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The Gravity of Giraffe Physiology
Author and Affiliation:
Hargens, Alan R.(NASA Ames Research Center, Moffett Field, CA United States);
Holton, Emily M. [Technical Monitor]
Abstract: By virtue of its tallness and terrestrial environment, the giraffe is a uniquely sensitive African animal to investigate tissue adaptations to gravitational stress. One decade ago, we studied transcapillary fluid balance and local tissue adaptations to high cardiovascular and musculoskeletal loads in adult and fetal giraffes. Previous studies by Goetz, Pattersson, Van Citters, Warren and their colleagues 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 how giraffes avoid pooling of blood and tissue fluid (edema) in dependent tissue of the 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 edema include precapillary vasoconstriction and low permeability of capillaries to plasma proteins. Other anatomical adaptations in dependent tissues of giraffes represent developmental adjustments to high and variable gravitational forces. These include vascular wall hypertrophy, thickened capillary basement membrane and other connective tissue adaptations. Our results in giraffe suggest avenues of future gravitational research in other animals including humans.
Publication Date: Jan 01, 1997
Document ID:
20020042320
(Acquired May 10, 2002)
Subject Category: LIFE SCIENCES (GENERAL)
Document Type: Preprint
Meeting Information: International Conference on Comparative Physiology and Biochemistry; 31 Aug. - 5 Sep. 1997; Skukuza; South Africa
Contract/Grant/Task Num: RTOP 199-26-12-34
Financial Sponsor: NASA Ames Research Center; Moffett Field, CA United States
National Inst. of Health; Bethesda, MD United States
National Science Foundation; United States
National Geographic Society; Washington, DC United States
Organization Source: NASA Ames Research Center; Moffett Field, CA United States
Description: 1p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: No Copyright
NASA Terms: PHYSIOLOGY; ANIMALS; GRAVITATION; CARDIOVASCULAR SYSTEM; CONNECTIVE TISSUE; HEART; BLOOD PRESSURE; ARTERIES; EDEMA
Availability Source: Other Sources
Availability Notes: Abstract Only
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