Physiology : A manual for students and practioners / by Theodore C. Guenther and Augustus E. Guenther.

  • Guenther, Theodore C. (Theodore Charles)
Date:
1903
Catalogue details

Licence: Public Domain Mark

Credit: Physiology : A manual for students and practioners / by Theodore C. Guenther and Augustus E. Guenther. 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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    tion iif llic sccn'tioii, and since tlic ciizyuK'.s iorinod arc ppccilic Milislaiici'S, tlic lormcr arc taken to l»c tli«'ir source and desi^Miatcd as ziivKKjen (jniiiitlis. The forerunner oi'ptijaliii i.s called ptya/ino- (jni ; of jnjtsiii, /iiji>iiiiu(/eii, etc. The. pre SSI I rr in the duct of the submaxillary has been observed at 1!M) nun. Hi;, while the blood pressure in the carotid at the liiiK' was but 112 mm. Hg. The question of the amount of heat trivi'u otrdurini; the activity of the <rland is still unsettled. Lud- wiir and Spiess oriizinaily determined the saliva to be 1° warmer than the bhtod in the carotid. Ilcideidiain, by the thermo-electric method, found the diHerence to become greater on stimulation of the sym[)athetic. The rlectrical changes in glands are analogous to the action currents iu muscles. The current may be ingoing, outgoing, or diphasic in character. Nervous Factors.—The salivary glands have a cranial and a symjiitUirtic iierve-supj)ly, whose influence may be illustrated by the results obtained from the submaxillary of the dog. When the rhonla tipnjiaHi, whose fibres are cranial in orgin, is stimulated with weak induction shocks, the saliva obtained is relatively abundant, thin, aud watery, containing not more than 1 to 2 per cent, of solids. The gland becomes redder in color, the veins are distended, and the blood sliows a distinct pulse, indicating a dila- tation of the small arteries and that the chorda tympani carries dilator fibres. Stimulation of the symjiaihetk fibres produces a scanty secretion, which is thick and turbid and may contain 6 per cent, of solids. The gland becomes paler, the blood flow is les- sened, showing that a vasoconstriction has occurred. Circulatory Factors.—That the character of the secretion is not entirely due to the changes in the amount of blood flowing to the glands is shown l)v the following facts: 1. The blood-flow may be cut off entirely when stimulation of the chorda tymjiani still gives a secretion. 2. Injection of atrojiine ]»roduces an increased flow of blood, but no secretion upon stimulation of the chorda. 3. Injection of hydrochlorate of quinine gives a vascular dila- tation, but no secretion until the nerve is stimulated. When the chorda is irritated with shocks of increasing intensity, it is found tiiat the amount of water and .salts secreted increases projiortionately to a maximum limit, which for salts is about 0.77 per cent., no matter what the condition of the gland mav be. The
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