Thyroid and Thymus

Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: CHAPTER II. PHYSIOLOGY OF THE THYROID. History.?Theories regarding the physiology of the thyroid have been numerous. Wharton thought it was merely a cosmetic organ whose function was to produce a nice, soft, roundness of the neck. Other authors thought that it acted as a mechanical support to the larynx,...
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Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: CHAPTER II. PHYSIOLOGY OF THE THYROID. History.?Theories regarding the physiology of the thyroid have been numerous. Wharton thought it was merely a cosmetic organ whose function was to produce a nice, soft, roundness of the neck. Other authors thought that it acted as a mechanical support to the larynx, and protected this organ against cold. Boerhaave thought that it acted as a cushion whose gentle pressure served as a modulator of the voice. Morgagni, Santorini, Winslow and Lalouette thought that the gland was in direct communication with the larynx, and that it probably had an excretory canal emptying into the region of the vocal cords; and that under such conditions the secretion of the thyroid acted as a lubricant for these cords. As late as 1870 Ricou believed in the existence of this excretory canal; some other authors believed that the thyroid communicated directly with the esophagus and considered the foramen cecum as the point of outlet of the canal. For quite a long time the thyroid was considered as a mechanical regulatory organ of the blood circulation and was regarded as an arterial reservoir intercalated between the cephalic and the carotico-subclavian systems; filled with blood, the gland was thought capable of compressing the carotids, thus diminishing the quantity of blood going into the brain. Compared to a sponge capable of derivating or giving up at will the blood destined to the cerebral organs, the thyroid was then regarded as a safety-vent for the cerebral circulation. There is no need to say that these hypotheses are for the most part purely fanciful and are not supported by any experimental facts. However, it might be incorrect to claim that the thyroid has no effect whatsoever on the cerebral circulation, as this gland receives its nerve supply fr...