The thyroid is an endocrine gland, which means it produces hormones in the body. It is located at the bottom front of the neck and is controlled by a nearby gland called the pituitary gland. The pituitary gland secretes thyroid-stimulating hormone (TSH), which tells the thyroid when to produce its own hormones. The thyroid hormones control cell growth and metabolism. Several medical conditions can affect the thyroid and thyroid hormones and cause metabolism to either speed up or slow down. Thyroid conditions affect women more often than men.
Description
The thyroid gland is often described as a butterfly-shaped organ because it has two segments, or lobes that are connected but sit on either side of the windpipe. Thyroid cells known as follicular cells absorb iodine from the diet and use it to produce two hormones that travel through the bloodstream and regulate all body processes.
Function
Thyroid hormones--tri-iodothyronine (T3) and thyroxine (T4)--regulate body temperature, oxygen use, calcium balance, heart rate and the speed at which all your organs work. That includes the rate at which your body breaks down food and uses it for energy, which affects your weight. When the thyroid is properly functioning, it produces just the right amount of these hormones to keep body functions balanced.
Problems
Hypothyroidism is condition in which too little thyroid hormone is produced because the thyroid is damaged or inflamed and the body literally slows down. This is sometimes the result of surgery to correct other thyroid problems in which all or part of the thyroid is removed or destroyed. Hypothyroidism can cause weight gain, depression, fatigue, irregular menstrual cycles, decreased sex drive and dry hair and skin.
Hyperthyroidism is an overproduction of thyroid hormones, ultimately causing weight loss, depression, fatigue, insomnia, shortness of breath, irregular heartbeat, weakness, nervousness and fatigue. A sign of Graves disease, a form of hyperthyroidism, is a slight or pronounced bulging of the eyes.
There are several types of thyroid cancer, all uncommon, but the most often diagnosed form, papillary thyroid cancer, is frequently seen in people between the ages of 30 and 50. Thyroid nodules or cysts are small growths of thyroid tissue that are common, even in young people, and are most often benign.
Iodine deficiency causes a condition known as goiter, in which the thyroid becomes enlarged. This condition is rare in the U.S. because salt is enriched with iodine.
Diagnosis
Many different types of blood tests, ultrasounds, scans and biopsies are used to diagnose specific thyroid conditions. If symptoms point to a thyroid problem, an initial blood test is usually performed to determine which specific type of advanced testing is necessary. At some point, your primary care physician will refer you to an endocrinologist, or hormone specialist, for further care.
It is especially important to diagnose and control hypothyroidism in pregnant women to avoid miscarriage or birth defects.
Treatments
Most people with thyroid cancer have their thyroids surgically removed because this type of cancer has a high rate of recurrence. After removal, the area is often treated with radioactive iodine, which destroys any remaining cancer cells as well as healthy thyroid tissue.
Radiation treatment is also used for recurring thyroid cancer and to treat goiter and some forms of hyperthyroidism. Once the thyroid is removed or destroyed by radiation, hormone replacement medication must be taken for a lifetime. If only part of the organ is removed, and you are still producing thyroid hormone, you may not have to take medication.
