Thyroid vertebrates. In fish, it is usually located below the gills and is not always divided into distinct lobes. However, in some teleosts, patches of thyroid tissue are found elsewhere in the body, associated with the kidneys, spleen, heart, or eyes. In tetrapods, the thyroid is always found somewhere in the neck region. In most tetrapod species, there are two paired thyroid glands – that is, the right and left lobes are not joined together. However, there is only ever a single thyroid gland in most mammals, and the shape found in humans is common to many other species. In larval
Thyroid thyroid, which over time destroys the cells involved in its uptake. The chosen first-line treatment will depend on the individual and on the country where being treated. Surgery to remove the thyroid can sometimes be performed as a transoral thyroidectomy, a minimally-invasive procedure. Surgery does however carry a risk of damage to the parathyroid glands and the nerves controlling the vocal cords. If the entire thyroid gland is removed, hypothyroidism will naturally result, and thyroid hormone substitutes will be needed. An underactive thyroid gland results in hypothyroidism. Typical symptoms are abnormal weight gain, tiredness, constipation, heavy menstrual bleeding, hair loss,