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THE EFFECT OF THE COMPOSITION OF THE INSPIRED AIR ON THE CIRCULATION THROUGH THE BRAIN
Author(s) -
Irving Laurence,
Welch Mary Scott
Publication year - 1935
Publication title -
quarterly journal of experimental physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0370-2901
DOI - 10.1113/expphysiol.1935.sp000670
Subject(s) - cerebral blood flow , inhalation , blood flow , differential effects , blood pressure , anatomy , anesthesia , chemistry , cardiology , medicine
The flow of blood through the femoral vein and longitudinal sinus of dogs was examined by comparison of the A‐V oxygen differences. Inhalation of 10 per cent. CO 2 in O 2 increased blood‐flow through the brain of anæsthetised dogs to the estimated extent of from two to four times. At the same time flow through the hind leg was diminished, often to less than half the normal rate. These vascular changes indicate a differential vascular control giving a preferential consideration to the brain. Alveolar O 2 deficiency did not cause the differential change, but the actual degree of anoxemia was not serious. During CO 2 inhalation the R.Q. of the brain is much larger than in the leg. The R.Q. indicates the process of equilibration of the tissue with a change in pressure of CO 2 , and demonstrates that the pressure of CO 2 changes more quickly in the brain than in the leg. The stimulus for differential control of flow may originate in the brain itself, but the result may be reinforced by, or it may even originate in a site extrinsic to the tissue.