Thyroid Disorders: Hyperthyroidism, Hypothyroidism & Thyroidectomy

An error occurred trying to load this video.

Try refreshing the page, or contact customer support.

Coming up next: Parathyroid Gland: Calcium Metabolism, Osteoclasts & PTH

You're on a roll. Keep up the good work!

Take Quiz Watch Next Lesson
Your next lesson will play in 10 seconds
  • 0:07 Thyroid Gland
  • 0:47 Goiter
  • 1:48 Hypothyroidism
  • 3:24 Hyperthyroidism
  • 4:14 Graves' Disease
  • 4:52 Lesson Summary
Save Save Save

Want to watch this again later?

Log in or sign up to add this lesson to a Custom Course.

Log in or Sign up

Speed Speed
Lesson Transcript
Instructor: Rebecca Gillaspy

Dr. Gillaspy has taught health science at University of Phoenix and Ashford University and has a degree from Palmer College of Chiropractic.

The thyroid gland produces hormones that help set your metabolic rate. This lesson will discuss conditions of the thyroid gland, including hyperthyroidism and hypothyroidism, and their related symptoms.

Thyroid Gland

We previously learned that the thyroid gland is found at the base of your neck and lies just below your Adam's apple. This gland produces hormones that are important to your metabolism, known as T3 and thyroxine (T4). When this gland is performing as it should, you enjoy a normal metabolic rate. However, if the gland produces too many or too few hormones, you may experience fluctuations in your energy level, disruption of sleep, intolerance to temperatures, and difficulty controlling your weight. In this lesson, we will learn about disorders of the thyroid gland and what happens when the gland is overactive or underactive.


Iodine is needed for the thyroid to produce the metabolic hormones T3 and T4.
Iodine Needed for Thyroid Hormones

When we first learned about the thyroid gland, we took note to the fact that the trace mineral iodine must be in your diet in order for your thyroid to make the metabolic hormones T3 and T4. If iodine is deficient in your diet, it can lead to the development of a goiter. A goiter is defined as an enlargement of the thyroid gland due to a lack of iodine in the diet. The word 'goiter' originates from the Latin language and refers to the throat, and if you were to look at a person with a goiter, the distinguishing characteristic would be a lump, or enlargement, at the base of the throat.

Goiters were once common in American Midwestern states because the soil was iodine-deficient, and people in that region did not have access to seafood, which is a food that's rich in iodine. This earned the Midwest the nickname 'The Goiter Belt.' In modern-day America, goiters due to iodine deficiency are no longer common because our salt is iodized, but goiters are still a problem in some areas of the world.


If the thyroid gland does not make enough thyroid hormone, the result is a condition called hypothyroidism, or simply an underactive thyroid. Because we know that the prefix 'hypo' means 'less than normal,' and we see that the word 'thyroid' is contained in this condition's name, it's easy to recall this term because the name describes the condition. Literally, the thyroid gland is producing less-than-normal amounts of thyroid hormone. Since we know that the thyroid hormones play an important role in regulating your body's metabolism, it makes sense that a decrease in these hormones would lead to symptoms such as a loss of energy, an increased need for sleep, an intolerance to cold, a slow pulse, constipation, weight gain, and depression. It's almost as if the body of a person with hypothyroidism shifts into low gear.

An underproduction of thyroid hormones can come about due to a number of factors, including disease, radiation therapy, certain medications, or thyroid surgery. A thyroidectomy is an operation to surgically remove all or part of the thyroid gland. This might be necessary if a person is diagnosed with thyroid cancer or some other condition of the thyroid gland. As you might suspect, if untreated after the surgery, this person would experience a decreased metabolic rate. Therefore, after a thyroidectomy, a person may need to take a synthetic thyroid hormone medication to prevent hypothyroidism.

To unlock this lesson you must be a Member.
Create your account

Register to view this lesson

Are you a student or a teacher?

Unlock Your Education

See for yourself why 30 million people use

Become a member and start learning now.
Become a Member  Back
What teachers are saying about
Try it risk-free for 30 days

Earning College Credit

Did you know… We have over 200 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it risk-free for 30 days!
Create an account