Video Transcript
The underproduction of thyroid
hormones is called hypothyroidism. If hypothyroidism is caused by an
iodine deficiency, what condition can this result in? (A) Goiter, (B) Turner syndrome,
(C) cystic fibrosis, or (D) type one diabetes?
To answer this question, let’s
review the key facts about the thyroid hormones and their functions. As you may know, hormones are the
body’s chemical messengers. They are released from glands and
travel through the bloodstream to their target cells, where they can bring about
some form of response. This question talks specifically
about thyroid hormones. Thyroid hormones are produced by
the thyroid gland, which is a butterfly-shaped gland located at the base of the
neck.
Let’s take a closer look at the
structure of the thyroid gland. It is composed of many thyroid
follicles, one of which you can see here. Each follicle has a wall made up of
thyroid follicular cells and encloses a space or a cavity. These thyroid follicular cells are
the ones responsible for producing the thyroid hormones and releasing them into the
cavity of the thyroid follicle.
There are two types of thyroid
hormones, thyroxine and triiodothyronine. Thyroxine is called T4, since its
structure includes four iodine atoms. Tri- means three, so
triiodothyronine has three iodine atoms in its structure and is sometimes called
T3. Iodine, therefore, is crucial for
the production of both T3 and T4. The body doesn’t produce iodine
itself. So it’s important that we receive
enough iodine in our diet for our thyroid gland to function efficiently. When the body doesn’t receive
enough iodine, the thyroid hormones are secreted in lower quantities. This is called hypothyroidism,
where the word part “hypo-” means low. To compensate for this, the thyroid
gland enlarges to try and capture as much iodine as possible. This is called a goiter.
We now have all the information we
need to answer our question about what condition can result from hypothyroidism. The correct answer is (A),
goiter.
