Comparative Pulmonary Morphology and Morphometry: The Functional Design of Respiratory Systems

Maina, John N.

doi:10.1007/978-3-642-78598-6_4

Cited by 16 publications

(10 citation statements)

References 479 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Among the data available on the bird lungs, the mass-specific V (PCB) of the lung of the Andean goose (7.44 cm 3 .kg -1 ) is only surpassed by that of the diving Humboldti penguin (8.02 cm 3 .kg -1 ) [60] (Table 2). The ratio of the V (PCB) to the total respiratory surface (SA), i.e., V (PCB) .S (t) -1 , the so-called capillary loading [70], indicates the degree of exposure of pulmonary capillary blood to air [65, 70], with low values indicating high gas exchange efficiency. In the avian lungs that have been investigated, V (PCB) .S (t) -1 ranges from 0.7 cm 3 .m -2 in the African rock martin [33, 36, 37, 39, 54] to 4.4 cm 3 .m -2 in the Humboldt penguin [55].…”

Section: Discussionmentioning

confidence: 99%

Morphological and morphometric specializations of the lung of the Andean goose, Chloephaga melanoptera: A lifelong high-altitude resident

et al. 2017

View full text Add to dashboard Cite

High altitude flight in rarefied, extremely cold and hypoxic air is a very challenging activity. Only a few species of birds can achieve it. Hitherto, the structure of the lungs of such birds has not been studied. This is because of the rarity of such species and the challenges of preparing well-fixed lung tissue. Here, it was posited that in addition to the now proven physiological adaptations, high altitude flying birds will also have acquired pulmonary structural adaptations that enable them to obtain the large amounts of oxygen (O2) needed for flight at high elevation, an environment where O2 levels are very low. The Andean goose (Chloephaga melanoptera) normally resides at altitudes above 3000 meters and flies to elevations as high as 6000 meters where O2 becomes limiting. In this study, its lung was morphologically- and morphometrically investigated. It was found that structurally the lungs are exceptionally specialized for gas exchange. Atypically, the infundibulae are well-vascularized. The mass-specific volume of the lung (42.8 cm3.kg-1), the mass-specific respiratory surface area of the blood-gas (tissue) barrier (96.5 cm2.g-1) and the mass-specific volume of the pulmonary capillary blood (7.44 cm3.kg-1) were some of the highest values so far reported in birds. The pulmonary structural specializations have generated a mass-specific total (overall) pulmonary morphometric diffusing capacity of the lung for oxygen (DLo2) of 0.119 mlO2.sec-1.mbar-1.kg-1, a value that is among some of the highest ones in birds that have been studied. The adaptations of the lung of the Andean goose possibly produce the high O2 conductance needed to live and fly at high altitude.

show abstract

Section: Discussionmentioning

confidence: 99%

Morphological and morphometric specializations of the lung of the Andean goose, Chloephaga melanoptera: A lifelong high-altitude resident

et al. 2017

View full text Add to dashboard Cite

show abstract

“…Avian lung structure has been reviewed extensively (184, 185, 186, 374, 375, 465, 475, 476, 481, 482, 485, 526, 566). On its dorsolateral aspect, the lung is deeply marked by the vertebrae and ribs (Fig.…”

Section: Section 4 Avian Respiratory System: Transition From Land Tomentioning

confidence: 99%

Evolution of Air Breathing: Oxygen Homeostasis and the Transitions from Water to Land and Sky

