Previous studies of the blood of the teal suggested possible mechanisms which would enable flight at high altitude. Investigations of the animal's oxygen consumption (VO2), respiratory rate, tidal volume, and cardiac output (CO) were made to provide further information on hypoxic resistance. VO2, determined by the open circuit method, increased in the blue winged teal (BW) 40% from a normoxic value of .96 ml (g.hr)-1 to 1.32 ml (g.hr)-1 at a PO2 = 73 mm Hg. VO2 of the green winged (GW) increased 45% from 0.92 ml (g.hr)-1 to 1.43 ml (g.hr)-1. Respiratory rate of BW was unchanged by hypoxia from its normoxic value of 42 breath (min)-1. There is, however, nearly a 35% increase in ventilation brought about by an increase in tidal volume from a normoxic value of .006 ml (g.breath)-1 to .01 ml (g.breath)-1. CO, assisted by the Fick method for both species, was .34 l (kg.min)-1 under normoxic conditions, with a stroke volume of 1.4 ± .2 ml (kg)-1 at a heart rate of approximately 245 beats (min)-1. Reduction of the PO2 was without demonstrable effect on cardiac frequency; however, CO showed a slight decrease to 0.23 l (kg.min)-1 with a stroke volume of 1.2 ± .1 ml (kg)-1. The data suggest these species respond to hypoxia by increasing pulmonary ventilation with little alteration in cardiovascular system function.
|Original language||English (US)|
|State||Published - Jan 1 1977|
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