Publisher's Synopsis
The thyroid gland is a metabolism hormone-producing gland in the lower part of the neck, below the Adam apple. It has two lobes attached to one another by a middle part called the isthmus and is located in front of the trachea. The thyroid produces essential hormones required by the body that help regulate metabolism, heart rate, blood pressure, and temperature. Thyroid hormones are also necessary for children to grow and develop.Thyroxine (T4) and triiodothyronine (T3) are the two most important hormones made by the thyroid. The gland also makes calcitonin, a hormone involved in calcium metabolism. A hormone made by the pituitary gland called thyroid stimulating hormone (TSH) acts to stimulate hormone production by the thyroid gland.The thyroid gland is located below the Adam apple wrapped around the trachea (windpipe), and it has a butterfly shape. A thin area of tissue in the gland's middle, known as the isthmus, joins the two thyroid lobes on each side. The thyroid uses iodine to produce vital hormones. Thyroxine, also known as T4, is the primary hormone produced by the gland. After delivery via the bloodstream to the body's tissues, a small portion of the T4 released from the gland is converted to triiodothyronine (T3), which is the most active hormone.Thyroid disease can result from conditions that cause over-or under-function of the thyroid gland. When the gland produces too much thyroid hormone, the condition is known as hyperthyroidism. When the gland does not function sufficiently, there is too little thyroid hormone produced (hypothyroidism). In addition to problems with the level of hormones made by the gland, both benign and malignant tumours (cancers) can cause enlargement of the thyroid gland or nodules (lumps) within the gland. Enlargement of the thyroid gland in the neck can cause symptoms that are directly related to the increase in the size of the organ (such as difficulty swallowing and discomfort in front of the neck).
