Thyroid Thyroid The thyroid gland, or simply the thyroid, is an endocrine gland in the neck, consisting of two lobes connected by an . It is found at the front of the neck, below the Adam's apple. The thyroid gland secretes thyroid hormones, which primarily influence the metabolic rate and protein synthesis. The hormones also have many other effects including those on development. The thyroid hormones triiodothyronine (T) and thyroxine (T) are created from iodine and tyrosine. The thyroid also produces the hormone calcitonin, which plays a role in calcium homeostasis. Hormonal output from the thyroid is regulated by thyroid-stimulating hormone
Thyroid cancer has also manifested itself on the European continent by the use of serum calcitonin measurements in patients with goiter to identify patients with early abnormalities of the parafollicular or calcitonin-producing cells within the thyroid gland. As multiple studies have demonstrated, the finding of an elevated serum calcitonin is associated with the finding of a medullary thyroid carcinoma in as high as 20% of cases. In Europe where the threshold for thyroid surgery is lower than in the United States, an elaborate strategy that incorporates serum calcitonin measurements and stimulatory tests for calcitonin has been incorporated into the decision to perform