Our hearts, brains, livers, kidneys and skin all rely on one tiny, often-overlooked, butterfly-shaped gland: our thyroid. Located just under our voice box, this little workhorse regulates several body functions and plays a huge role in metabolism — if we need more energy, for example, it pumps out more hormones to deliver it. When we were young, it was also a major driver of our growth and development.
Most of us have likely never given it a second thought - unless you've already had a thyroid condition. And the fact is, 20 million Americans today have some form of thyroid dysfunction or disease. Women are particularly affected, accounting for five to eight times more cases than men. The good news is that most of these conditions are fairly easy to treat. The bad news is that up to 60% of people with thyroid problems are unaware that we have them — and undiagnosed thyroid disease puts us at risk for a number of serious conditions.
January is National Thyroid Awareness month, making this the perfect time to gain a better understanding of how the thyroid works, identify the symptoms of common thyroid-related issues and diseases, and learn about testing and treatment options. This blog will provide an overview of the thyroid gland and explain how it works to regulate many of our bodies' vital functions.
What Is the Thyroid Gland?
The thyroid gland is a butterfly-shaped endocrine gland that is normally located in the lower front of the neck. The thyroid's job is to make hormones which are secreted into the blood and then carried to every tissue in the body. Thyroid hormone helps the body use energy, stay warm and keep the brain, heart, muscles, and other organs working as they should.
How does the Thyroid Gland Work?
The major thyroid hormone secreted by the thyroid gland is called T4 because it contains four iodine atoms. To exert its effects, T4 is converted to T3 by the removal of an iodine atom. This occurs mainly in the liver and in certain tissues where T3 acts, such as in the brain. The amount of T4 produced by the thyroid gland is controlled by another hormone, which is made in the pituitary gland located at the base of the brain, called thyroid stimulating hormone (abbreviated TSH). The amount of TSH that the pituitary sends into the bloodstream depends on the amount of T4 that the pituitary sees. For example, if the pituitary sees very little T4, then it produces more TSH to tell the thyroid gland to produce more T4. Once the T4 in the bloodstream goes above a certain level, the pituitary's production of TSH is shut off. This seems very complicated, but it's not. Consider the thyroid and pituitary acting like a heater and a thermostat. When the heater (thyroid gland) is off and it becomes cold, the thermostat (pituitary gland) reads the temperature and turns on the heater. When the heat rises to an appropriate level, the thermostat senses this and turns off the heater. Thus, the thyroid and the pituitary, like a heater and thermostat, turn on and off. This feedback loop keeps the levels of T4 in the blood stable and reacts to small changes immediately.
What Happens if it Stops Working Correctly?
Normally the thyroid gland produces the exact number of hormones needed to keep the body's metabolism running and in balance. As described earlier, the TSH secreted by the pituitary gland remains constant in blood circulation, but its levels may increase or decrease when T4 levels in the blood change. However, there are several disorders associated with the thyroid gland with most problems concerning the production of thyroid hormones. Either the thyroid gland produces too much hormone (called hyperthyroidism) or your thyroid does not produce enough hormone (called hypothyroidism), resulting in your body using energy faster or slower than it should.
In next week's blog, we will take an in-depth look at hyperthyroidism: the causes, symptoms and treatment options for one of the most common thyroid-related conditions.