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December 19, 2011

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Thyroid Anatomy Illustration

Picture of the Thyroid

Image Source: MedicineNet, Inc.

The thyroid is a butterfly-shaped gland located in the front of the neck just below the Adams apple. The gland wraps around the windpipe (trachea) and has a shape that is similar to a butterfly formed by two wings (lobes) and attached by a middle part (isthmus).

The thyroid gland works like a tiny factory that uses iodine (mostly from the diet in foods such as seafood and salt) to produce thyroid hormones. These hormones help to regulate the body's metabolism and effects processes, such as growth and other important functions of the body.

The two most important thyroid hormones are thyroxine (T4) and triiodothyronine (T3), representing 99.9% and 0.1% of thyroid hormones respectively. The hormone with the most biological power is actually T3. Once released from the thyroid gland into the blood, a large amount of T4 is converted to T3 - the active hormone that affects the metabolism of cells throughout our body.

Thyroid Conditions

Thyroiditis : Inflammation of the thyroid gland which can release an excess of thyroid hormones into the blood stream, resulting in a temporary hyperthyroid state. Once the thyroid gland is depleted of thyroid hormones, the patient commonly goes through a hypothyroid (low thyroid) phase.
Thyroid Nodule : The term "thyroid nodule" refers to any abnormal growth that forms a lump in the thyroid gland. A thyroid nodule can occur in any part of the gland. Some nodules can be felt quite easily, while others can be hidden deep in the thyroid tissue or located very low in the gland where they are difficult to feel.
Hyperthyroidism Slideshow : Watch this slideshow on hyperthyroidism - a condition in which an overactive thyroid gland produces an excessive amount of thyroid hormones. Learn causes, symptoms and treatment for hyperthyroidism.
Hyperthyroidism: Hyperthyroidism is a condition in which an overactive thyroid gland is producing an excessive amount of thyroid hormones that circulate in the blood.
Hypothyroidism: Hypothyroidism is a condition characterized by abnormally low thyroid hormone production.
Thyroid Cancer: There are 4 major types of thyroid cancer -- papillary, follicular, medullary, and anaplastic. The most common symptom of thyroid cancer is a lump, or nodule, that can be felt in the neck.

Thyroid Tests

Thyroid Blood Tests: Blood testing is now commonly available to determine the adequacy of the levels of thyroid hormones. These blood tests can define whether the thyroid gland's hormone production is normal, overactive, or underactive.
Thyroid Scan: In a thyroid scan, iodine is labeled with a radioactive tracer, and a special camera is used to measure how much tracer is absorbed from the bloodstream by the thyroid gland.
Fine-Needle Aspiration Biopsy of the Thyroid: A procedure commonly used to determine whether a nodule in the thyroid gland is benign or malignant. A fine gauge needle is placed into the nodule and a drop of blood is withdrawn. The cells are studied under the microscope by a pathologist.
Thyroid Peroxidase Test: A blood test done to detect autoantibodies directed against thyroid peroxidase (TPO), an enzyme in the thyroid gland that is very important to the production of thyroid hormones.