THE THYROID GLAND
What is the thyroid gland?
The thyroid gland is a butterfly-shaped endocrine organ that is situated in front of the neck. It has two halves, or lobes, that lie on either side of the trachea (windpipe), just below the “Adam’s apple”, and are joined together by a narrow band of thyroid tissue known as the isthmus. The thyroid makes thyroid hormones, which are discharged into the bloodstream and then conveyed to every tissue of the body. Thyroid hormones control body metabolism and affect many different organs, including brain, heart, liver, kidneys, muscles, bones and skin.
How the thyroid works?
Iodine is fundamental for thyroid-hormone production. It is found in many foods, especially, seafood, salt, bread, and milk. The thyroid uses dietary iodine to make thyroid hormones. These hormones are triiodothyronine (T3) and thyroxine (T4). These hormones are stored within the thyroid. When they are needed, they are released into the bloodstream and transported throughout the body attached to special carrier proteins.
The thyroid function is controlled by the pituitary gland, located at the base of the brain. When the level of thyroid hormones falls too low, the pituitary responds by producing thyroid-stimulating hormone (TSH). If the thyroid works normally, it responds to TSH by producing more hormones and thus raising the blood level of thyroid hormone back to normal.
- Blood measurements of T4 and TSH are the most important tests to determine the function of the thyroid gland.
- Thyroid ultrasonography is the recognized “gold standard” for an accurate and reliable assessment of gland volume and thyroid nodules.
Which are the most common diseases of the thyroid gland?
- Hypothyroidism: underactive thyroid gland
- Hyperthyroidism: hyperactive thyroid gland
- Thyroid nodules: lesions inside the thyroid gland
- Goiter: enlarged thyroid gland
- Thyroiditis: thyroid inflammation