g. Aerosteon and Tataouinea). While some have claimed Ruben's research to be flawed, his papers have, nevertheless, appeared in highly regarded, heavily peer-reviewed journals such as Science, Nature and the Journal of Morphology.
The abdominal tracheal air sacs surround the sound muscles and extend into the abdomen, acting as resonant chambers to amplify sound. The floury baker rapidly extends or raises its abdomen, thus modulating the influence of the air sacs on the sound to change its volume, pitch or tune during the introduction to the free song. This can be heard when a cicada is undisturbed in its natural environment, while male cicadas use these calls to attract females. The species is one of Australia's loudest cicadas and has been termed "the best musician of them all".
The pulmonary capillaries surround the parabronchi in the manner shown (blood flowing from below the parabronchus to above it in the diagram). Blood or air with a high oxygen content is shown in red; oxygen-poor air or blood is shown in various shades of purple-blue. The lungs of birds are relatively small, but are connected to 8 or 9 air sacs that extend through much of the body, and are in turn connected to air spaces within the bones. On inhalation, air travels through the trachea of a bird into the air sacs.
Small sacs called atria radiate from the walls of the tiny passages; these, like the alveoli in other lungs, are the site of gas exchange by simple diffusion. The blood flow around the parabronchi and their atria forms a cross-current process of gas exchange (see diagram on the right). The air sacs, which hold air, do not contribute much to gas exchange, despite being thin-walled, as they are poorly vascularised. The air sacs expand and contract due to changes in the volume in the thorax and abdomen.
Something similar occurs with the respiratory system. In mammals, the total inner volume of lungs changes during ventilation. However, this does not happen in birds. They make the air circulate through their lungs by contracting and expanding their air sacs.
The common ostrich is an endotherm and maintains a body temperature of in its extreme living temperature conditions, such as the heat of the savanna and desert regions of Africa. The ostrich utilizes its respiratory system via a costal pump for ventilation rather than a diaphragmatic pump as seen in most mammals. Thus, they are able to use a series of air sacs connected to the lungs. The use of air sacs forms the basis for the three main avian respiratory characteristics: # Air is able to flow continuously in one direction through the lung, making it more efficient than the mammalian lung.
Fusions of individual bones into strong, rigid structures are characteristic. Most major bird bones are extensively pneumatized. They contain many air pockets connected to the pulmonary air sacs of the respiratory system. Their spongy interior makes them strong relative to their mass.
The nasal crest of Kritosaurus, whatever its true form, may have been used for a variety of social functions, such as identification of sexes or species and social ranking. There may have been inflatable air sacs flanking it for both visual and auditory signaling.
In strong flyers like cranes and falcons, the arms of the furcula are large, hollow and quite rigid.The Inner Bird: Anatomy and Evolution, by Gary W. Kaiser In birds, the furcula also may aid in respiration by helping to pump air through the air sacs.
They contain numerous sporophylls arranged in whorls or spirals. Each has four to 20 elongated pollen sacs attached to the lower surface at one end. The pollen grains are round and do not possess wings or air sacs. Female cones are also very large.
Ancestors such as Australopithecus afarensis did have air sacs, as do other great apes. Furthermore, there is evidence that Homo heidelbergensis was right-handed. Handedness is associated with the development of language among hominins. Considering this evidence, scientists have hypothesized about the speaking capabilities of the species.
The remaining neck vertebrae were weakly opisthocoelous, i.e. with a convex front of the vertebral body and a concave rear. The vertebral bodies had single pleurocoels, pneumatic depressions created by air sacs, on their sides. The vertebral bodies of the torso were robust but with a narrow waist.
Birds' lungs obtain fresh air during both exhalation and inhalation, because the air sacs do all the "pumping" and the lungs simply absorb oxygen. From about 1870 onwards scientists have generally agreed that the post-cranial skeletons of many dinosaurs contained many air-filled cavities (postcranial skeletal pneumaticity), especially in the vertebrae. Pneumatization of the skull (such as paranasal sinuses) is found in both synapsids and archosaurs, but postcranial pneumatization is found only in birds, non-avian saurischian dinosaurs, and pterosaurs. For a long time these cavities were regarded simply as weight-saving devices, but Bakker proposed that they were connected to air sacs like those that make birds' respiratory systems the most efficient of all animals'.
The vertebral column in dinosaurs consists of the cervical (neck), dorsal (back), sacral (hips), and caudal (tail) vertebrae. Saurischian dinosaur vertebrae sometimes possess features known as pleurocoels, which are hollow depressions on the lateral portions of the vertebrae, perforated to create an entrance into the air chambers within the vertebrae, which served to decrease the weight of these bones without sacrificing strength. These pleurocoels were filled with air sacs, which would have further decreased weight. In sauropod dinosaurs, the largest known land vertebrates, pleurocoels and air sacs may have reduced the animal's weight by over a ton in some instances, a handy evolutionary adaption in animals that grew to over 30 metres in length.
Such spaces, which are also found in modern theropods (that is, the birds), are interpreted as having held air sacs used in respiration. The rib cage was broad, giving it a barrel chest, especially in comparison to less derived theropods like Ceratosaurus.Paul, Gregory S. (1988). Predatory Dinosaurs of the World. 277.
Some species of mites have adapted to infesting the internal tissues and organs of their hosts. Cytodites nudus is a typical species of this type; it infests the air-sacs of birds. Laminosioptes cysticola , the fowl cyst mite is another species of mite internally infesting birds. It has a worldwide distribution.
Sounds also bounce off the skull and air sacs that surround the melon.Marine Mammal Biology: An Evolutionary Approach. pg 153 Melon size is unrelated to maximum dive depth in toothed whales. The particular characteristics of the melon probably have more to do with odontocete phylogeny, the taxonomic relationships over evolutionary time.
This is one of the factors that may limit their size. A tracheal tube may contain ridge-like circumferential rings of taenidia in various geometries such as loops or helices. Taenidia provide strength and flexibility to the trachea. In the head, thorax, or abdomen, tracheae may also be connected to air sacs.
Small for a sauropod, Nigersaurus was about long, and had a short neck. It weighed around , comparable to a modern elephant. Its skeleton was highly pneumatised (filled with air spaces connected to air sacs), but the limbs were robustly built. Its skull was very specialised for feeding, with large fenestrae and thin bones.
The spine comprised 10 cervical (neck) vertebrae; 14 dorsal (trunk) vertebrae; three sacral (hip) vertebrae; and ca. 50 caudal (tail) vertebrae. In contrast to the later sauropods, the sides of the dorsal vertebrae did not show deep cavities caused by air sacs invading the bone (). The scapula (shoulder blade) was hourglass- shaped.
The actual traps are held by petioles which hold air sacs that aid in flotation. One end of the stem continually grows while the other end dies off. Growth is quite rapid ( per day in Japanese populations), so that in optimal conditions a new whorl is produced once or more each day.
Surfactant protein B is an essential lipid-associated protein found in pulmonary surfactant. Without it, the lung would not be able to inflate after a deep breath out. It rearranges lipid molecules in the fluid lining the lung so that tiny air sacs in the lung, called alveoli, can more easily inflate.
The combination of actinofibrils and muscle layers may have allowed the animal to adjust the wing slackness and camber. As shown by cavities in the wing bones of larger species and soft tissue preserved in at least one specimen, some pterosaurs extended their system of respiratory air sacs into the wing membrane.
