Studies on the conditions of activity in endocrine glands. II, The secretory innervation of the thyroid gland / by W.B. Cannon and McKeen Cattell.

  • Walter Bradford Cannon
Date:
[1916?]
Catalogue details

Licence: Public Domain Mark

Credit: Studies on the conditions of activity in endocrine glands. II, The secretory innervation of the thyroid gland / by W.B. Cannon and McKeen Cattell. Source: Wellcome Collection.

    5/22
    each perifollicular plexus the finest fibrils reach out and end in knob- like enlargements on the basal end of the gland cells. From the analogy of other glands provided with secretory nerves, we should expect that the cells of the thyroid would be supplied solely by fibres from the autonomic nervous system. The histological evidence, just cited, that only non-medullated fibres enter the gland, gives con- firmation to that surmise. These fibres, however, might be derived from both the sympathetic and the cranial divisions of the autonomic system, or from either division alone. It is a matter of considerable significance for understanding the relation of the thyroid to the bodily economy to learn their origin. Anatomical evidence. After careful anatomical and embryological dissections Briau (7) reported that the thyroid nerves arise from the cervical sympathetic trunk, leaving that trunk at different levels, but originating especially (in man) from the middle cervical ganglion. This mass of nerve cells usually lies upon, or close to, the inferior thy- roid artery, hence the name “thyroid ganglion”’ assigned to it by Hal- ler. It corresponds to the inferior cervical ganglion of the dog and cat. Even what in man has been described as the inferior cervical ganglion is frequently found fused with the first thoracic. It is this fusion of several ganglionic masses at the top of the thorax that makes the stellate. In man the fibres passing out from the middle (inferior) cervical ganglion form plexuses around the thyroid arteries, Briau states, but chiefly around the inferior artery. According to Poirier and Charpy (8) and other anatomists, branches from the superior cervical gan- glion make the superior thyroid plexus about the artery of that name, and penetrate the gland along with it. Henle’s observation that the superior laryngeal nerve, and Lindemann’s observation that the re- current laryngeal each sends two or three filaments to the gland, were confirmed by Briau in all his dissections. In the cat the inferior cervical ganglion lies low in the neck, and the superior cervical is situated well above the level of the thyroid carti- lage. The inferior thyroid artery along which in man filaments from the inferior ganglion pass to the gland is inconstant in the cat, and even when present is small. The superior thyroid artery is a regular branch of the common carotid. Langley states (9) that occasionally in the cat a small “accessory” ganglion is found on the cervical sym- * pathetic trunk, about the level of the superior thyroid artery, which sends off gray fibres to that artery. In most animals this ganglion is part of the superior cervical.
    No text description is available for this image
    No text description is available for this image
    No text description is available for this image