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Developmental adaptations to gravity in animalsTerrestrial animals have adapted to a constant gravitational stress over millions of years. Tissues of the cardiovascular system and lumbar spine in tall species of animals such as the giraffe are particularly well adapted to high and variable vectors of gravitational force. Swelling of the leg tissues in the giraffe is prevented by a variety of physiological mechanisms including (1) a natural 'antigravity suit', (2) impermeable capillaries, (3) arterial-wall hypertrophy, (4) variable blood pressures during normal activity, and (5) a large-capacity lymphatic system. These adaptations, as well as a natural hypertension, maintain blood perfusion to the giraffe's brain. The intervertebral disk is another tissue that is uniquely adapted to gravitational stress. Tall and large terrestrial animals have higher swelling pressures than their smaller or aquatic counterparts. Finally, the meniscus of the rabbit knee provides information on the effects of aging and load-bearing on cartilaginous tissues. Such tissues within the joints of animals are important for load-bearing on Earth; these connective tissues may degenerate during long-duration space flight.
Document ID
19910013403
Document Type
Technical Memorandum (TM)
Authors
Hargens, Alan R.
(NASA Ames Research Center Moffett Field, CA, United States)
Date Acquired
September 6, 2013
Publication Date
February 1, 1991
Subject Category
Space Biology
Report/Patent Number
NAS 1.15:102228
A-89232
NASA-TM-102228
Accession Number
91N22716
Funding Number(s)
PROJECT: RTOP 199-21-12
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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