Abstract:
:Because it is so tall, the giraffe, Giraffa camelopardalis, provides an important animal model for investigating adaptive mechanisms to orthostatic (gravitational) pressure changes. Previous physiological studies of the giraffe have concentrated on arterial blood pressures in the heart and neck. Briefly, these investigations revealed that arterial pressure near the giraffe heart is about twice that in humans, to provide more normal blood pressure and perfusion to the brain. Another important question is that of how giraffes avoid pooling of blood and tissue fluid (oedema) in dependent tissues of their extremities. As monitored by radiotelemetry, the blood and tissue fluid pressures that govern transcapillary exchange vary greatly with exercise. These pressures, combined with a tight skin layer, move fluid upward against gravity. Other mechanisms that prevent oedema include precapillary vasoconstriction and low permeability of capillaries to plasma proteins.
journal_name
Naturejournal_title
Natureauthors
Hargens AR,Millard RW,Pettersson K,Johansen Kdoi
10.1038/329059a0subject
Has Abstractpub_date
1987-09-03 00:00:00pages
59-60issue
6134eissn
0028-0836issn
1476-4687journal_volume
329pub_type
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