Dorsal vertebrae of the holotype; the openings at their lower sides are , through which air sacs invaded the bone and connected with air cells inside The respiration system of sauropods, like that of birds, made use of air sacs. There was not a bidirectional airflow as with mammals, in which the lungs function as bellows, first inhaling and then exhaling air. Instead the air was sucked from the trachea into an abdominal air sac in the belly which then pumped it forward through the parabranchi, air loops, of the stiff lung. Valves prevented the air from flowing backward when the abdominal air sac filled itself again; at the same time a cervical air sac at the neck base sucked out the spent air from the lung.
Mites were recovered from the autosomal air sacs of bumble bees. These mites can affect behavior and reduce longevity, which may cause further stress to colonies already facing difficulties. Conopid flies also parasitize B. bimaculatus. Male bees were less likely to be parasitized than workers, and larger bees were more likely to be parasitized than smaller bees.
The capillaries are responsible for allowing the blood to receive oxygen through tiny air sacs in the lungs. This is also the site where carbon dioxide exits the blood. This all occurs in the lungs where blood is oxygenated. The blood pressure in blood vessels is traditionally expressed in millimetres of mercury (1 mmHg = 133 Pa).
Bart de Boer in 2017 acknowledges this ambiguity of a universally accepted Neanderthal vocal tract, however he notes the similarities in the thoracic vertebral canal, potential air sacs, and hyoid bones between modern humans and Neanderthals to suggest the presence of complex speech.de Boer, Bart (2017). "Evolution of speech and evolution of language". Psychonomic Bulletin & Review.
In Apatosaurus louisae, the atlas-axis complex of the first cervicals is nearly fused. The dorsal ribs are not fused or tightly attached to their vertebrae and are instead loosely articulated. Apatosaurus has ten dorsal ribs on either side of the body. The large neck was filled with an extensive system of weight-saving air sacs.
Pneumonia is an inflammatory condition of the lung primarily affecting the small air sacs known as alveoli. Symptoms typically include some combination of productive or dry cough, chest pain, fever and difficulty breathing. The severity of the condition is variable. Pneumonia is usually caused by infection with viruses or bacteria, and less commonly by other microorganisms.
The odontoid may have been encased in a keratinous covering so that it could occlude with the teeth. Apart from the skull, the skeleton of Istiodactylus was similar to those of other ornithocheiroid pterosaurs. The vertebral column, forelimb, and trunk bones were pneumatised by air sacs. The neural arches of the vertebrae had tall, sloping laminae.
Some genera of mites have adapted to infesting the lungs and air-sacs of birds or the lungs of mammals. Cytodites nudus is a typical species of this type. It infests poultry in North America and South Africa and may cause reduction in productivity of the birds. Another genus of similar bird infesting mites is Laminosioptes.
The nasal passage contains nine or ten air sacs, which are capable of sealing off all air within the passage. Behind these are an additional set of vomeronasal sacs. The trachea, however, is short, with only four cartilaginous rings. The stomach has three chambers, with no caecum, and no distinct difference between the small and large intestines.
John Ruben et al. (1997, 1999, 2003, 2004) disputed this and suggested that dinosaurs had a "tidal" respiratory system (in and out) powered by a crocodile-like hepatic piston mechanism – muscles attached mainly to the pubis pull the liver backwards, which makes the lungs expand to inhale; when these muscles relax, the lungs return to their previous size and shape, and the animal exhales. They also presented this as a reason for doubting that birds descended from dinosaurs. Critics have claimed that, without avian air sacs, modest improvements in a few aspects of a modern reptile's circulatory and respiratory systems would enable the reptile to achieve 50% to 70% of the oxygen flow of a mammal of similar size, and that lack of avian air sacs would not prevent the development of endothermy.
Princeton University Press. . Partly, this is due to the presence of air sacs in their wing membranes, and that pterosaurs launched into flight using their front limbs in a quadrupedal stance similar to that of modern bats, a method faster and less energy taxing that the bipedal launching of modern birds.Witton, Mark P. (2013). Pterosaurs: Natural History, Evolution, Anatomy. Princeton University Press. .
Like many birds, it hosts a number of internal and external parasites. The linguatulid species Reighardia sternae, a tiny, worm-like crustacean, is sometimes found in the gull's air sacs. The acanthocephala worm Corynosoma bipapillum is sometimes found in the bird's posterior gut, as is the intestinal worm Echinostomum spinulosum. Gigantobilharzia lawayi, a schistosome (or blood fluke) may be carried in the capillaries.
The Apatosaurus skull, long thought to be similar to Camarasaurus, is much more similar to that of Diplodocus. Apatosaurus was a generalized browser that likely held its head elevated. To lighten its vertebrae, Apatosaurus had air sacs that made the bones internally full of holes. Like that of other diplodocids, its tail may have been used as a whip to create loud noises.
Coelophysids are characterized by slender, skinny builds and long, narrow skulls with large fenestrae to allow for a lighter skull. They are fairly primitive theropods, and so have fairly basal characteristics, such as hollow air sacs in the cervical vertebrae and obligate bipedalism. Their slender builds allowed them to be fast and agile runners. All known members of Coelophysidae are carnivores.
In toothed whales, connective tissue exists in the melon as a head buckle. This is filled with air sacs and fat that aid in buoyancy and biosonar. The sperm whale has a particularly pronounced melon; this is called the spermaceti organ and contains the eponymous spermaceti, hence the name "sperm whale". Even the long tusk of the narwhal is a vice-formed tooth.
However, with this development of hugely improved air sacs in their lungs, air sacculitis has become more prevalent among orangutans in this species. Air sacculitis is similar to streptococcal infection, e.g. strep throat in Homo sapiens. The bacterial infection is becoming increasing common in captive orangutans, due to the fact that they are exposed to the human strain of Streptococcus in captivity.
The nasal passage contains nine or ten air sacs, which have a complicated structure, and are capable of sealing off all air within the passage. Behind these are an additional set of vomeronasal sacs. The trachea, however, is short, with only four cartilaginous rings. The stomach has three chambers, there is no caecum, and no distinct difference between the small and large intestines.
Such air sacs were at the time known only in birds and pterosaurs, and Seeley considered the vertebrae to come from a pterosaur. He named the new genus Ornithopsis, or "bird face" because of this. When more complete specimens of Cetiosaurus were described by Phillips in 1871, he finally recognized the animal as a dinosaur related to Pelorosaurus.Phillips, J. (1871).
Both the southern and the horned screamer remain widespread and are overall fairly common. In contrast, the northern screamer is relatively rare and consequently considered near threatened. They are seldom hunted, in spite of their conspicuous nature, because their flesh has a spongy texture and is riddled with air-sacs, making it highly unpalatable. The main threats are habitat destruction and increased intensification of agriculture.
The respiratory system of birds differs significantly from that found in mammals. Firstly, they have rigid lungs which do not expand and contract during the breathing cycle. Instead an extensive system of air sacs (Fig. 15) distributed throughout their bodies act as the bellows drawing environmental air into the sacs, and expelling the spent air after it has passed through the lungs (Fig. 18).
Childhood interstitial lung disease, sometimes abbreviated as ChILD, is a family of rare chronic and complex disorders that affect the lungs of children. In the lungs, these disorders affect the interstitium, which is the space around the alveoli. The alveoli are the air sacs of the lungs. Not all types of interstitial lung disease that occur in adults occur also in children, and vice versa.
