What is Your Thyroid Gland?

The thyroid gland is located in the middle of the lower neck, below the larynx (voice box) and just above your clavicles (collarbones). It is shaped like a “bow tie” having two halves (lobes), the right lobe and the left lobe joined by an “isthmus”. You can’t always feel a normal thyroid gland.

Your thyroid gland may be small, but it has an important job. It regulates the rate at which every part of your body works. This is called your metabolism. When your thyroid is healthy, your metabolism stays at a steady pace, not too fast or too slow.

By controlling your metabolism, a healthy thyroid keeps your body working right and keeps you feeling good. The speed of your metabolism affects the workings of your organs, such as your heart and brain. Your metabolism acts on your digestive system to control how efficiently you burn calories. It keeps your skin, hair and nails healthy and your muscles and nerves in good condition. It can even influence how you think and feel.

Your thyroid gland regulates your metabolism by making thyroid stimulating hormone (TSH) - a chemical that carries messages from the thyroid to the rest of the body through the bloodstream. Your thyroid gland makes thyroid hormone from iodine, which is absorbed from the food you eat. When a large amount of thyroid hormone is produced, the cells work faster. When less thyroid hormone is produced, the cells work slower. To control the amount of thyroid hormone that’s produced, the pituitary gland monitors the level of thyroid hormone in your blood and tells the thyroid when it needs to make more.

In general, levels of TSH in the bloodstream go up when there’s less thyroid hormone and down when there’s more thyroid hormone.

• With hypothyroidism, the thyroid produces less thyroid hormone than normal. This prompts the pituitary to send extra TSH into the bloodstream to try to get the thyroid to make more hormone.
• With hyperthyroidism, the thyroid produces more thyroid hormone than normal. The pituitary then cuts back on the amount of TSH it sends into the bloodstream.

Read about thyroid disease.