Anatomical and gravitational influences on cardiac displacement in snakes (Lepidosauria, Serpentes)

Radiographs of live, unanesthetized snakes were used to document the position of the heart in the body cavity during horizontal, head-up, and head-down postures. The extent of cardiac displacement observed during these postural changes differed substantially among the snakes examined, ranging from v...

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Bibliographic Details
Published in:Zoomorphology 1994-09, Vol.114 (3), p.169-175
Main Authors: Young, B A, Street, S L, Wassersug, R J
Format: Article
Language:English
Subjects:
Animals
Cardiovascular Physiological Phenomena
Crotalus
Gravitation
Heart - anatomy & histology
Heart - diagnostic imaging
Pericardium - anatomy & histology
Pericardium - diagnostic imaging
Posture - physiology
Radiography
Snakes - anatomy & histology
Snakes - physiology
Space life sciences
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Summary:Radiographs of live, unanesthetized snakes were used to document the position of the heart in the body cavity during horizontal, head-up, and head-down postures. The extent of cardiac displacement observed during these postural changes differed substantially among the snakes examined, ranging from virtually none in a thin-bodied arboreal snake to as much as three vertebral lengths (= half the length of the heart) in a heavy-bodied terrestrial Crotalus. The basis of this differential cardiac displacement is attributed to the anatomical "packaging" of the pericardial sac. In some snakes the pericardial sac is loosely suspended in the body cavity by the great vessels and connective tissue sheets. In contrast, in other snakes the pericardical sac is buttressed against the body wall, the lung, or the liver. We hypothesize that cardiac displacement during postural change may alter the pattern of blood flow in the aortae of snakes.
ISSN:0720-213X
1432-234X
DOI:10.1007/BF00403264