Respiratory bronchioles, the earliest structures that will contain alveoli, have formed by 16 weeks of gestation; the cells that will become the alveoli begin to appear at the end of these bronchioles. Around week 20, fetal breathing movements may begin. Alveolar sacs are formed at 32 weeks of gestation, and these air sacs continue to form until 8 years of age and possibly into the teenage years.
In Meester, J. and H.W. Setzer (eds.) The mammals of Africa: an identification manual. Smithsonian Institution Press, Washington, D.C. This species is named for erectable epaulettes of hair that form around large scent glands in males only. Males are also distinguished from females by air sacs on the neck that may increase the volume of courtship calls. Scent glands are located near the white ear patches in both sexes.
The sixth cervical vertebra is the longest, being four times longer than tall. The neck vertebrae generally have a simplified structure, as exemplified by the lack of rear epipophyses. Most are not pneumatised by pleurocoels, depressions in which diverticula of air sacs penetrate the bone walls. On the front neck, the neural spines, normally rectangular plates, have been reduced to a low ridge; more to behind they have disappeared.
Micrograph of diffuse alveolar damage, the histologic correlate of ARDS. H&E; stain. ARDS is a form of fluid accumulation in the lungs not explained by heart failure (noncardiogenic pulmonary edema). It is typically provoked by an acute injury to the lungs that results in flooding of the lungs' microscopic air sacs responsible for the exchange of gases such as oxygen and carbon dioxide with capillaries in the lungs.
Their highly effective respiratory system helps them meet that demand. Although birds have lungs, theirs are fairly rigid structures that do not expand and contract as they do in mammals, reptiles and many amphibians. Instead, the structures that act as the bellows that ventilate the lungs are the air sacs, which are distributed throughout much of the birds' bodies. The airsacs move air unidirectionally through the parabronchi of the rigid lungs.
Though this plays a role in reducing the weight of the animal, Wedel (2003) states they are also likely connected to air sacs, as in birds. James Spotila et al. (1991) concludes that the large body size of sauropods would have made them unable to maintain high metabolic rates because they would not have been able to release enough heat. They assumed sauropods had a reptilian respiratory system.
Tetrao cupido drawn by T. W. Wood for second edition of Darwin's The Descent of Man, 1874 Greater prairie chickens do not migrate. They are territorial birds and often defend their booming grounds. These booming grounds are the area in which they perform their displays in hopes of attracting females. Their displays consist of inflating air sacs located on the side of their neck and snapping their tails.
The advantage of this thick barrier may be protection from damage by large volumes of blood flow in times of activity, such as running, since air is pumped by the air sacs rather than the lung itself. As a result, the capillaries in the parabronchi have thinner walls, permitting more efficient gaseous exchange. In combination with separate pulmonary and systemic circulatory systems, it helps to reduce stress on the BGB.
TB infection begins when the mycobacteria reach the alveolar air sacs of the lungs, where they invade and replicate within endosomes of alveolar macrophages. Macrophages identify the bacterium as foreign and attempt to eliminate it by phagocytosis. During this process, the bacterium is enveloped by the macrophage and stored temporarily in a membrane-bound vesicle called a phagosome. The phagosome then combines with a lysosome to create a phagolysosome.
"Non-avian theropod dinosaurs from the early Late Cretaceous of Central Europe." Cretaceous Research 31: 304-320, The type species is Pneumatoraptor fodori, named for Géza Fodor, who provided funding for the dig. The genus name Pneumatoraptor refers to the pneumaticity of the bone, the hollow spaces that would have been filled with air sacs in life. The holotype specimen is identified by the catalog number MTM V.2008.38.1.
The respiratory system of birds differs significantly from that found in mammals, containing unique anatomical features such as air sacs. The lungs of birds also do not have the capacity to inflate as birds lack a diaphragm and a pleural cavity. Gas exchange in birds occurs between air capillaries and blood capillaries, rather than in alveoli. See Avian respiratory system for a detailed description of these and other features.
Many insects, such as grasshoppers and bees, which actively pump the air sacs in their abdomen, are able to control the flow of air through their body. In some aquatic insects, the tracheae exchange gas through the body wall directly, in the form of a gill, or function essentially as normal, via a plastron. Note that despite being internal, the tracheae of arthropods are lined with cuticular tissue and are shed during moulting (ecdysis).
The respiratory tract can be divided into two main components: the conducting airways and the gas exchange airways. The gas exchange airways are made of alveoli, or small microscopic air sacs, that are responsible for the exchange of oxygen and carbon dioxide during normal respiration. Alveoli are composed of two cell types, type I and type II pneumocytes. Type I pneumocytes cover 95% of alveolar surfaces, and are not able to regenerate.
Males also have resonating chambers to increase the volume of sound production. These chambers are pharyngeal air sacs connected to a large sinus in the humped snout. These numerous adaptations caused scientists Herbert Lang and James Chapin to remark, "In no other mammal is everything so entirely subordinated to the organs of voice". Males overall have boxy heads with enormous lips, while the females, with their narrower snouts, have more foxlike faces.
This allows them to penetrate up to below the surface, and they will swim down to an average , sometimes deeper than . The bird's subcutaneous air sacs may have a role in controlling their buoyancy. Gannets usually push their prey deeper into the water and capture it as they return to the surface. When a dive is successful, they swallow the fish underwater before surfacing, and never fly with the fish in their bill.
The vertebral arches were so heavily pierced by extensions of the external air sacs that of their side walls little remained but thick intersecting laminae, the ridges between the pneumatic openings. The vertebrae of the tail, however, did have solid centra. The pelvic and pectoral girdle bones were very thin also, often only several millimetres thick. Like other sauropods, its limbs were robust, contrasting with the extremely lightweight construction of the rest of the skeleton.
Both air sacs contracted simultaneously to pump the used air out of the trachea. This procedure guaranteed a unidirectional airflow, the air always moving in a single forward direction in the lung itself. This significantly improved the oxygen intake and the release of carbon dioxide. Not only was dead air removed quickly but also the blood flow in the lung was counterdirectional in relation to the airflow, leading to a far more effective gas exchange.
In sauropods, the air sacs did not simply function as an aid for respiration; by means of air channels they were connected to much of the skeleton. These branches, the diverticula, via pneumatic openings invaded many bones and strongly hollowed them out. It is not entirely clear what the evolutionary benefit of this phenomenon was but in any case it considerably lightened the skeleton. They might also have removed excess heat to aid thermoregulation.
This 10% include critical areas that require blood flow to remain high to prevent freezing, such as their eyes. Their eyes and ears tend to be the warmest regions. It has been found that temperatures of lower appendages were no more than above ambient temperature, which minimizes heat exchange between feet, toes, wings, and legs. Both the Gular and air sacs, being close to body temperature, are the main contributors to heat and water loss.
Chondrosteosaurus (meaning "cartilage and bone lizard") was a sauropod from Early Cretaceous England. The type species, Chondrosteosaurus gigas, was described and named by Richard Owen in 1876. The fossils of Chondrosteosaurus were discovered in the Wessex Formation on the Isle of Wight. C. gigas is known only from two neck vertebrae (specimens BMNH 46869, the holotype, and BMNH 46870), with distinctive hollows and internal passages now interpreted as evidence of pneumatic air sacs.
The cervical vertebrae are highly pneumatized with very complex internal chambers across the neural arches and the centrum (body of the vertebra), indicating the presence of cervical air sacs. The anterior dorsal and some caudal vertebrae features some degree of pneumacity, however, the sacral vertebrae are apneumatic. In a 2001 study conducted by Bruce Rothschild and other paleontologists, 229 foot bones referred to Archaeornithomimus were examined for signs of stress fracture, but none were found.
He assigned these specimens to the new genus Pelorosaurus, and grouped it together with the dinosaurs. However, Mantell still did not recognize the relationship to Cetiosaurus. The next sauropod find to be described and misidentified as something other than a dinosaur were a set of hip vertebrae described by Harry Seeley in 1870. Seeley found that the vertebrae were very lightly constructed for their size and contained openings for air sacs (pneumatization).
The empty space between the pubic bones and the intestines has by G.S. Paul and David Martill been hypothesised to have been the location of a large air-sac. Dal Sasso & Maganuco however, rejected this interpretation because with living birds the air-sac of the posterior abdomen does not force the intestines forwards. They considered the space more likely to have been filled by a large yolk-sac. Air-sacs were nevertheless probable given the pneumatisation of the vertebrae.
19 The cross-current respiratory gas exchanger in the lungs of birds. Air is forced from the air sacs unidirectionally (from right to left in the diagram) through the parabronchi. The pulmonary capillaries surround the parabronchi in the manner shown (blood flowing from below the parabronchus to above it in the diagram). Blood or air with a high oxygen content is shown in red; oxygen-poor air or blood is shown in various shades of purple-blue.
Ten dorsal ribs are on either side of the body. The large neck was filled with an extensive system of weight-saving air sacs. Brontosaurus, like its close relative Apatosaurus, had tall spines on its vertebrae, which made up more than half the height of the individual bones. The shape of the tail was unusual for diplodocids, being comparatively slender, due to the vertebral spines rapidly decreasing in height the farther they are from the hips.
Some of these potential drugs target the inflammatory response or the specific site(s) of injury. Others modulate the activity of ion channels that control fluid transport across lung membranes or target surfactant, a substance that lines the air sacs in the lungs and prevents them from collapsing. Mechanistic information based on toxicology, biochemistry, and physiology may be instrumental in determining new targets for therapy. Mechanistic studies may also aid in the development of new diagnostic approaches.
The premaxillae on their elongated rostrum have large and slightly convex fossae for the air sacs associated with the presence of a melon, indicating the ability for echolocation. Squalodon and Eosqualodon are based on partial or complete skulls. The synapomorphic traits of the family are, however, based mostly on one of the bones of the inner ear, the periotic bone, which is unknown in these genera except in Squalodon. The monophyly of the family is, therefore, uncertain.
Brachiosaurus also appears to have experienced an elongation of the metacarpals, which in juveniles were shorter compared to the length of the radius; SMA 0009 had a ratio of just 0.33, the lowest known in the entire Neosauropoda. Another plausible ontogenetic change is the increased pneumatization of the vertebrae. During growth, the diverticula of the air sacs invaded the bones and hollowed them out. SMA 0009 already has pleurocoels, pneumatic excavations, at the sides of its neck vertebrae.
The surface temperature of the gular area is ; that of the tracheal area, between ; and that of both anterior and posterior air sacs, . The long trachea, being cooler than body temperature, is a site of water evaporation. As ambient air becomes hotter, additional evaporation can take place lower in the trachea making its way to the posterior sacs, shunting the lung surface. The trachea acts as a buffer for evaporation because of the length, and the controlled vascularization.
The male has distinctive genitalia and a loud and complex call generated by the frequent buckling of ribbed tymbals and amplified by abdominal air sacs. The floury baker is solitary and occurs in low densities. Individuals typically emerge from the soil through a three-month period from late November to late February, and can be encountered until May. The floury baker is found on a wide variety of trees, with some preference for species of paperbark (Melaleuca).
Restoration of a pair of D. macronyx The body structure of Dimorphodon displays many "primitive" characteristics, such as, according to Owen, a very small brain-pan and proportionally short wings. The first phalanx in its flight finger is only slightly longer than its lower arm. The neck was short but strong and flexible and may have had a membranous pouch on the underside. The vertebrae had pneumatic foramina, openings through which the air sacs could reach the hollow interior.
Illustrations of various Istiodactylus bones, including the neck vertebrae and notarium The vertebral column of ornithocheiromorphs was heavily pneumatized by an extensive system of air sacs, leaving prominent pneumatic foraminae. The neck of ornithocheiromorphs was typically relatively long and robust, being longer than the torso in some derived clades. The neural spines of ornithocheiromorph cervical vertebrae were generally tall and spikelike. In some genera such as Tropeognathus and Istiodactylus, up to six dorsal vertebrae are fused into a notarium.
Like the coelophysoids, Tawa has a kink in its upper jaws, between the maxilla and the premaxilla. With respect to limb proportion, the femur is very long compared to the tibia. A neck vertebrae adaptation in Tawa supports the hypothesis that cervical air sacs predate the origin of the Neotheropoda and may be ancestral for saurischians, and also links the dinosaurs with the evolution of birds. Compared to earlier dinosaurs like Herrerasaurus and Eoraptor, Tawa had a relatively slender build.
Locustacarus buchneri is a parasitic mite that lives in the respiratory air sacs of bumblebees. They are relatively host-specific and are found primarily in the subgenus Bombus sensu stricto. Bees infested with the mite have a reduced lifespan in laboratory conditions, and although in one study they foraged at a rate similar to uninfected bees, infected bees showed a greater preference for a single flower type. Prevalence varies, but infection appears to be more common among commercial colonies than wild populations.
Streptococcus pneumoniaeis part of the normal upper respiratory tract flora. As with many natural flora, it can become pathogenic under the right conditions, typically when the immune system of the host is suppressed. Invasins, such as pneumolysin, an antiphagocytic capsule, various adhesins, and immunogenic cell wall components are all major virulence factors. After S. pneumoniae colonizes the air sacs of the lungs, the body responds by stimulating the inflammatory response, causing plasma, blood, and white blood cells to fill the alveoli.
This unorganized network of microscopic tubes branches off from the posterior air sacs, and open haphazardly into both the dorso- and ventrobronchi, as well as directly into the intrapulmonary bronchi. Unlike the parabronchi, in which the air moves unidirectionally, the air flow in the neopulmonic parabronchi is bidirectional. The neopulmonic parabronchi never make up more than 25% of the total gas exchange surface of birds. The syrinx is the sound-producing vocal organ of birds, located at the base of a bird's trachea.
Surface temperature can be affected by the rate of blood flow to a certain area, and also by the surface area of the surrounding tissue. The ostrich reduces blood flow to the trachea to cool itself, and vasodilates its blood vessels around the gular region to raise the temperature of the tissue. The air sacs are poorly vascularized but show an increased temperature, which aids in heat loss. Common ostriches have evolved a 'selective brain cooling' mechanism as a means of thermoregulation.
Posterior dorsal vertebra in rear and side views The dorsal vertebrae of NHMUK R3078 are incomplete or fragmentary. A partial anterior dorsal is known from a single centrum, which is about as long as wide, with a strong anterior articular ball (an opisthocoelous condition). On the lateral surfaces (sides) of the centrum there are deep but small pleurocoels (depressions in the sides of vertebrae for air sacs). A single middle dorsal centrum is preserved, being slightly smaller than the anterior dorsal.
