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MedicineAnatomy and Physiology

Cardiovascular Control During Stimulated Hypergravity

Authors: Roger Hainsworth; LEEDS UNIV (UNITED KINGDOM)
Abstract:
A model of the circulation was developed using anesthetized dogs which allowed blood pressures and flows at different levels of the body to be changed in ways that simulated the events occurring during acceleration. In particular the responses were examined to decreases in pressure to the carotid baroreceptors and increases in pressure in the splanchnic circulation, changes that would occur during + Gz acceleration. Splanchnic congestion was found to elicit reflex vasoconstriction in the splanchnic. circulation itself as well as in the hind-limbs. There was an interaction between the effects of splanchnic distension and the carotid baroreceptor reflex resulting in nearly a doubling of the gain of the baroreflex. This research has defined a previously unknown mechanism which is likely to be of considerable importance in the maintenance of blood pressure during acceleration and could be of relevance to optimizing counter-G protection.

Limitations: APPROVED FOR PUBLIC RELEASE
Description: Final rept. 30 Sep 93-29 Sep 94
Pages: 9
Report Date: 22 DEC 94
Contract Number: F49620-93-1-0587
Report Number: A919092
Keywords relating to this report:
*ANTIMALARIALS
*BLOOD PRESSURE
*CARDIOVASCULAR SYSTEM
ACCELERATION
ANESTHESIA
CAROTID ARTERIES
CIRCULATION
CONGESTION
CONTROL
DOGS
MAINTENANCE
MODELS
REFLEXES
SENSE ORGANS
VASOCONSTRICTING
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