A scanning electron microscopic study of the air and blood capillaries of the lung of the domestic fowl (Gallus domesticus)

Maina, JN

doi:10.1007/bf02327080

Cited by 41 publications

(42 citation statements)

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“…The existence of a crosscurrent arrangement of the structural components has been reported previously by Duncker (1971Duncker ( , 1974Duncker ( , 1979, Abdalla and King (1975), West et al (1977), Maina (1982Maina ( , 1988, and (Abdalla, 1989). But, while these studies were meticulously done, the techniques that were applied were not sufficiently robust to categorically explicate the highly complex spatial architecture of the exchange tissue of the avian lung.…”

Section: Introductionsupporting

confidence: 71%

“…Study of histological sections, as performed by Abdalla and King (1975), does not allow direct rendition to the three-dimensional (3D) arrangement: the 3D schemes that are developed pursuant to such studies depend largely on the intuition and judgment of the investigator and may be subject to personal bias. Regarding the casting method that was used by West et al (1977), Maina (1982Maina ( , 1988, and Nasu (2005), the accuracy depends on the suitability and the nature of the material used for injection in relation to the size of the structures that are cast. Artifacts may arise from underfilling, overfilling, or in extreme cases extravasation of the material, after failure of the wall of the conduit (Murakami, 1971;Clark et al, 1979;Ohtani, 1980;Lametschwandtner et al, 1984).…”

Section: Introductionmentioning

confidence: 99%

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Three‐Dimensional Serial Section Computer Reconstruction of the Arrangement of the Structural Components of the Parabronchus of the Ostrich, Struthio Camelus Lung

Maina

Woodward

2009

The Anatomical Record

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The Ostrich, Struthio camelus is the largest extant bird. The arrangement of the airway and the vascular components of the parabronchus of its lung were investigated by 3D serial section reconstruction. Modestly developed atrial muscles, shallow atria, paucity of infundibulae with preponderant origination of the air capillaries (ACs) from the atria and lack of interparabronchial septa, structural features that epitomize lungs of most highly derived metabolically active volant birds were observed. Intertwined very closely, the ACs and the blood capillaries (BCs) are not straight, blindended tubules that run in contact, counter and parallel to each other as has been claimed and/or modeled. Crosscurrent (perpendicular ¼ orthogonal) orientation between the centripetal (inward) flow of the venous blood (VB) from the periphery of the parabronchus and the flow of air in the parabronchial lumen occur. Also, a countercurrent-like arrangement between the ACs which convey air centrifugally (outwards ¼ radially) and the BCs that transport venous blood centripetally (inwards) was identified. The VB is conveyed to the parabronchus by the interparabronchial arteries and delivered to the exchange tissue by the intraparabronchial arterioles: it is then arterialized at the infinitely many points where the ACs and the BCs contact. Functionally, the crosscurrent arrangement grants a multicapillary serial arterialization arrangement which extends the time that the respiratory media, air and blood, are exposed to each other. The contribution that the countercurrent-like arrangement makes to the gas exchange process remains obscure.

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Section: Introductionsupporting

confidence: 71%

Section: Introductionmentioning

confidence: 99%

Three‐Dimensional Serial Section Computer Reconstruction of the Arrangement of the Structural Components of the Parabronchus of the Ostrich, Struthio Camelus Lung

Maina

Woodward

2009

The Anatomical Record

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“…The resin casts of the blood vessel in the pigeon [16] and chicken [3,9,10 ] lungs were observed by SEM, and the fine structures of these vascular capillary systems in the gasexchange tissues were demonstrated. West et al [15,16] presented the schematic diagram of the relationship between the blood capillaries and infundibula in the pigeon lung.…”

Section: Double Resin Cast Of the Respiratory And Vascular Systemsmentioning

confidence: 99%

“…However, they could not elucidate the relationship between the vascular capillaries and air capillaries by using the single injection method. The double (of both the vascular and respiratory tracts) injection casting method was applied to chicken lungs [9,10] in order to study the relationship between the air passages and vasculature. However, in these studies, latex rubber was used as the injection medium, and the injection technique is difficult because the artifacts are bound to arise from the extravasates as a result of the excessive pressure [10].…”

Section: Double Resin Cast Of the Respiratory And Vascular Systemsmentioning

confidence: 99%

“…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.…”

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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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Scanning electron microscope study of the spatial organization of the air and blood conducting components of the avian lung (Gallus Gallus variant domesticus)

Maina

1988

Anat. Rec.

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The lungs of the domestic fowl were prepared for scanning electron microscopy after vascular and airway latex rubber casting to demonstrate the spatial organization of the various structural components that are involved in the gas exchange that takes place in the parabronchial tissue mantle. The bulk of the intrapulmonary air flows through the parabronchial lumen and then centrifugally diffuses into the exchange tissue through the atria, the infundibula, and the air capillaries. The blood flows centripetally from the interparabronchial arteries, then into the intraparabronchial arterioles, and finally into the blood capillaries, which together with the air capillaries constitute the functional terminal gas exchange units. The relationship between the air flow in the parabronchial lumen and the incoming blood (into the exchange tissue) has been shown to be crosscurrent, where the directions of the flow of these two gas exchange media are essentially perpendicularly disposed to each other; whereas the relationship between the blood capillaries and the air capillaries is countercurrent, the blood flowing towards the parabronchial lumen and the air in the opposite direction, i.e., towards its periphery. Both these spatial structural relationships between the air and blood are significant factors that contribute to the remarkable efficiency of the avian lung in gas exchange.(ABSTRACT TRUNCATED AT 250 WORDS)

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A scanning electron microscopic study of the air and blood capillaries of the lung of the domestic fowl (Gallus domesticus)

Abstract: Air and blood capillaries of the lung of the domestic fowl constitute the functional gas exchange units. They anastomose profusely and interlace with each other in 3 dimensions. Air capillaries are not blind-ending tubules as has occasionally been suggested.

Cited by 41 publications

References 9 publications

Three‐Dimensional Serial Section Computer Reconstruction of the Arrangement of the Structural Components of the Parabronchus of the Ostrich, Struthio Camelus Lung

Three‐Dimensional Serial Section Computer Reconstruction of the Arrangement of the Structural Components of the Parabronchus of the Ostrich, Struthio Camelus Lung

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

Scanning electron microscope study of the spatial organization of the air and blood conducting components of the avian lung (Gallus Gallus variant domesticus)

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