These intermolecular forces put great restraint on the inner walls of the air sac, tighten the surface all together, and unyielding to stretch for inhalation. Thus, without something to alleviate this surface tension, alveoli can collapse and cannot be filled up again. Surfactant is essential mixture that is released into the air-facing surface of inner walls of air sacs to lessen the strength of surface tension. This mixture inserts itself among water molecules and breaks up hydrogen bonds that hold the tension.
Birds also do not have diaphragms or pleural cavities. Bird lungs are smaller than those in mammals of comparable size, but the air sacs account for 15% of the total body volume, compared to the 7% devoted to the alveoli which act as the bellows in mammals. Inhalation and exhalation are brought about by alternately increasing and decreasing the volume of the entire thoraco-abdominal cavity (or coelom) using both their abdominal and costal muscles. During inhalation the muscles attached to the vertebral ribs (Fig.
European honey bee carrying pollen in a pollen basket back to the hive Marmalade hoverfly, pollen on its face and legs, sitting on a rockrose. Diadasia bee straddles flower carpels while visiting yellow Opuntia engelmannii cactus The transfer of pollen grains to the female reproductive structure (pistil in angiosperms) is called pollination. This transfer can be mediated by the wind, in which case the plant is described as anemophilous (literally wind-loving). Anemophilous plants typically produce great quantities of very lightweight pollen grains, sometimes with air-sacs.
As it is only known from isolated vertebrae, little is known about the appearance of Ornithodesmus. The neural spines of the vertebrae are fused and form a blade over the 9.6 centimetres long sacrum, which is slightly arched. The bases of the neural spines form a lateral platform, and the first two vertebrae of the sequence have deep hollow cavities, which formed space for air sacs. Based on its apparent identity as a dromaeosaur, it was probably carnivorous, and likely measured about long in life.
"Postcranial skeletal pneumaticity and air-sacs in the earliest pterosaurs." Biology Letters, 5(4): 557–560. ). Unlike their descendants the pterodactyloids, most rhamphorhynchoids had teeth and long tails, and most species lacked a bony crest, though several are known to have crests formed from soft tissue like keratin. They were generally small, with wingspans rarely exceeding 2.5 meters, though one species alluded to by Alexander Stoyanow might be among the largest pterosaurs of all time with a wingspan of 10 meters, comparable to the largest azhdarchids.
Classification of IIPs. Idiopathic pulmonary fibrosis (IPF) belongs to a large group of more than 200 lung diseases known as interstitial lung diseases (ILDs), which are characterized by the involvement of the lung interstitium, the tissue between the air sacs of the lung. IPF is one specific presentation of idiopathic interstitial pneumonia (IIP), which is in turn a type of ILD, also known as diffuse parenchymal lung disease (DPLD). The 2002 American Thoracic Society/European Respiratory Society (ATS/ERS) classification of IIPs was updated in 2013.
A recent study of the lungs of Alligator mississippiensis (the American alligator) has shown that the airflow through them is unidirectional, moving in the same direction during inhalation and exhalation. This is also seen in birds and many non-avian dinosaurs, which have air sacs to further aid in respiration. Both birds and alligators achieve unidirectional air flow through the presence of parabronchi, which are responsible for gas exchange. The study has found that in alligators, air enters through the second bronchial branch, moves through the parabronchi, and exits through the first bronchial branch.
The respiratory system (also respiratory apparatus, ventilatory system) is a biological system consisting of specific organs and structures used for gas exchange in animals and plants. The anatomy and physiology that make this happen varies greatly, depending on the size of the organism, the environment in which it lives and its evolutionary history. In land animals the respiratory surface is internalized as linings of the lungs. Gas exchange in the lungs occurs in millions of small air sacs called alveoli in mammals and reptiles, but atria in birds.
Vertebrae of the front part of the dorsal column were slightly taller but much longer than those of the back part. This is in contrast to Giraffatitan, where the vertebrae at the front part were much taller but only slightly longer. The centra (vertebral bodies), the lower part of the vertebrae, were more elongated and roughly circular in cross-section, while those of Giraffatitan were broader than tall. The foramina (small openings) on the sides of the centra, which allowed for the intrusion of air sacs, were larger than in Giraffatitan.
Unlike many other hadrosaurids, Edmontosaurus lacked a bony crest. It may have had soft- tissue display structures in the skull, though: the bones around the nasal openings had deep indentations surrounding the openings, and this pair of recesses are postulated to have held inflatable air sacs, perhaps allowing for both visual and auditory signaling. Edmontosaurus may have been dimorphic, with more robust and more lightly built forms, but it has not been established if this is related to sexual dimorphism. Edmontosaurus has been considered a possibly migratory hadrosaurid by some authors.
Air is forced from the air sacs unidirectionally (from right to left in the diagram) through the parabronchi. The pulmonary capillaries surround the parabronchi in the manner shown (blood flowing from below the parabronchus to above it in the diagram). Blood or air with a high oxygen content is shown in red; oxygen-poor air or blood is shown in various shades of purple-blue.The blood flow through the bird lung is at right angles to the flow of air through the parabronchi, forming a cross- current flow exchange system (see illustration on the left).
Serving the purpose of weight-saving, as seen in other sauropods, many of the vertebrae were hollowed out, or "pneumatic"; that is, the vertebrae were riddled with passages and cavities for an intricate system of air sacs connected to the lungs. This feature was little understood at the time Camarasaurus was discovered, but its structure was the inspiration for the creature's name, meaning "chambered lizard". The neck and counterbalancing tail were shorter than usual for a sauropod of this size. Camarasaurus, like certain other sauropods, had an enlargement of the spinal cord near the hips.
The distinctive nasal arch of Gryposaurus, like other cranial modifications in duckbills, may have been used for a variety of social functions, such as identification of sexes or species and social ranking. It could also have functioned as a tool for broadside pushing or butting in social contests, and there may have been inflatable air sacs flanking it for both visual and auditory signaling. The top of the arch is roughened in some specimens, suggesting that it was covered by thick, keratinized skin, or that there was a cartilaginous extension.
Although feathers are light, a bird's plumage weighs two or three times more than its skeleton, since many bones are hollow and contain air sacs. Color patterns serve as camouflage against predators for birds in their habitats, and serve as camouflage for predators looking for a meal. As with fish, the top and bottom colors may be different, in order to provide camouflage during flight. Striking differences in feather patterns and colors are part of the sexual dimorphism of many bird species and are particularly important in selection of mating pairs.
The only sounds that ostriches produce are roars and hisses. The largest air sacs found within the respiratory system are those of the post-thoracic region, while the others decrease in size respectively, the interclavicular (unpaired), abdominal, pre-thoracic, and lateral clavicular sacs. The adult common ostrich lung lacks connective tissue known as interparabronchial septa, which render strength to the non-compliant avian lung in other bird species. Due to this the lack of connective tissue surrounding the parabronchi and adjacent parabronchial lumen, they exchange blood capillaries or avascular epithelial plates.
The oxygen rich air flows unidirectionally across the respiratory surface of the lungs; providing the blood that has a crosscurrent flow with a high concentration of oxygen. To compensate for the large "dead" space, the common ostrich trachea lacks valves to allow faster inspiratory air flow. In addition, the total lung capacity of the respiratory system, (including the lungs and ten air sacs) of a ostrich is about , with a tidal volume ranging from . The tidal volume is seen to double resulting in a 16 fold increase in ventilation.
