Hand-book of physiology (1892) (14578524880)

Identifier: handbookofphysio00bake (find matches)

Title: Hand-book of physiology

Year: 1892 (1890s)

Authors: Baker, W. Morrant, (William Morrant), 1839-1896 Harris, Vincent Dormer Kirkes, William Senhouse, 1823-1864. Hand-book of physiology. 13th ed

Subjects: Physiology Human physiology

Publisher: London : John Murray

Contributing Library: Francis A. Countway Library of Medicine

Digitizing Sponsor: Open Knowledge Commons and Harvard Medical School

Text Appearing Before Image:

he next chapter.Of course, the undulations spoken of are only seen in records ofarterial blood pressure ; they are more clearly marked in thearteries nearer the heart than in those more remote, in thesmaller arteries the amount of the pressure as well as the indication of the systolic rise of pressure, being, comparatively speaking,small. In order to record the undulations of arterial pressure, for somepurposes it is better to use Ficks Spring Kymograph than themercurial manometer. Two forms of this instrument are shownin figs1 176 and 177. It consists of a hollow C-spring, filledwith fluid, the interior of which is made to communicate with the OH. VI.) AMOUNT OF BLOOD-PRESSUKE. 211 artery by means of a flexible metal tube and cannula. Inresponse to the pressure, transmitted to its interior, the springtends to straighten itself, and the movement thus produced iscommunicated by means of a lever to a writing style and so to arecording apparatus. This instrument obviates the errors which

Text Appearing After Image:

Fig. 176.—A form of Picks Spring Kymograph, a, tube to be connected with artery ; c,hollow spring, the movement of which moves b, the writing lever; e, screw to regulateheight of b ; d, outside protective spring; g, screw to fix on the upright of the support. might be caused by the inertia of the mercury in the mercurialmanometer ; it also shows in more detail the variations of theblood pressure in the vessel during and after each ind: vddual beatof the heart. In fig. 178 is seen a tracing taken with Kicks Kymographfrom an artery of a dog. As regards the actual amount of blood pressure, from observa-tions which have been made by means of the mercurial mano-meter, it has been found that the pressure of blood in the carotidof a rabbit is capable of supporting a column of 2 to 3*5 inches(50 to 90 mm.) of mercury, in the dog 4 to 7 inches (100 to175 mm.), in the horse 5 to 8 inches (125 to 200 mm.), and inman the pressure is estimated to be about the same. P 2 CIRCULATION OF THE BLOOD.

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1892

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