Brain temperature and therete mirabile ophthalmicum in the Zebra finch (Poephila guttata)

@article{Bech2004BrainTA,
  title={Brain temperature and therete mirabile ophthalmicum in the Zebra finch (Poephila guttata)},
  author={Claus Bech and Uffe Midtg{\aa}rd},
  journal={Journal of comparative physiology},
  year={2004},
  volume={145},
  pages={89-93}
}
Summary1.Brain and colonic temperatures were measured in five Zebra finches (Poephila guttata) with a mean body weight of 0.013 kg.2.The mean body-to-brain temperature difference (0.18 °C) was lower than in all other previously studied species of birds, indicating a decreased ability to cool the brain in the Zebra finch.3.Morphological studies of the head vasculature revealed that therete mirabile ophthalmicum was very simple. The absence of a well-developed rete is presumed to be responsible… 

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References

SHOWING 1-10 OF 24 REFERENCES
Role of theRete mirabile ophthalmicum in maintaining the body-to-brain temperature difference in pigeons
TLDR
Therete mirabile ophthalmicum of pigeons plays a central role in the maintenance of the body-to-brain temperature difference which may be important in avoiding brain damage during core hyperthermia.
Brain temperatures in birds
TLDR
The body-to-brain temperature difference was maintained nearly constant within a species over a wide range of cloacal and air temperatures, and varied in magnitude from 0.80°C in the Roadrunner to 1.29°C on average, which may be important in avoiding brain damage during core hyperthermia.
Independence of brain and body temperatures in flying American kestrels, Falco sparverius.
TLDR
The establishment of delta T during flight may be correlated with increased respiratory and corneal evaporation, and apparently confines most stored body heat to noncranial regions, thus protecting brain tissue from thermal extremes.
Brain temperature in pigeons: Effects of anterior respiratory bypass
TLDR
A role for the cornea in evaporative cooling, at least when respiratory evaporation is impaired, is suggested, and is consistent with the hypothesis that buccopharyngeal and cornealevaporation are coupled to brain cooling.
Temperature changes of the hypothalamus and body core in ducks feeding in cold water
TLDR
The measurements do not support the assumption that the hypothalamic region in the duck is exposed to substantially greater temperature fluctuations than other thermosensitive parts of the body core.
Gaseous Metabolism and Water Relations of the Zebra Finch, Taeniopygia castanotis
  • W. Calder
  • Environmental Science
    Physiological Zoology
  • 1964
TLDR
The investigation of the zebra finch, Taeniopygia castanotis (= Poephila guttata), reported herein represents an effort in that direction to reveal hitherto unsuspected adaptations of xerophilous species.
Water Economy and Metabolism of Two Estrildine Finches
TLDR
The zebra finch of Australia was chosen as a xerophilous form to compare with the tropical black-rumped waxbill of Africa, because it seemed likely that these two species might reveal the maximum difference in physiological adjustments for the regulation of water to be found within the subfamily Estrildinae.
Evaporative cooling in the zebra finch
TLDR
O2-Verbrauch und Gesamt-Wasserverdunstung wurden bei australischen Zebrafinken gemessen gemessen durch Strahlung, Konvektion and Ableitung für die Wüstenvögel erforderlichen Wärmeabfluss einzig durch Verdunstund auf dem normalen Niveau halten.
The role of hypothalamic temperature in the control of panting in the chicken exposed to heat
1. In unanaesthetized chickens, the temperatures of the hypothalamus, colon and skin have been recorded in relation to the onset and cessation of thermally induced panting.
The significance of changes in the temperature of the skin and body core of the chicken in the regulation of heat loss
  • S. Richards
  • Chemistry, Medicine
    The Journal of physiology
  • 1971
1. The relationship between the temperatures of the hypothalamus, colon and skin and the control of heat loss mechanisms at ambient temperatures from 20 to 40° C has been studied in unanaesthetized
...
1
2
3
...