A pneumothorax (collapsed lung) is an abnormal collection of air in the pleural space that causes an uncoupling of the lung from the chest wall. The lung cannot expand against the air pressure inside the pleural space. An easy to understand example is a traumatic pneumothorax, where air enters the pleural space from outside the body, as occurs with puncture to the chest wall. Similarly, scuba divers ascending while holding their breath with their lungs fully inflated can cause air sacs (alveoli) to burst and leak high pressure air into the pleural space.
Snakes and limbless lizards typically possess only the right lung as a major respiratory organ; the left lung is greatly reduced, or even absent. Amphisbaenians, however, have the opposite arrangement, with a major left lung, and a reduced or absent right lung. Both crocodilians and monitor lizards have developed lungs similar to those of birds, providing a unidirectional airflow and even possessing air sacs. The now extinct pterosaurs have seemingly even further refined this type of lung, extending the airsacs into the wing membranes and, in the case of lonchodectids, tupuxuara, and azhdarchoids, the hindlimbs.
Inflammation, such as that caused by sepsis, causes endothelial cell dysfunction, fluid leakage from capillaries and impairs drainage of fluid from the lungs. Elevated inspired oxygen concentration often becomes necessary at this stage, and may facilitate a 'respiratory burst' in immune cells. In a secondary phase, endothelial cell dysfunction causes cells and inflammatory exudate to enter the alveoli. This pulmonary edema increases the thickness of the layer separating the blood in the capillary from the space in the air sacs, which increases the distance the oxygen must diffuse to reach the blood.
This private channel is used by some rodents in, for example, mother-to-pup communication, and by bats when echolocating. Toothed whales also use echolocation, but, as opposed to the vocal membrane that extends upward from the vocal folds, they have a melon to manipulate sounds. Some mammals, namely the primates, have air sacs attached to the larynx, which may function to lower the resonances or increase the volume of sound. The vocal production system is controlled by the cranial nerve nuclei in the brain, and supplied by the recurrent laryngeal nerve and the superior laryngeal nerve, branches of the vagus nerve.
Scanning electron micrograph of Mycobacterium tuberculosis There is a specific bacterium that evolves inside the body to result in tuberculosis, known as mycobacterium tuberculosis. This bacterium is only spread throughout the body when a person has an active TB infection. One of many causes of acquiring TB is living a life with a weak immune system; everything becomes fragile, and an easy target. That is why babies, children, and senior adults have a higher risk of adapting TB. The bacterium spreads in the air sacs, and passes off into the lungs, resulting in an infected immune system.
The underlying mechanism involves diffuse injury to cells which form the barrier of the microscopic air sacs of the lungs, surfactant dysfunction, activation of the immune system, and dysfunction of the body's regulation of blood clotting. In effect, ARDS impairs the lungs' ability to exchange oxygen and carbon dioxide. Adult diagnosis is based on a PaO2/FiO2 ratio (ratio of partial pressure arterial oxygen and fraction of inspired oxygen) of less than 300 mm Hg despite a positive end-expiratory pressure (PEEP) of more than 5 cm H2O. Heart-related pulmonary edema, as the cause, must be excluded.
These air sacs may have allowed for a basic form of avian-style 'flow-through ventilation,' where air flow through the lungs is one-way, so that oxygen-rich air inhaled from outside the body is never mixed with exhaled air laden with carbon dioxide. This method of respiration, while complicated, is highly efficient. The recognition of pneumatic foramina in Majungasaurus, besides providing an understanding of its respiratory biology, also has larger-scale implications for evolutionary biology. The split between the ceratosaur line, which led to Majungasaurus, and the tetanuran line, to which birds belong, occurred very early in the history of theropods.
Stereo images of the furculae of A. riocoloradense (A) and the Magpie-goose, Anseranas semipalmata (B). Scale bars are 10 cm in (A) and 2 cm in (B). Some of Aerosteon's bones show pneumatisation (air-filled spaces), including pneumatic hollowing of the furcula and ilium, and pneumatisation of several gastralia, suggesting that it may have had a respiratory air-sac system similar to that of modern birds. These air sacs would have acted like bellows, moving air into and out of the animal's relatively inflexible lungs, instead of the lungs themselves being expanded and contracted as occurs with mammals.
Composite image of the fossil caudal (tail) vertebrae The tail of Dreadnoughtus schrani has several characteristic features included in the diagnosis of the species. The first vertebra of the tail has a ridge on its ventral surface called a keel. In the first third of the tail, the bases of the neural spines are extensively subdivided into cavities caused by contact with air sacs (part of the dinosaur's respiratory system). In addition, the anterior and posterior boundaries of these neural spines have distinct ridges (pre- and postspinal laminae) connecting them to the pre- and postzygapophyses (the articulation points of the neural arches).
This process occurs by simple diffusion, across a very thin membrane (known as the blood–air barrier), which forms the walls of the pulmonary alveoli (Fig. 10). It consisting of the alveolar epithelial cells, their basement membranes and the endothelial cells of the alveolar capillaries (Fig. 10). This blood gas barrier is extremely thin (in humans, on average, 2.2 μm thick). It is folded into about 300 million small air sacs called alveoli (each between 75 and 300 µm in diameter) branching off from the respiratory bronchioles in the lungs, thus providing an extremely large surface area (approximately 145 m2) for gas exchange to occur.
During inhalation, environmental air initially enters the bird through the nostrils from where it is heated, humidified, and filtered in the nasal passages and upper parts of the trachea. From there, the air enters the lower trachea and continues to just beyond the syrinx, at which point the trachea branches into two primary bronchi, going to the two lungs. The primary bronchi enter the lungs to become the intrapulmonary bronchi, which give off a set of parallel branches called ventrobronchi and, a little further on, an equivalent set of dorsobronchi. The ends of the intrapulmonary bronchi discharge air into the posterior air sacs at the caudal end of the bird.
The respiratory system had efficient unidirectional "flow-through" breathing using air sacs, which hollowed out their bones to an extreme extent. Pterosaurs spanned a wide range of adult sizes, from the very small anurognathids to the largest known flying creatures of all time, including Quetzalcoatlus and Hatzegopteryx, which reached wingspans of at least nine metres. The combination of endothermy, a good oxygen supply and strong muscles made pterosaurs powerful and capable flyers. Pterosaurs are often referred to by popular media or the general public as "flying dinosaurs", but dinosaurs are defined as the descendants of the last common ancestor of the Saurischia and Ornithischia, which excludes the pterosaurs.
These aerodynamic valves within the bronchial tree have been hypothesised to explain how crocodilians can have unidirectional airflow without the aid of avian-like air sacs. The lungs of crocodilians are attached to the liver and the pelvis by the diaphragmaticus muscle (analogous of the diaphragm in mammals). During inhalation, the external intercostal muscles expand the ribs, allowing the animal to take in more air, while the ischiopubis muscle causes the hips to swing downwards and push the belly outward, and the diaphragmaticus pulls the liver back. When exhaling, the internal intercostal muscles push the ribs inward, while the rectus abdominis pulls the hips and liver forwards and the belly inward.
Asbestosis is the scarring of lung tissue (beginning around terminal bronchioles and alveolar ducts and extending into the alveolar walls) resulting from the inhalation of asbestos fibers. There are two types of fibers: amphibole (thin and straight) and serpentine (curly). All forms of asbestos fibers are responsible for human disease as they are able to penetrate deeply into the lungs. When such fibers reach the alveoli (air sacs) in the lung, where oxygen is transferred into the blood, the foreign bodies (asbestos fibers) cause the activation of the lungs' local immune system and provoke an inflammatory reaction dominated by lung macrophages that respond to chemotactic factors activated by the fibers.
