کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
2791347 1154870 2009 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
End-tidal CO2 in some aquatic mammals of large size
موضوعات مرتبط
علوم زیستی و بیوفناوری علوم کشاورزی و بیولوژیک علوم دامی و جانورشناسی
پیش نمایش صفحه اول مقاله
End-tidal CO2 in some aquatic mammals of large size
چکیده انگلیسی

While resting on land or at the water surface, the breathing frequency (f) of aquatic mammals of medium and large size is lower than in terrestrial mammals of similar body weight (W), the difference widening with the increase in W. The allometric function for aquatic mammals is f∝W−0.42 (f, breaths/min, W, kg) and that of terrestrial species is f∝W−0.25. We asked whether or not resting breathing at such low f would entail high values of alveolar CO2. End-tidal alveolar CO2 pressure, taken as representative of alveolar CO2 pressure, PaCO2, was measured from the expired gas during resting breathing in captive specimens of aquatic species trained to rest in proximity of their keepers, either on land (walrus and sea lion) or at the water surface (dolphin, orca, beluga and hippopotamus). Their f during the recordings ranged from less than 1 (orca) to 6 (walrus) breaths/min. The average PaCO2 values ranged from 32 to 42 mm Hg, the peaks being a few mm Hg higher. These values were similar or slightly higher than literature data of many terrestrial species, with no relation to the animal f or W. The quasi-normality of PaCO2 in large aquatic species breathing at rest, despite their exceptionally low f and normal metabolism, can be explained mainly by two factors, their large tidal volume/W, about three times the average terrestrial value, and their peculiar breathing pattern with sustained high lung volume during the expiratory pause. This latter is key in avoiding a substantial rise in PaCO2 during the inter-breath pause.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Zoology - Volume 112, Issue 2, 15 March 2009, Pages 77–85
نویسندگان
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