[The effect of gravity on blood volumes in the main cervical arteries in healthy humans].
The study of the effect of gravity on blood volumes in the main cervical arteries was conducted with voluntary participation of 50 normal men and women. Blood volumes were determined with the ultrasound technique. The circulatory effect of gravity was simulated by administration of the active standing test. Circulating volumes in the common carotid, internal carotid and vertebral arteries in the supine position were 464, 342 and 110 ml/min, respectively and decreased significantly up to 352, 262 and 84 ml/min, respectively in the standing position. The orthostatic reduction in the volume of blood circulating along the vertebral artery was proportional to that in the internal carotid artery. Specific contribution of changes in vascular capacity to the blood volume reduction was shown to be predominant.
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D000293:Adolescent; D000328:Adult; D001488:Basilar Artery / Q000502:physiology*; D001783:Blood Flow Velocity / Q000502:physiology; D001810:Blood Volume / Q000502:physiology; D002339:Carotid Arteries / Q000502:physiology*; D005260:Female; D006112:Gravitation; D006304:Health Status; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009333:Neck; D014711:Vertebral Artery / Q000502:physiology*