Carbon dioxide transport

Oxygen and carbon dioxide dissociation curves were constructed for the blood of the Nile monitor lizard, Varanus niloticus, acclimated for 12h at 25 and 35°C. The oxygen affinity of Varanus blood was low when Pco2 w a s in the range of in vivo values (25°C: P50 = 34.3 at PCOCO2 = 21 mmHg; 35°C: P50 = 46.2 mmHg at PCOCO2 = 35 mmHg; 1 mmHg = 133.3 Pa), and the oxygen dissociation curves were highly sigmoidal (Hill's n = 2.97 at 25°C and 3.40 at 35°C). The position of the O2 curves was relatively insensitive to temperature change with an apparent enthalpy of oxygenation (ΔH) of −9.2kJ mol−1. The carbon dioxide dissociation curves were shifted to the right with increasing temperature by decreasing total CCOCO2 at fixed PCOCO2, whereas the state of oxygenation had little effect on total blood CO2 content. The in vitro buffer value of true plasma (Δ[HCO3−]pl/-ΔpHpl) rose from 12.0 mequiv pH−1−1 at 25°C to 17.5 mequiv pH−11−1 at 35°C, reflecting a reversible increase of about 30% in haemoglobin concentration and haematocrit levels during resting conditions in vivo.

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Oxygen and Carbon Dioxide Transport

Quantitative Human Physiology ◽

10.1016/b978-0-12-800883-6.00064-1 ◽

2017 ◽

pp. 656-664 ◽

Cited By ~ 2

Author(s):

Joseph Feher

Keyword(s):

Carbon Dioxide ◽

Carbon Dioxide Transport

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Carbon Dioxide Transport and Excretion

Fish Physiology - Fish Respiration ◽

10.1016/s1546-5098(08)60263-0 ◽

1998 ◽

pp. 229-281 ◽

Cited By ~ 17

Author(s):

Bruce Tufts ◽

Steve F. Perry

Keyword(s):

Carbon Dioxide ◽

Carbon Dioxide Transport

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The Physiology of Carbon Dioxide Transport in Insect Blood

Journal of Experimental Biology ◽

10.1242/jeb.27.2.158 ◽

1950 ◽

Vol 27 (2) ◽

pp. 158-174 ◽

Cited By ~ 1

Author(s):

L. LEVENBOOK

Keyword(s):

Carbon Dioxide ◽

Dissociation Constant ◽

Temperature Coefficient ◽

Carbonic Acid ◽

Apparent Dissociation Constant ◽

Carbon Dioxide Transport ◽

High Co2 ◽

The Third ◽

A Value ◽

Dissociation Curves

1. The pH of the blood of the third instar Gastrophilus larva is 6.64 at 38° C. with a pH-temperature coefficient of -0.007 Per 1° C. rise in temperature. 2. The total CO2 content of the blood varies from 40.6 to 131.4 vol. % with an average of 72.4 vol. %. The CO2 content of the tissues minus the cuticle is very close to, and follows the variations in, the CO2 content of the blood. 3. The CO2 tension in the blood is from 300 to 500 mm. Hg. From 30 to 50% of the CO2 is in solution, the rest in the form of bicarbonate. Carbamate formation does not occur in the blood. 4. The ‘apparent’ dissociation constant for carbonic acid, (pK'1), has a value of 6.08 (S.D. ±0.06) at 38° C. and 6.19 (s.d. ±0.13) at 16° C. 5. CO2 dissociation curves have been drawn for 38 and 16° C. The slope of the curves indicates that the whole of the CO2 is given off at zero CO2 tension, and that the blood is adapted for functioning at high CO2 tensions.

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