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P. Speiser 《Journal of Ornithology》1909,57(1):100-104
Ohne Zusammenfassungüber seinen am 3. Oktober in Danzig gehaltenen Vortrag. 相似文献
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Hans-Rainer Duncker 《Journal of Ornithology》2000,141(1):1-67
Zusammenfassung Zum Verständnis der besonderen Struktur- und Funktionsprinzipien des Atemapparates der Vögel werden die spezielle Bauweise des Vogelrumpfes und die bei den Vögeln hochdifferenzierte Septierung ihrer Leibeshöhle dargestellt. Sodann werden der Bau der Lungen und ihres Bronchialsystems beschrieben sowie die Lage und Verbindungen der Luftsäcke und ihrer Divertikel. Die Schilderung der Atembewegungen des Vogelrumpfes ergibt die Grundlage für die Diskussion der Ventilation der Vogellunge. Auf die Darstellung des Aufbaus der Parabronchien, der funktionellen Baueinheit für den Gasaustausch in der Vogellunge, sowie ihres Gefäßsystems folgen die Daten über den quantitativen Aufbau des Lungen-Luftsacksystems von Kolibris bis zu Schwänen und ihrer morphometrisch bestimmten Austauschkapazitäten. Anschließend werden die physiologischen Daten über den Gasaustausch in der Vogellunge und den Transport der Atemgase durch das Blut diskutiert und die Kenntnisse über die sensorische und neuronale Steuerung von Atmung und Gasaustausch aufgeführt. Sodann werden die vorhandenen Daten über den qualitativen und quantitativen Aufbau der Flugmuskulatur und des Herz-Kreislaufsystems zusammengestellt und ihre körpergrößenabhängigen Beziehungen und deren funktionelle Konsequenzen diskutiert. Abschließend wird die Evolution der Vögel als hochentwickelter Warmblüter diskutiert, die mit ihren zu Dauerleistung befähigten Schlagfliegern wie vielen Zugvögeln extrem gesteigerte metabolische und lokomotorische Leistungen vollbringen, von denen sich die als Bodenvögel spezialisierten größeren Hühnervögel mit ihrer sehr beschränkten physiologischen Leistungsfähigkeit aber deutlich unterscheiden.
The respiratory apparatus of birds and their locomotory and metabolic efficiency
Summary The structural and functional principles of the avian respiratory apparatus and the differences with respect to the respiratory apparatus of mammals have been well understood from published investigations since 1970 (for review articles see Duncker 1971, 1978a, 1979, 1983, Fedde 1986, Seller 1987, King & McLelland 1989). The various and great structural and functional differences between birds and mammals are often ignored or have only rarely found adequate treatment. In the face of the fundamental structural uniformity of birds, the large differences which exist in the functional efficiency of their respiratory and cardiovascular apparatus are not generally realized. This applies to an even greater extent to their interaction and cooperation with the locomotory apparatus, especially when comparing the well-known domestic fowl with the more rarely examined wild and migratory birds. Migratory birds are vertebrates whose respiratory, cardiovascular und locomotory apparatus are capable of the highest sustainable effort. In contrast, the physiology of larger fowl-like birds is not designed for the purpose of hard and sustained exercise, but in accordance with their anaerobically performed short escape flight, the capacity of their cardiovascular and respiratory systems is greatly reduced. Fowl-like birds are therefore suitable only to a very limited extent to afford a functional understanding of avian construction. With this in mind the present article reviews the structure of the respiratory apparatus of birds with its important qualitative and quantitative structural and functional characteristics and the functionally important and correlated aspects of the cardiovascular and locomotory systems. Against this background these avian systems are compared with the functional characteristics of the corresponding mammalian systems.The lung air sac system of birds is related to the special construction of the avian trunk and the highly differentiated septation of the body cavity of birds (Fig. 1; Duncker 1971, 1979). The construction of the trunk wall and the septation of the body cavity are responsible for the volume constancy of the pleural cavity during all respiratory movements, thus establishing the necessary structural conditions for the development of the rigid parabronchial lung. Only under these conditions can the parabronchial air capillaries remain extended and air-filled. The ventilation of this rigid avian lung is achieved by the volume changes of the air sacs, whereby the air flow through the parabronchi is directed aerodynamically. The relative rigidity of the avian trunk with its highly specialized articulations between the spinal column, which is more or less immobile, and the ribs and the sternum enables large excursions for the breathing movements so that ventilation of the air sacs can occur with a large amplitude and at minimum pressure differences. By virtue of the large volume elasticity (compliance) of the air sacs the respiratory apparatus of birds works as a low-pressure system. In addition, owing to the special construction of the shoulder girdle of birds as well as to the arrangement of the large flight muscles and the air sac diverticula between the cranial shoulder girdle and the frontal thorax, complete dissociation of respiratory and flight movements can result, which allows birds to fly and to breath with different, even changing frequencies, which are related specifically to body size (Fig. 5; Berger & Hart 1974).In contrast to this avian construction, the mammalian trunk, especially in small to mediumsized mammals, possesses a strongly elastic thorax and a highly pliant lumbar vertebral column, which result in a coupling between locomotory and respiratory movements. The thoracic cage and the cervical and thoracic vertebral column represent the crucial origins for the musculature of the shoulder girdle including its highly mobile scapula. The extensive movements of the lumbar vertebral column are substantial for the locomotory movements of the hind limb. Owing to its small volume elasticity (compliance) and powerful retractile forces, the broncho-alveolar mammalian lung requires larger pressure gradients for full inspiration. Thus, the thorax musculature and a muscularized diaphragm are well developed. In addition to the performance of its inspiratory movements, the diaphragm must also counteract the high intraabdominal pressures, which are an inevitable consequence of the extensive movements of the lumbar vertebral column and the active abdominal muscles, especially during rapid locomotion. Thus, the body cavities of mammals including the pleural cavity are high-pressure systems, which have multiple, not yet investigated effects on the structure and function of different organ systems.Just as the structure and function of the lung air sac apparatus of birds differ fundamentally from the lungs of mammals, the ontogenetic development of the respiratory apparatuses of these two classes are also basically different. In viviparous mammals the lung develops similarly to all lungs of amniotes secreting pulmonary fluid, which fills the lumina of the developing bronchial tree including its respiratory portion. With the onset of respiratory movements in the late embryological/fetal development, this pulmonary fluid comes into partial exchange with the amniotic fluid. During parturition, a portion of the pulmonary fluid is squeezed out by the compression of the fetus. The remaining pulmonary fluid, which is sucked into the terminal ends of the respiratory bronchial tree by the first breath, will be resorbed in the first few hours of life by active transport of the alveolar epithelium and the endothelium of the alveolar capillaries. Thus, the mammalian lung, which has developed a thin exchange surface in the sacculi or alveoli of the respiratory bronchial tree, can aerate most of the exchange surface with the first breath at birth so that it can instantly take over the function of gas exchange from the placenta (Duncker 1990).The avian lung and its principal air sacs develop in the embryo, which is emersed in the amniotic fluid of the egg. Similarly, the lumina of the growing bronchial system are filled with pulmonary fluid. Towards the end of the incubation period the air capillaries start to sprout from the tubuli of the fluid-filled anlagen of the parabronchi between the surrounding blood capillaries. One to three days before hatching, after having swallowed the remaining amniotic fluid, and initiated regular breathing movements, the chick perforates the membrane into the air chamber of the egg (Duncker 1978b, Piiper 1978). Thus, not only the primary and secondary bronchi of the lung and the large air sacs are ventilated, but also the lumina of the parabronchi. The parabronchial air capillaries, which continue growing and sprouting, are filled with pulmonary fluid, which is now absorbed by the epithelium of the air capillaries and the endothelium of the blood capillaries. Depending upon the size of the egg and the duration of the incubation, the air capillaries are completely air-filled after one to two days. With this ventilation and the increasing filling of the air capillaries with air, they progressively assume the gas exchange function, which up to this time has been carried out by the chorioallantoic membrane. The latter is closely attached to the inside of the shell membrane. At the end of this process the embryo hatches. As early as in the embryological development the pleural cavities maintain volume constancy during all respiratory and body movements. The rigid lungs, which grow together with the pleural cavity walls during their embryological development, attain their gas exchange ability after ventilation of the bronchial system only through the resorption of the pulmonary fluid by the epithelium of the air capillaries. The avian lung therefore can only attain its functional capacity for gas exchange by a temporal overlapping of gas exchange by the chorioallantoic membrane with the respiration of air by the lung, which is only possible in a hard-shelled egg. Thus, the highly differentiated, non-inflatable lung structure in birds is inevitably bound to development in a hard-shelled egg (Duncker 1978b).All birds possess a respiratory apparatus that in principle is comparably constructed. They differ vastly, however, in the extent to which the diffusion capacity of their lungs is developed and thus in their metabolic and locomotory efficiency. Those capable of sustained, efficient flight, e.g. hummingbirds to large migratory birds, possess lungs with an exchange capacity that is higher than that of comparably large mammals by a factor of 6 to 8 (Fig. 27). The relative weight of the heart of birds and their cardio-vascular transport capacity are correspondingly larger than in comparable mammals and they have a somewhat larger relative blood volume (Duncker & Güntert 1985). By virtue of this construction, sustainably flying birds can supply their flight musculature, which consists to a large extent or completely of aerobic muscle fibers, which are sufficient for a continuous flapping type flight activity. However, a crucial body-size relationship arises within these functional interdependencies, since the hearts of larger animals can only pump a relatively smaller blood volume per time unit owing to the size-dependent maximum pulse rate. Accordingly, large ducks, geese and swans adapt to these scale problems by a reduction in their relative flight muscle mass, which entailes them using a longer time for take-off with violent flapping of their wings (Fig. 28). Large water birds can perform such a long take-off only on water, out of reach of preying terrestrial hunters.Large land birds, like the large fowl-like birds, owe their survival to the fact that they can save themselves from stalking hunters by a direct lifting flight, in order to escape into a tree or by sweeping off to a safe distance. For a direct lifting flight, however, a flight muscle mass of at least 20% of their total body weight is necessary. Larger sustainably flying birds had to reduce their aerobic, red flight musculature to 13–12% of their total body mass in accordance with the described body-size dependent cardio-vascular blood transport capacity. Based on these scaling interdependencies, the medium- to large-sized fowl-like birds could not differentiate aerobic fibers in their flight musculature. Because of the requirement that flight musculature must amount to 20% of body weight for lifting stroke flight, they were able to differentiate their flight muscles only as anaerobic, white fibers and thus they can fly strongly but fatigue very quickly (Fig. 28). Accordingly, the heart and circulatory system has also differentiated to the physiological needs of the flight musculature. Thus, the size of the heart and the cardio-vascular transport capacity of larger fowl-like birds are reduced to half of or less than the heart size and transport capacity of comparably large sustainably flying birds, and they possess an even more greatly reduced diffusion capacity of their lungs. Medium-sized and large fowl-like birds passed up the development of the ability for sustainable higher metabolic permormance during their very special evolution towards a more terrestrially based, running bird with short escape flight. The fowl-like birds, adapted very well to their specific habitat, therefore are not an appropiate example of a typical bird with the ability for long-term, flapping flight and high metabolic achievement.相似文献
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