Thyroid dysgenesis thyroid gland may be located anywhere along the path of the descent of the thyroid during its embryological development, although it is most commonly located at the base of the tongue, just posterior to the foramen cecum of the tongue. In this location, an aberrant or ectopic thyroid gland is known as a "lingual thyroid". If the thyroid fails to descend to even higher degree, then the resulting final resting point of the thyroid gland may be high in the neck, such as just below the hyoid bone. Parts of ectopic thyroid tissue ("accessory thyroid tissue") can also occur, and
Thyroid storm to sympathetic activation (see below). Sympathetic nervous system activation during times of stress may also play a significant role in thyroid storm. Sympathetic activation increases production of thyroid hormone by the thyroid gland. In the setting of elevated thyroid hormone, the density of thyroid hormone receptors (esp. beta-receptors) also increases, which enhances the response to catecholamines. This is likely responsible for several of the cardiovascular symptoms (increased cardiac output, heart rate, stroke volume) seen in thyroid storm. According to newer theories, thyroid storm results from allostatic failure in a situation where thyrotoxicosis hampers the development of non-thyroidal illness syndrome, which