With surgery operations such as popliteal bypass, there will be an increased probability of blood clot formation. In rare cases, a part of the clot in the leg breaks free and travels to the lungs, this is also known as a pulmonary embolism. A blockage in the blood vessels of the lung can be formed by pulmonary embolism, and this could cause excess fluid build-up in the lung. This condition is also known as pulmonary edema, which is the excess fluid present in the lungs, more specifically, the accumulation of excess fluid in the air sacs of the lung, leading to the impairment of gas exchange and potentially respiratory failure.
The pathophysiology of acute respiratory distress syndrome involves fluid accumulation in the lungs not explained by heart failure (noncardiogenic pulmonary edema). It is typically provoked by an acute injury to the lungs that results in flooding of the lungs' microscopic air sacs responsible for the exchange of gases such as oxygen and carbon dioxide with capillaries in the lungs. Additional common findings in ARDS include partial collapse of the lungs (atelectasis) and low levels of oxygen in the blood (hypoxemia). The clinical syndrome is associated with pathological findings including pneumonia, eosinophilic pneumonia, cryptogenic organizing pneumonia, acute fibrinous organizing pneumonia, and diffuse alveolar damage (DAD).
During inhalation air enters the trachea via the nostrils and mouth, and continues to just beyond the syrinx at which point the trachea branches into two primary bronchi, going to the two lungs (Fig. 16). The primary bronchi enter the lungs to become the intrapulmonary bronchi, which give off a set of parallel branches called ventrobronchi and, a little further on, an equivalent set of dorsobronchi (Fig. 16). The ends of the intrapulmonary bronchi discharge air into the posterior air sacs at the caudal end of the bird. Each pair of dorso- ventrobronchi is connected by a large number of parallel microscopic air capillaries (or parabronchi) where gas exchange occurs (Fig. 16).
Life restoration showing hypothetical nasal ornamentation Like all sauropod dinosaurs, Brachiosaurus was a quadruped with a small skull, a long neck, a large trunk with a high-ellipsoid cross section, a long, muscular tail and slender, columnar limbs. Large air sacs connected to the lung system were present in the neck and trunk, invading the vertebrae and ribs by bone resorption, greatly reducing the overall density of the body. The neck is not preserved in the holotype specimen, but was very long even by sauropod standards in the closely related Giraffatitan, consisting of thirteen elongated cervical (neck) vertebrae. The neck was held in a slight S-curve, with the lower and upper sections bent and a straight middle section.
Pneumatopores on the left ilium of Aerosteon riocoloradensis Large meat-eating dinosaurs had a complex system of air sacs similar to those found in modern birds, according to a 2005 investigation led by Patrick M. O'Connor. The lungs of theropod dinosaurs (carnivores that walked on two legs and had bird-like feet) likely pumped air into hollow sacs in their skeletons, as is the case in birds. "What was once formally considered unique to birds was present in some form in the ancestors of birds", O'Connor said. In 2008, scientists described Aerosteon riocoloradensis, the skeleton of which supplies the strongest evidence to date of a dinosaur with a bird-like breathing system.
The tube through which food is ingested and saliva excreted during feeding is formed in most mites by apposing the sheath that contains the chelicerae against the hypostome. However, the trombiculids are an exception. Some species of mites (Analgidae) have adapted to feeding on keratin and skin debris amongst the feathers of birds, and other species have adapted to feed directly on internal tissues such as air-sacs or lungs (Cytoditidae and Laminosioptidae). Psoroptic mites feed superficially at the stratum corneum; the photograph of a histological section of skin infested with Psoroptes ovis, and the photograph of the surface of a host's skin infested with P. ovis looking like white dots, show this type of feeding.
Diagrammatic location of the air sacs of the common ostrich Morphology of the common ostrich lung indicates that the structure conforms to that of the other avian species, but still retains parts of its primitive avian species, ratite, structure. The opening to the respiratory pathway begins with the laryngeal cavity lying posterior to the choanae within the buccal cavity. The tip of the tongue then lies anterior to the choanae, excluding the nasal respiratory pathway from the buccal cavity. The trachea lies ventrally to the cervical vertebrae extending from the larynx to the syrinx, where the trachea enters the thorax, dividing into two primary bronchi, one to each lung, in which they continue directly through to become mesobronchi.
Although heavy ballasting will prevent passive ascent, Beaune et al. surmised that a bird with a mass of 12 kg would need a ballast of at least 1.3 kilograms in pebbles to achieve neutral buoyancy at a depth of 50 meters, potentially making it beneficial for foraging. ;Large air spaces Similar to having light bones, birds also have large respiratory systems with large air spaces that reduce body weight and allow more efficient oxygen exchange required for the high metabolic demands of flight. Birds also have specialized structures called air sacs closely associated with their lungs that store air when the animal inspires, further reducing body weight and maintaining the partial pressure of oxygen within the lungs equal to that of the surrounding environment.
The study suggested that the Antarctic ice sheet may be sensitive to atmospheric carbon dioxide levels that are not far from where they currently reside. Tripati has also applied her expertise in clumped isotope geochemistry towards determining the body temperatures of dinosaurs that have long been extinct. As a visiting professor at California Institute of Technology, she collaborated on a 2011 study that analyzed the composition of fossilized teeth of Jurassic sauropods to find that their internal body temperature was close to that of most modern mammals, resting somewhere between 36 and 38˚C. Scientists had previously hypothesized that sauropod body temperature was warmer, but their study suggested that these dinosaurs stayed cool by using internal air sacs for ventilation.
The lung-on-a-chip places two layers of living tissues—the lining of the lung's air sacs and the blood vessels that surround them—across a porous, flexible boundary. Air is delivered to the lung lining cells, a rich culture medium flows in the capillary channel to mimic blood, and cyclic mechanical stretching is generated by a vacuum applied to the chambers adjacent to the cell culture channels to mimic breathing. The research findings for lung-on-a-chip were published in the June 25, 2010, issue of Science, the academic journal of the American Association for the Advancement of Science. The research was funded by the National Institutes of Health, the American Heart Association, and the Wyss Institute for Biologically Inspired Engineering at Harvard University.
Tail vertebrae of specimen FMNH P25112, showing pneumatic fossae (holes) Given the large body mass and long neck of sauropods like Apatosaurus, physiologists have encountered problems determining how these animals breathed. Beginning with the assumption that, like crocodilians, Apatosaurus did not have a diaphragm, the dead-space volume (the amount of unused air remaining in the mouth, trachea, and air tubes after each breath) has been estimated at about for a specimen. Paladino calculates its tidal volume (the amount of air moved in or out during a single breath) at with an avian respiratory system, if mammalian, and if reptilian. On this basis, its respiratory system would likely have been parabronchi, with multiple pulmonary air sacs as in avian lungs, and a flow-through lung.
Life restoration showing an adult with feathers, based on those known from the related Ornithomimus Gallimimus had 64–66 vertebrae in its spine, fewer than other ornithomimids. The centra (or bodies) of the vertebrae were platycoelous, with a flat front surface and a concave hind surface, except for the first six caudal (tail) vertebra–where the hind surface was also flat–and those at the end of the tail–which were amphiplatyan with both surfaces flat. Many of the centra had foramina (openings which have also been called "pleurocoels"), and were therefore probably pneumatic (with their hollow chambers invaded by air sacs). The neck consisted of 10 cervical vertebrae, which were all long and wide, except for the atlas bone (the first vertebra that connects with the back of the skull).
