New perspectives on the evolution of lung ventilation mechanisms in vertebrates

Brainerd, Elizabeth L.

doi:10.1007/s00898-999-0002-1

Cited by 67 publications

(80 citation statements)

References 54 publications

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“…Gular pumping is not present in alligators (Brainerd, 1999;Farmer and Carrier, 2000a). Some movement of air in and out of the buccal region in alligators was measured in this ( Fig.·1) and other studies; however, these volumes do not contribute to gas exchange (Farmer and Carrier, 2000b;Gans and Clark, 1976;Naifeh et al, 1970aNaifeh et al, ,b, 1971.…”

Section: Discussionmentioning

confidence: 99%

Terrestrial locomotion does not constrain venous return in the American alligator,Alligator mississippiensis

Munns

Hartzler

Bennett

et al. 2005

Journal of Experimental Biology

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SUMMARY The effects of treadmill exercise on components of the cardiovascular(heart rate, mean arterial blood pressure, central venous pressure, venous return) and respiratory (minute ventilation, tidal volume, breathing frequency, rate of oxygen consumption, rate of carbon dioxide production)systems and on intra-abdominal pressure were measured in the American alligator, Alligator mississippiensis, at 30°C. Alligators show speed-dependent increases in tidal volume and minute ventilation,demonstrating that the inhibition of ventilation during locomotion that is present in some varanid and iguanid lizards was not present in alligators. Exercise significantly increases intra-abdominal pressure; however,concomitant elevations in central venous pressure acted to increase the transmural pressure of the post caval vein and thus increased venous return. Therefore, despite elevated intra-abdominal pressure, venous return was not limited during exercise in alligators, as was the case in Varanus exanthematicus and Iguana iguana. Respiratory cycle variations in intra-abdominal pressure, central venous pressure and venous return indicate that, at high tidal volumes, inspiration causes a net reduction in venous return during active ventilation and thus may act to limit venous return during exercise. These results suggest that, while tonically elevated intra-abdominal pressure induced by exercise does not inhibit venous return,phasic fluctuations during each breath cycle may contribute to venous flow limitation during exercise.

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Section: Discussionmentioning

confidence: 99%

Terrestrial locomotion does not constrain venous return in the American alligator,Alligator mississippiensis

Munns

Hartzler

Bennett

et al. 2005

Journal of Experimental Biology

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“…Accessory mechanisms for lung ventilation may increase tidal volume or alleviate constraints on breathing under certain environmental or behavioural conditions (Baumel et al 1990;Brainerd 1999;Owerkowicz et al 1999;Boggs 2002). Based on the reported involvement of the pelvis in breathing in birds (Baumel et al 1990;Ruben et al 1997Ruben et al , 2003 and crocodylians (Rathke 1866;, pelvic aspiration has been hypothesized to be a primitive breathing mechanism for the Archosauria , despite the fact that the proposed pelvic breathing mechanisms of birds and crocodylians are very different.…”

Section: Introductionmentioning

confidence: 99%

Archosaurian respiration and the pelvic girdle aspiration breathing of crocodyliforms

Claessens

2004

Proc. R. Soc. Lond. B

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Birds and crocodylians, the only living archosaurs, are generally believed to employ pelvic girdle movements as a component of their respiratory mechanism. This in turn provides a phylogenetic basis for inferring that extinct archosaurs, including dinosaurs, also used pelvic girdle breathing. I examined lung ventilation through cineradiography (high-speed X-ray filming) and observed that alligators indeed rotate the pubis to increase tidal volume, but did not observe pelvic girdle movement contributing to lung ventilation in guinea fowl, emus or tinamous, despite extensive soft-tissue motion. Re-examination of fossil archosaurs reveals that pubic rotation evolved in basal crocodyliforms and that pelvic girdle breathing is not a general archosaurian mechanism. The appearance of pelvic aspiration in crocodyliforms is a striking example of the ability of amniotes to increase gas exchange or circumvent constraints on respiration through the evolution of novel accessory breathing mechanisms.

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“…Screamers are widespread in the wetlands of South America and consist of at least four species, all of which lack uncinates but are capable of powered flight, walking and swimming (Del Hoyo et al, 1992-1999. As for the importance of uncinate processes as sites of attachment for respiratory or locomotor muscles, these functions are not necessarily mutually exclusive, and definitive experiments have yet to be conducted to test hypotheses regarding breathing and locomotion in birds.…”

mentioning

confidence: 99%

“…Furthermore, although dorsoventral movements of the sternum are known to be an integral part of the breathing mechanics in birds (Zimmer, 1935;Brainerd, 1999), EMG studies of respiratory muscles have been performed mainly on anaesthetised birds in a supine or restrained body position, using needle electrodes (Zimmer, 1935;Kadono, 1963;Fedde et al, 1964). There are no EMG studies examining the effect of restricting sternal movements on the activity of the respiratory muscle groups in birds, despite the fact that body positioning is known to alter respiratory movements due to the effect of gravity on the large muscle mass attached to the sternum (Zimmer, 1935).…”

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confidence: 99%

Activity of three muscles associated with the uncinate processes of the giant Canada goose Branta canadensis maximus

Codd

Boggs

Perry

et al. 2005

Journal of Experimental Biology

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The activity of three muscles associated with the uncinate processes, (i) external intercostal, (ii) appendicocostalis and (iii) external oblique, were examined using patch and sew-through electrodes during sitting, standing and moderate speed treadmill running in the giant Canada goose. The external intercostal muscles demonstrated no respiratory activity, being active only during running, suggesting they play some role in trunk stabilisation. The appendicocostalis and external oblique muscles are respiratory muscles, being active during inspiration and expiration, respectively. The activity of the appendicocostalis muscles increased during sitting, suggesting that the uncinate processes in birds play an important role in facilitating lateral flaring of the rib cage when sternal rocking is prevented. We suggest that the uncinate processes in birds facilitate movements of the ribs and sternum during breathing and therefore are integral to the breathing mechanics of birds.

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New perspectives on the evolution of lung ventilation mechanisms in vertebrates

Cited by 67 publications

References 54 publications

Terrestrial locomotion does not constrain venous return in the American alligator,Alligator mississippiensis

Terrestrial locomotion does not constrain venous return in the American alligator,Alligator mississippiensis

Archosaurian respiration and the pelvic girdle aspiration breathing of crocodyliforms

Activity of three muscles associated with the uncinate processes of the giant Canada goose Branta canadensis maximus

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