StatPearls

StatPearls

Book. 2018 01

Authors:

Abstract
Goiter is the enlargement of the thyroid gland. Nontoxic goiter is thyroid gland enlargement with no disturbance in the thyroid function. It is not due to inflammation or neoplasia. Abnormalities of iodine supplies or metabolism always lead to nontoxic goiter. Thyroid gland normally weighs about 25 grams. It is a butterfly-shaped gland located in the anterior triangle of the neck just in front of the larynx and trachea. It is composed of right and left lobes with a connecting isthmus. The isthmus lies against the second and the third tracheal rings with the lobes extending on either side, from the thyroid cartilage superiorly to the fourth tracheal ring inferiorly. The thyroid gland secretes thyroid hormones (Thyroxin/T4 and triiodothyronine/T3)  in response to thyrotropic hormone (TSH) of the pituitary gland stimulation. They are important for body cells metabolism. It also secretes calcitonin hormone that has an important role in calcium metabolism. With decrease thyroid hormone production due to iodine deficiency as an example, TSH release will increase and this in the long-term will lead to thyroid follicles hyperplasia and as a result increase in thyroid gland size.

PMID: 29489295

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