The thyroid is one of the largest endocrine glands in the body. This gland is found in the neck inferior to (below) the thyroid cartilage (also known as the Adam’s apple in men) and at approximately the same level as the cricoid cartilage. The thyroid controls how quickly the body burns energy, makes proteins, and how sensitive the body should be to other hormones.
Thyroid cancer refers to any of four kinds of malignant tumors of the thyroid gland: papillary, follicular, medullary or anaplastic. Papillary and follicular tumors are the most common. They grow slowly and may recur, but are generally not fatal in patients under 45 years of age. Medullary tumors have a good prognosis if restricted to the thyroid gland and a poorer prognosis if metastasis occurs. Anaplastic tumors are fast-growing and respond poorly to therapy.
The function of the thyroid gland is to take iodine, found in many foods, and convert it into thyroid hormones: thyroxine (T4) and triiodothyronine (T3). Thyroid cells are the only cells in the body which can absorb iodine. These cells combine iodine and the amino acid tyrosine to make T3 and T4. T3 and T4 are then released into the blood stream and are transported throughout the body where they control metabolism (conversion of oxygen and calories to energy). Every cell in the body depends upon thyroid hormones for regulation of their metabolism. The normal thyroid gland produces about 80% T4 and about 20% T3, however, T3 possesses about four times the hormone “strength” as T4.
The thyroid gland is located low in the front of the neck, below the Adam’s apple. The gland is shaped like a butterfly and wraps around the windpipe or trachea. The two wings or lobes on either side of the windpipe are joined together by a bridge, called the isthmus, which crosses over the front of the windpipe. 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.
Thyroid is an indispensable, peer-reviewed journal for clinicians, clinical investigators, and basic scientists in thyroid research, as well as molecular endocrinologists, cell biologists, pharmacologists, biochemists, and all those who want to be kept up to date on the latest research in laboratory diagnostics.
Hyperthyroidism is an excess of thyroid hormone resulting from an overactive thyroid gland. Symptoms can include increased heart rate, weight loss, depression, and cognitive slowing. Treatment is by medication, the use of radioactive iodine, thyroid surgery, or reducing the dose of thyroid hormone.
The symptoms of hyperthyroidism tend to reflect the rapid metabolism that results from an oversupply of thyroid hormone. Common symptoms include anxiety, insomnia, rapid weight loss, diarrhea, high heart rate, high blood pressure, eye sensitivity/bulging and vision disturbances, and many other concerns. A lengthier list of symptoms and risks is featured in Graves’ disease and Hyperthyroidism: Risks and Symptoms.
Like hypothyroidism, many symptoms of mild hyperthyroidism mimic those of normal pregnancy. However, anyone experiencing symptoms such as significant weight loss, vomiting, increased blood pressure, or persistently fast heart rate should have blood tests to look for hyperthyroidism.