Structure of avian lungs

Duncker, Hans-Rainer

doi:10.1016/0034-5687(72)90016-3

Cited by 175 publications

(129 citation statements)

References 12 publications

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“…West et al (2007a) and Watson et al (2008) observed that 'the avian pulmonary BCs behave like rigid tubes that defy either expansion or compression'. Although lined by a less efficient surfactant with paucity of palmitoylmyristoylphosphatidylcholine and one lacking surfactant proteins (SP)-A and SP-C (Bernhard et al 2001), the surface tension prevailing at the air-water interface of the ACs that range in diameter from 3 to 20 lm (Duncker, 1972;Maina & Nathaniel, 2001;Woodward & Maina, 2008) should in all likelihood, as opined by Scheuermann et al (1997) and Watson et al (2008), be much greater than that in an alveolus of equivalent diameter. That even under such conditions the ACs are not only stable but also very strong is most perplexing.…”

Section: Introductionmentioning

confidence: 99%

Implicit mechanistic role of the collagen, smooth muscle, and elastic tissue components in strengthening the air and blood capillaries of the avian lung

2010

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To identify the forces that may exist in the parabronchus of the avian lung and that which may explain the reported strengths of the terminal respiratory units, the air capillaries and the blood capillaries, the arrangement of the parabronchial collagen fibers (CF) of the lung of the domestic fowl, Gallus gallus variant domesticus was investigated by discriminatory staining, selective alkali digestion, and vascular casting followed by alkali digestion. On the luminal circumference, the atrial and the infundibular CF are directly connected to the smooth muscle fibers and the elastic tissue fibers. The CF in this part of the parabronchus form the internal column (the axial scaffold), whereas the CF in the interparabronchial septa and those associated with the walls of the interparabronchial blood vessels form the external, i.e. the peripheral, parabronchial CF scaffold. Thin CF penetrate the exchange tissue directly from the interparabronchial septa and indirectly by accompanying the intraparabronchial blood vessels. Forming a dense network that supports the air and blood capillaries, the CF weave through the exchange tissue. The exchange tissue, specifically the air and blood capillaries, is effectively suspended between CF pillars by an intricate system of thin CF, elastic and smooth muscle fibers. The CF course through the basement membranes of the walls of the blood and air capillaries. Based on the architecture of the smooth muscle fibers, the CF, the elastic muscle fibers, and structures like the interparabronchial septa and their associated blood vessels, it is envisaged that dynamic tensional, resistive, and compressive forces exist in the parabronchus, forming a tensegrity (tension integrity) system that gives the lung rigidity while strengthening the air and blood capillaries.

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Section: Introductionmentioning

confidence: 99%

Implicit mechanistic role of the collagen, smooth muscle, and elastic tissue components in strengthening the air and blood capillaries of the avian lung

2010

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“…Although the qualitative characteristics of the anatomy of the avian lung have been progressively elucidated during the past 100 years (King, 1966;Duncker, 1971), quantitative (stereological) observations have been relatively few (Duncker, 1972(Duncker, . 1973Abdalla.…”

Section: Introductionmentioning

confidence: 99%

Quantitative comparisons of lung structure of adult domestic fowl and red jungle fowl, with reference to broiler ascites

Vidyadaran¹,

King

Kassim³

1990

Avian Pathology

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“…The patterns of arterial supply and respiratory ducts in the pigeon lung are the same as those of other birds [1,2,6,16]. The trachea divides into two primary bronchi, and these primary bronchi ramify into many secondary bronchi that further branch into parabronchi (tertiary bronchi) [4,5,8].…”

Section: Double Resin Cast Of the Respiratory And Vascular Systemsmentioning

confidence: 97%

Scanning Electron Microscopic Study on the Microarchitecture of the Vascular System in the Pigeon Lung

Nasu

2005

The Journal of Veterinary Medical Science

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ABSTRACT. The resin casts of the respiratory and vascular systems in pigeon lung were examined using a scanning electron microscope. The primary bronchi branched to form many secondary bronchi that anastomosed with each other via the parabronchi. Numerous infundibula protruded from the parabronchi via the atria and ramified into the air capillaries. The pulmonary artery entered into the lung and branched into three vessels that coursed the interparabronchial parts. The intraparabronchial arterioles penetrated the gas-exchange tissue to form the anastomosing networks of blood capillaries. The observation of the double casts of the respiratory and vascular systems revealed three-dimensional complicated networks of air capillaries and blood capillaries. KEY WORDS: lung, pigeon, vascular system. J. Vet. Med. Sci. 67(10): 1071-1074, 2005 The respiratory organs of birds are structurally different from those of mammals. The avian lung is devoid of lobulation, alveoli, and tree-like branching of the air ducts that terminate in alveoli [8]. Hence, it can be assumed that the mechanics of breathing of birds are quite different from those of mammals [4].The respiratory system of the avian lung is composed of ramifying and anastomotic parabronchi (tertiary bronchi) [5]. These parabronchi that arise from the secondary bronchi occupy more than half of the avian lung volume in the form of dense bundles of interanastomosing tubes [8]. Some narrow columnar chambers (infundibula) protrude from the parabronchi via the dilated chamber or depression of parabronchial wall known as atria [15], and a number of air capillaries arise from the end of the infundibula [3,5,8,16].Based on the relationship between the direction of air flow and the direction of capillary blood flow within the alveolar walls, two systems for gas exchange in the avian lung have been theorized. These theories, namely, the counter (parallel) current system and the cross current system, are based on the anatomical and physical models as well as gas analysis [3,14,16].The anatomical relationship between the air capillaries and blood capillaries in the chicken lung is studied by the examination of an injected cast by using scanning electron microscope (SEM) [3,9,10] and transmission electron microscope [7]. However, the detailed morphological relationships between the terminal parts of these capillaries have not been verified. The cast of the blood capillary system in the pigeon lung is studied by the SEM in detail [15] but the respiratory system is not described. In this study, the fine structure of the double resin casts of both the respiratory tract and blood vessels in the pigeon lung was observed using SEM in order to elucidate the structural relationship between them at the level of the terminal parts of air capillaries and blood capillaries.All procedures were done in accordance with the "Guiding principles for the care and use of animals in the field of physiological sciences" of the Physiological Society of Japan. A total of 15 adult male pigeons were used in...

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Structure of avian lungs

Cited by 175 publications

References 12 publications

Implicit mechanistic role of the collagen, smooth muscle, and elastic tissue components in strengthening the air and blood capillaries of the avian lung

Implicit mechanistic role of the collagen, smooth muscle, and elastic tissue components in strengthening the air and blood capillaries of the avian lung

Quantitative comparisons of lung structure of adult domestic fowl and red jungle fowl, with reference to broiler ascites

Scanning Electron Microscopic Study on the Microarchitecture of the Vascular System in the Pigeon Lung

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