Compensatory phenomena in the distribution of the blood during stimulation of the splanchnic nerve / by D.J. Edwards.

  • Edwards, Dayton James, 1882-
Date:
[1914]
Catalogue details

Licence: Public Domain Mark

Credit: Compensatory phenomena in the distribution of the blood during stimulation of the splanchnic nerve / by D.J. Edwards. Source: Wellcome Collection.

Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.

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    MEASUREMENTS OF THE BLOOD-FLOW 1. Flow through the head. The experiments upon the blood- pressure in the external jugular vein gave results that indicate an increased flow through the head during stimulation of the splanchnic nerve. The method, however, was not applicable to quantitative determinations. The experiments now to be de- scribed were undertaken with this end in view. It was also hoped that the data obtained would give information regarding the proportional amount of compensation for the diminished portal flow which is afforded by the head circuit. The blood-flow in the external jugular vein was taken as the index of flow through the head, because it is the principal vessel for the return of the blood from this part. In the results of these experiments three things are obvious—first, vasoconstric- tion in the splanchnic area produces a marked increase in the blood-flow through the head; second, the changes in the flow occur in the same general manner as the changes in blood- pressure within the vein; and third, there is no evident diminu- tion in the flow coincident with the second phase in the increase in arterial blood pressure. It will be seen from table IV that the average blood-flow prior to the stimulation of the splanchnic nerve was about 1.99 cc. in a second and the average systemic blood pressure corre- sponding to this blood-flow was 0.89 mm. Hg. In terms of a systemic pressure of 100 mm. Hg, this would give a flow of 2.23 cc. per second, a value that is close to the average noraial of 2.4 cc. per second obtained by Burton-Opitz.^' Stimulation of the splanchnic nerve with current of moderate strength for an average period of forty-four seconds gave an increase of about 12.5 per cent in the amount of blood-flow through this vein. In table IV are arranged the results of five experiments upon the flow in the jugular vein. Let us turn for a moment to the proportional compensatory action afforded by this circuit. If we take the average normal flow in the external jugular as 144 cc. per minute, 2.4 cc. per