Frequently Asked Questions about:
Thyroid Gland

Note:  Information provided below is intended as a source of information and a guide.  For specific details about your own health, speak to  your doctor. 

(Revised 8/28/2000)

Answer:  Everyone has a thyroid gland which makes and releases just the right amount  of thyroid hormone into our blood stream.  Thyroid hormone helps control our mood, temperature regulation, the way our body metabolizes food, our weight, pulse rate, dryness or moistness of our skin, quality of our hair, mood, strength and even helps regulate our bowel movements. There is hardly a part of our body that does not depend on thyroid hormone for completely normal function.  As long as it works as it was intended to you will not know you even have a thyroid gland.  Only when your thyroid gland malfunctions and makes too much or too little thyroid hormone are you likely to find out about your thyroid gland. 

When your thyroid gland is overactive and makes too much thyroid hormone the condition is known as hyperthyroidism but when your thyroid gland doles out too little thyroid hormone it is considered to be under active and hypothyroidism is the problem. 

The amount of thyroid hormone in your blood stream tells your doctor whether you have a. An Overactive thyroid-hyperthyroidism, b. an underactive thyroid –hypothyroidism or normal thyroid function-euthyroidism.  Your doctor will probably want to rely on a measurement of not just thyroid hormone, but another hormone called TSH (thyroid stimulating hormone).  

What’s so special about TSH?

The thyroid requires a go ahead signal from thyroid stimulating hormone –TSH (a pituitary gland hormone) to make normal amounts of the thyroid hormone Thyroxine. When the thyroid gland becomes overactive and blood thyroxine levels are more than the pituitary expects TSH levels fall.  Conversely when less than expected amounts of thyroid hormone appear in the blood stream TSH levels increase. When the thyroid functions normally thyroxine and TSH levels remain stable.

Thus although there are exceptions :

Thyroxine high + TSH Low = Hyperthyroidism

Thyroxine low + TSH High = Hypothyroidism

Now that you know how to interpret thyroid hormone tests let’s get on with the questions about thyroid hormones and health.   

Learn more about:

The Overactive Thyroid - Hyperthyroidism
The Underactive Thyroid - Hypothyroidism