iThei mdcdaelcinfd o c elllllrlllll tThe hlcinfd olsbdkpvouv“Knowledge will bring you the opportunity
to make a difference.”
— Claire Fagin2. BASIC THYROID KNOWLEDGE
So What the Heck Is a Thyroid?
The thyroid gland is a butterfly-shaped organ located in the neck below
the Adam’s apple. It produces thyroid hormones, which affect the func-
tion of just about every organ system in the human body.
Thyroid hormones are responsible for the crucial tasks of stimulat-
ing metabolism of the foods we eat, extracting vitamins, and produc-
ing energy from food. They are also vital to the production of other
hormones as well as to the growth and development of our nervous
system.
The thyroid has been called the “thermostat” of the body as it maintains
our temperature. Indirectly, thyroid function affects every reaction in the
human body since the temperature has to be just right for these reactions
to take place properly.^15
Thyroid Hormone Production
The thyroid gland has multiple small narrow cavities called follicles filled
with a clear material known as thyroglobulin (sometimes called colloid),
which is produced by a layer of thyroid epithelial cells known as thyro-
cytes. This material contains tyrosine, an amino acid that is a starting
material used for thyroid hormone synthesis. Thyroglobulin functions as
a reservoir for materials used in thyroid production, including the storage
of iodine.
Iodide absorbed from food circulates in our blood and is absorbed into
the thyroid gland, where it must be converted into a form usable by the