This would have indicated the presence of septate lungs, ventilated by a hepatic-piston diaphragm, driven by the liver and a Musculus diaphragmaticus, which in the fossil was visibly attached to the pubes. Such a system would be an argument against the idea that birds, whose lungs are ventilated by air-sacs, are coelurosaurian theropods, and an indication theropods were cold-blooded. John Ruben's conclusions have, however, been questioned by some scientists, such as Lawrence Witmer, who claimed the study to be flawed. The 2011 study concluded that due to the fact that the liver had been preserved as a vague halo, representing body fluids that after death might have covered a larger surface than the organs they originated from, its exact dimensions and extent cannot be determined.
BIOLOGY OF REPRODUCTION 56, 1570–1575 (1997)- Determination of Testis Temperature Rhythms and Effects of Constant Light on Testicular Function in the Domestic Fowl (Gallus domesticus) It was once theorized that birds used their air sacs to cool the testes internally, but later studies revealed that birds' testes are able to function at core body temperature. Some mammals which have seasonal breeding cycles keep their testes internal until the breeding season at which point their testes descend and increase in size and become external. 2) Irreversible adaptation to sperm competition. It has been suggested that the ancestor of the boreoeutherian mammals was a small mammal that required very large testes (perhaps rather like those of a hamster) for sperm competition and thus had to place its testes outside the body.
LCLC-RP is generally considered to be an especially aggressive malignancy that metastasizes widely early on in its clinical course. Similar to most other forms of lung carcinoma, LCLC-RP may spread ("metastasize") in three major ways — by local extension and infiltration into surrounding tissues, by lymphatic spread to regional lymph nodes, and through the bloodstream (hematogeneous metastasis) to distant organs and tissues such as the liver, brain, and skeleton. It has been reported recently that LCLC-RP can metastasize locally within the airways ("aerogeneous spread"), an uncommon mechanism of extension wherein tumor cells migrate along the lung walls and septa, but do not destroy air sacs. Previously, this type of metastatic behavior had not been seen in this particular tumor, being traditionally associated almost exclusively with the "pneumonic" form of pulmonary bronchioloalveolar carcinoma.
Like other sauropods, Brachiosaurus was probably homeothermic (maintaining a stable internal temperature) and endothermic (controlling body temperature through internal means) at least while growing, meaning that it could actively control its body temperature ("warm-blooded"), producing the necessary heat through a high basic metabolic rate of its cells. Russel (1989) used Brachiosaurus as an example of a dinosaur for which endothermy is unlikely, because of the combination of great size (leading to overheating) and great caloric needs to fuel endothermy. Sander (2010) found that these calculations were based on incorrect body mass estimates and faulty assumptions on the available cooling surfaces, as the presence of large air sacs was unknown at the time of the study. These inaccuracies resulted in the overestimation of heat production and the underestimation of heat loss.
The partial pressure of oxygen in the parabronchi declines along their lengths as O2 diffuses into the blood. The blood capillaries leaving the exchanger near the entrance of airflow take up more O2 than do the capillaries leaving near the exit end of the parabronchi. When the contents of all capillaries mix, the final partial pressure of oxygen of the mixed pulmonary venous blood is higher than that of the exhaled air, but is nevertheless less than half that of the inhaled air, thus achieving roughly the same systemic arterial blood partial pressure of oxygen as mammals do with their bellows-type lungs. The trachea is an area of dead space: the oxygen-poor air it contains at the end of exhalation is the first air to re-enter the posterior air sacs and lungs.
In 2018, Loredana Macaluso and colleagues pointed out that the hips of therizinosaurs were peculiar because the shaft of the pubic bone was rotated backwards whereas the pubic boot was strongly projected forwards. While the larger gut associated with herbivory was able to push the shaft backwards, they suggested the pubic boot was restrained by ventilatory muscles that were crucial for cuirassal ventilation—breathing with extra air sacs—which shows the importance of this mode of respiration. In a 2019 study of jaw musculature, Ali Nabavizadeh concluded therizinosaurs were mainly orthal feeders—moving their jaws up and down—and raised their jaws isognathously whereby the upper and lower teeth of each side occluded (contacted each other) at once. The origin and insertion sites of their jaw muscles also added strength to their jaw closure.
In 2004, D.M. Henderson noted that, due to their extensive system of air sacs, sauropods would have been buoyant and would not have been able to submerge their torsos completely below the surface of the water; in other words, they would float, and would not have been in danger of lung collapse due to water pressure when swimming. Evidence for swimming in sauropods comes from fossil trackways that have occasionally been found to preserve only the forefeet (manus) impressions. Henderson showed that such trackways can be explained by sauropods with long forelimbs (such as macronarians) floating in relatively shallow water deep enough to keep the shorter hind legs free of the bottom, and using the front limbs to punt forward. However, due to their body proportions, floating sauropods would also have been very unstable and maladapted for extended periods in the water.
When the contents of all capillaries mix, the final partial pressure of oxygen of the mixed pulmonary venous blood is higher than that of the exhaled air, but is nevertheless less than half that of the inhaled air, thus achieving roughly the same systemic arterial blood partial pressure of oxygen as mammals do with their bellows-type lungs. The trachea is an area of dead space: the oxygen- poor air it contains at the end of exhalation is the first air to re-enter the posterior air sacs and lungs. In comparison to the mammalian respiratory tract, the dead space volume in a bird is, on average, 4.5 times greater than it is in mammals of the same size. Birds with long necks will inevitably have long tracheae, and must therefore take deeper breaths than mammals do to make allowances for their greater dead space volumes.
The ribs were connected to the dorsal (trunk) vertebrae with two joints, acting together as a simple hinge joint, which has allowed researchers to reconstruct the inhaled and exhaled positions of the ribcage. The difference in volume between these two positions defines the air exchange volume (the amount of air moved with each breath), determined to be approximately 20 L for a P. engelhardti individual estimated to have weighed 690 kg, or 29 mL/kg bodyweight. This is a typical value for birds, but not for mammals, and indicates that Plateosaurus probably had an avian-style flow-through lung, although indicators for postcranial pneumaticity (air sacs of the lung invading the bones to reduce weight) can be found on the bones of only a few individuals, and were only recognised in 2010. Combined with evidence from bone histology this indicates that Plateosaurus was endothermic.
One of his more recent innovations is the creation of tiny, complex, three-dimensional models of living human organs, known as "organs-on- chips" (Organ Chips), which mimic complicated human organ functions in vitro as a way to potentially replace traditional animal-based methods for testing of drugs and toxins. The first human Organ Chip, a human Lung Chip, was reported in Science in 2010. Created using microchip manufacturing methods, the Lung Chip is a complex three-dimensional model of a breathing lung that incorporates living human lung alveolar epithelial cells interfaced with endothelial cells within microfluidic channels cast in silicone rubber, which recapitulate structure and function of the tissue-vasculature interface of lung alveolus (air sacs). In 2012, Ingber and his team demonstrated in a study in Science Translational Medicine the ability to mimic a complex human disease on the Lung Chip — specifically pulmonary edema, known commonly as “fluid on the lungs” — and to identify new therapeutics using this model.

No results under this filter, show 236 sentences.

Copyright © 2024 RandomSentenceGen.com All rights reserved.