The thyroid is a butterfly-shaped gland located in the front of the neck. Inside the thyroid gland are millions of follicles. These follicles produce hormones which are used by every cell of the body.
Inside the follicle, thyroglobulin protein binds to iodine. When this occurs, thyroglobulin splits and forms the hormones. Hypothyroidism, or underactive thyroid, is a condition in which the thyroid fails to produce a sufficient amount of hormones necessary for normal cell function. Hyperthyroidism is a disease in which the thyroid produces too many hormones. This imbalance of hormone production can result in symptoms that develop across many organ systems and which can range from mild to severe.
Hypothyroidism occurs when not enough thyroglobulin proteins bind to iodine, decreasing the amount of hormones produced. Hormone replacement drugs are used to treat patients with hypothyroidism, in order to bring hormone levels back to normal.
Hyperthyroidism occurs when too many thyroglobulin proteins bind to iodine, increasing the amount of hormones produced. Hyperthyroidism is treated with drugs that bind to iodine and partially block the production of hormones, bringing the hormone level back down to normal.