Hsia

Schmitz

Lambertz

et al. 2013

Comprehensive Physiology

278

147

View full text Add to dashboard Cite

Life originated in anoxia, but many organisms came to depend upon oxygen for survival, independently evolving diverse respiratory systems for acquiring oxygen from the environment. Ambient oxygen tension (PO2) fluctuated through the ages in correlation with biodiversity and body size, enabling organisms to migrate from water to land and air and sometimes in the opposite direction. Habitat expansion compels the use of different gas exchangers, for example, skin, gills, tracheae, lungs, and their intermediate stages, that may coexist within the same species; coexistence may be temporally disjunct (e.g., larval gills vs. adult lungs) or simultaneous (e.g., skin, gills, and lungs in some salamanders). Disparate systems exhibit similar directions of adaptation: toward larger diffusion interfaces, thinner barriers, finer dynamic regulation, and reduced cost of breathing. Efficient respiratory gas exchange, coupled to downstream convective and diffusive resistances, comprise the “oxygen cascade”—step-down of PO2 that balances supply against toxicity. Here, we review the origin of oxygen homeostasis, a primal selection factor for all respiratory systems, which in turn function as gatekeepers of the cascade. Within an organism's lifespan, the respiratory apparatus adapts in various ways to upregulate oxygen uptake in hypoxia and restrict uptake in hyperoxia. In an evolutionary context, certain species also become adapted to environmental conditions or habitual organismic demands. We, therefore, survey the comparative anatomy and physiology of respiratory systems from invertebrates to vertebrates, water to air breathers, and terrestrial to aerial inhabitants. Through the evolutionary directions and variety of gas exchangers, their shared features and individual compromises may be appreciated.

show abstract

“…Abdalla & King, 1975 ;Scheid & Piiper, 1972 ;West et al, 1977;Maina, 1988), the arrangement between the bulk air flow in the parabronchial lumen and the flow of deoxygenated blood into the blood capillaries (from the interparabronchial arteries via the intraparabronchial arterioles) is essentially perpendicular (Fig. A from Maina (2002 b); B from Maina (1994) ; C-E from Maina (1988). Flowing centripetally (i.e.…”

Section: Assemblage Of the Airway And Vascular Conduitsmentioning

confidence: 99%

Development, structure, and function of a novel respiratory organ, the lung-air sac system of birds: to go where no other vertebrate has gone

Maina¹

2007

Biological Reviews

116

View full text Add to dashboard Cite

Among the air-breathing vertebrates, the avian respiratory apparatus, the lung-air sac system, is the most structurally complex and functionally efficient. After intricate morphogenesis, elaborate pulmonary vascular and airway (bronchial) architectures are formed. The crosscurrent, countercurrent, and multicapillary serial arterialization systems represent outstanding operational designs. The arrangement between the conduits of air and blood allows the respiratory media to be transported optimally in adequate measures and rates and to be exposed to each other over an extensive respiratory surface while separated by an extremely thin blood-gas barrier. As a consequence, the diffusing capacity (conductance) of the avian lung for oxygen is remarkably efficient. The foremost adaptive refinements are : (1) rigidity of the lung which allows intense subdivision of the exchange tissue (parenchyma) leading to formation of very small terminal respiratory units and consequently a vast respiratory surface ; (2) a thin blood-gas barrier enabled by confinement of the pneumocytes (especially the type II cells) and the connective tissue elements to the atria and infundibulae, i.e. away from the respiratory surface of the air capillaries ; (3) physical separation (uncoupling) of the lung (the gas exchanger) from the air sacs (the mechanical ventilators), permitting continuous and unidirectional ventilation of the lung. Among others, these features have created an incredibly efficient gas exchanger that supports the highly aerobic lifestyles and great metabolic capacities characteristic of birds. Interestingly, despite remarkable morphological heterogeneity in the gas exchangers of extant vertebrates at maturity, the processes involved in their formation and development are very similar. Transformation of one lung type to another is clearly conceivable, especially at lower levels of specialization. The crocodilian (reptilian) multicameral lung type represents a Bauplan from which the respiratory organs of nonavian theropod dinosaurs and the lung-air sac system of birds appear to have evolved. However, many fundamental aspects of the evolution, development, and even the structure and function of the avian respiratory system still remain uncertain.

show abstract

Comparative Pulmonary Morphology and Morphometry: The Functional Design of Respiratory Systems

Cited by 16 publications

References 479 publications

Morphological and morphometric specializations of the lung of the Andean goose, Chloephaga melanoptera: A lifelong high-altitude resident

Morphological and morphometric specializations of the lung of the Andean goose, Chloephaga melanoptera: A lifelong high-altitude resident

Evolution of Air Breathing: Oxygen Homeostasis and the Transitions from Water to Land and Sky

Development, structure, and function of a novel respiratory organ, the lung-air sac system of birds: to go where no other vertebrate has gone

Contact Info

Product

Resources

About