An experimental investigation into the functions of the eighth pair of nerves, or the glosso-pharyngeal, pneumogastric and spinal accessory / by John Reid.

  • Reid, John, 1809-1849.
Date:
[1839]
Catalogue details

Licence: Public Domain Mark

Credit: An experimental investigation into the functions of the eighth pair of nerves, or the glosso-pharyngeal, pneumogastric and spinal accessory / by John Reid. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    i Functions of the Eighth Pair of*Nerves. 6\ animals of equal or even superior strength, in which the nerves had been previously divided. And tliis is nothing more than what we should expect, when we remember that the effects of the diminished frequency of the Respiration are conjoined to those of the narcotic poison. Cause of Death after Section of the Vagi.—From what we have already said it is obvious, that though the animals in which the vagi have been divided generally die from morbid changes in the lungs, yet they occcasionally die from inanition produced by the derangement of the digestive organs. Experiment X. is an ex- ample of the latter mode of death. We are of course here sup- posing that means have been taken to insilre the access of a suf- ficient quantity of air into the lungs; otherwise the animal may die, suffocated from the arrestment of the movements of the muscles attached to the arytenoid cartilages. From the numerous experiments Ve have made upon the nervi vagi and their branches, Ave have arrived at the following conclu- sions. Pharyngeal Branches.—The pharyngeal branches of the vagi are entirely, or almost entirely, motor, and move the muscles of the pharynx and soft palate. Laryngeal Branches.—The superior laryngeal are almost entirely nerves of sensation, supplying the mucous surface of the larynx, and part of the pharynx, with sensitive filaments. The few motor filaments which they contain are distributed in and move the crico-thyroid muscles. The inferior laryngeal nerves arc ramified in and regulate the movements of all the muscles attached to the arytenoid cartilages, viz. the crico-ary- tenoidei postici and laterales, the thyro-arytenoidei, and ary- tenoidel. Tiie inferior laryngeals also furnish the sensitive fila- ments to the upper part of the trachea., a few to the mucous surface of the pharynx, and still fewer to the larynx. When any irritation is applied to the mucous membrane of the larynx in the healthy state, this does not excite the contraction of the muscles which approximate the arytenoid cartilages, by acting directlv upon them through the mucous membrane ; but this contraction takes place indirectly, and by a reflex action, in the performance of which the superior laryngeals act as the sensitive or afferent nerves, and the inferior laryngeals as the motor or ef- ferent nerves. It is also probable that those branches of the in- ferior laryngeal distributed in the muscular fibres of the trachea are motor. (Esophageal Branches.—The oesophageal filaments of the vagus are partly afferent and partly efferent nerves. In some animals, as in the rabbit, the section of the vagi in the neck is followed by arrestment of the passage of the food along the oesophagus