Avenues of extrapulmonary oxygen uptake in western painted turtles (Chrysemys picta belli) at 10 °C

Jackson, Donald C.; Rauer, Elizabeth M.; Feldman, R A; Reese, Scott A.

doi:10.1016/j.cbpb.2004.09.005

Cited by 11 publications

(16 citation statements)

References 33 publications

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“…fR buccopharyngeal epithelia, and/or the cloacal bursae (Jackson et al, 2004;King and Heatwole, 1994). Cloacal bursae are appendices to the cloaca that may be highly vascularised and used for aquatic respiration by actively ventilation the cloacal bursae with water (King and Heatwole, 1994).…”

Section: Speciesmentioning

confidence: 99%

Ventilation and gas exchange in two turtles: Podocnemis unifilis and Phrynops geoffroanus (Testudines: Pleurodira)

Cordeiro

Abe

Klein

2016

Respiratory Physiology & Neurobiology

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Turtles (Testudines) have two major taxa, Pleurodira and Cryptodira. To date, only limited data are available regarding the respiratory physiology of pleurodirans. To begin to address this, we studied ventilation and gas exchange in Podocnemis unifilis and Phrynops geoffroanus. Breathing pattern in both species could be described as episodic with breathing episodes separated by large non-ventilatory periods. We measured duration of inspiration and expiration, breathing frequency, duration of the non-ventilatory period (time between episodes), tidal volume, and oxygen consumption when breathing normoxia, hypoxia and hypercarbia at 25°C. In both species hypercarbia caused a greater increase in ventilation compared to hypoxia, increasing both breathing frequency and tidal volume. Minute ventilation and oxygen consumption in P. geoffroanus were the lowest described so far in testudines, indicating either extra-pulmonary gas exchange or a significantly lower metabolism. Oxidative costs of breathing, estimated using the regression method, was the highest described so far for any reptile. Further studies are necessary to better understand respiratory physiology in Phrynops and Podocnemis species.

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Section: Speciesmentioning

confidence: 99%

Ventilation and gas exchange in two turtles: Podocnemis unifilis and Phrynops geoffroanus (Testudines: Pleurodira)

Cordeiro

Abe

Klein

2016

Respiratory Physiology & Neurobiology

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“…The ecology of these freshwater turtles was recently reviewed (Ultsch, 2006). Because of the very low metabolic rate, induced by low temperature and entrance to a hypometabolic state, cutaneous gas exchange can partially or fully suffice to maintain aerobic respiration when the water is normoxic (Belkin, 1968a;Ultsch, 1985;Herbert and Jackson, 1985a;Jackson et al, 2001;Jackson et al, 2004;Ultsch, 2006). However, when the overwintering turtles encounter low oxygen levels or complete anoxia in the water, anaerobic metabolism is pivotal for maintaining physiological functions.…”

Section: The Anoxia Tolerant Turtlementioning

confidence: 99%

Tribute to P. L. Lutz: cardiac performance and cardiovascular regulation during anoxia/hypoxia in freshwater turtles

Overgaard

Gesser

Wang

2007

Journal of Experimental Biology

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SUMMARY Freshwater turtles overwintering in ice-covered ponds in North America may be exposed to prolonged anoxia, and survive this hostile environment by metabolic depression. Here, we review their cardiovascular function and regulation, with particular emphasis on the factors limiting cardiac performance. The pronounced anoxia tolerance of the turtle heart is based on the ability to match energy consumption with the low anaerobic ATP production during anoxia. Together with a well-developed temporal and spatial energy buffering by creatine kinase, this allows for cellular energy charge to remain high during anoxia. Furthermore, the turtle heart is well adapted to handle the adverse effects of free phosphate arising when phosphocreatine stores are used. Anoxia causes tenfold reductions in heart rate and blood flows that match the metabolic depression, and blood pressure is largely maintained through increased systemic vascular resistance. Depression of the heart rate is not driven by the autonomic nervous system and seems to arise from direct effects of oxygen lack and the associated hyperkalaemia and acidosis on the cardiac pacemaker. These intra- and extracellular changes also affect cardiac contractility, and both acidosis and hyperkalaemia severely depress cardiac contractility. However, increased levels of adrenaline and calcium may, at least partially, salvage cardiac function under prolonged periods of anoxia.

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“…Extant amphibians employ the skin for cutaneous gaseous exchange while in air, but amniotes do not. Semi-aquatic reptiles, such as turtles, can rely more on cutaneous gas exchange at cold temperatures when metabolic demands for oxygen uptake and carbon dioxide elimination can be met by low diffusion rates afforded by the integument [42]. Several groups of extant turtles (e.g.…”

Section: (A) Mode Of Obtaining Oxygenmentioning

confidence: 99%

Palaeophysiology of pH regulation in tetrapods

Janis

Napoli

Warren

2020

Phil. Trans. R. Soc. B

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The involvement of mineralized tissues in acid–base homeostasis was likely important in the evolution of terrestrial vertebrates. Extant reptiles encounter hypercapnia when submerged in water, but early tetrapods may have experienced hypercapnia on land due to their inefficient mode of lung ventilation (likely buccal pumping, as in extant amphibians). Extant amphibians rely on cutaneous carbon dioxide elimination on land, but early tetrapods were considerably larger forms, with an unfavourable surface area to volume ratio for such activity, and evidence of a thick integument. Consequently, they would have been at risk of acidosis on land, while many of them retained internal gills and would not have had a problem eliminating carbon dioxide in water. In extant tetrapods, dermal bone can function to buffer the blood during acidosis by releasing calcium and magnesium carbonates. This review explores the possible mechanisms of acid–base regulation in tetrapod evolution, focusing on heavily armoured, basal tetrapods of the Permo-Carboniferous, especially the physiological challenges associated with the transition to air-breathing, body size and the adoption of active lifestyles. We also consider the possible functions of dermal armour in later tetrapods, such as Triassic archosaurs, inferring palaeophysiology from both fossil record evidence and phylogenetic patterns, and propose a new hypothesis relating the archosaurian origins of the four-chambered heart and high systemic blood pressures to the perfusion of the osteoderms. This article is part of the theme issue ‘Vertebrate palaeophysiology’.

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Avenues of extrapulmonary oxygen uptake in western painted turtles (Chrysemys picta belli) at 10 °C

Cited by 11 publications

References 33 publications

Ventilation and gas exchange in two turtles: Podocnemis unifilis and Phrynops geoffroanus (Testudines: Pleurodira)

Ventilation and gas exchange in two turtles: Podocnemis unifilis and Phrynops geoffroanus (Testudines: Pleurodira)

Tribute to P. L. Lutz: cardiac performance and cardiovascular regulation during anoxia/hypoxia in freshwater turtles

Palaeophysiology of pH regulation in tetrapods

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