Lesson 12: The Glandular System (page 4 of 9)

The Pituitary gland is known as the “master gland.”

 

Thyroid Gland

The thyroid gland is an endocrine gland located just under the Adam’s apple in the throat. It secretes a hormone into the bloodstream called thyroxine, which controls the body’s metabolism—the rate at which the body burns calories for energy. It also controls the body’s utilization of fat. Too little thyroxine can cause excessive fat to accumulate which can lead to weight gain. It can also result in a low level of energy, low blood pressure, and a lowered basal body temperature, making one feel colder than usual especially in the hands and feet. Such a condition is called underactive thyroid or hypothyroidism.

 

Who is at Risk for Underactive Thyroid?

To perform its function properly, the thyroid needs sufficient quantities of trace minerals like zinc, copper, selenium, iron, and particularly iodine: as well as adequate amounts of vitamins such as A, C, E and particularly the B vitamins. If the thyroid does not get the nutrition it needs an underactive thyroid can be the result. The habit of eating nutrient-poor fast and processed foods is the ultimate cause for some individuals. Many children have poor eating habits which can eventually lead to problems with the thyroid gland later in life. The condition called goiter, an enlargement of the thyroid gland, was common in areas where there is little iodine in the soil until iodine was added to salt in order to increase dietary intake of this important trace mineral.

Dieting, especially starvation diets which severly restrict caloric intake, is another common cause of underactive thyroid. Starvation slows the body’s metabolism as it learns to expend energy more efficiently to conserve calories for the next “famine.” After a starvation diet we have a tendency to gain even more weight than we took off, and we may find it even harder to lose weight the next time we try. A low-calorie diet can suppress the thyroid function within seven to 24 hours. After one to three months of such dieting, there is a danger of permanently inhibiting the thyroid function.

Another contributor to an underactive thyroid for some individuals is regular use of caffeine. Caffeine can slow the thyroid by suppressing the production of cortisol, a hormone secreted by the adrenal glands which is essential to thyroid function.

 

What are the Symptoms of Underactive Thyroid?

If you are overweight, easily chilled, have little energy, low blood pressure, a tendency toward depression, and find it difficult to get going in the morning, you should consider an underactive thyroid as a possible cause. An underactive thyroid is also a major contributor, if not the major cause, of painful muscular conditions such as fibromyalgia. An underactive thyroid also affects the liver’s ability to produce HDL’s or “good” cholesterol, the kind that pulls “bad” cholesterol out of the bloodstream. It has been estimated that approximately 14% of cases of high serum cholesterol may be caused by an underactive thyroid.

The best way to find out if your thyroid gland is underactive is to take your basal body temperature, which is your temperature when at complete rest. Take your temperature by mouth for three days in a row, first thing in the morning before you get out of bed. Any activity can raise your body temperature so shake the thermometer down before you go to bed and have it beside your bed when you wake up. If your body temperature is below 97.6 degrees Fahrenheit for three days in a row, you have a problem with your thyroid gland.

You may want to see your doctor to determine the severity of your thyroid problem and to discuss your treatment options. In cases of severe hypothyroidism, you doctor may want to put you on synthetic thyroxin. This may be necessary for some individuals, especially those who have had their thyroid glands surgically removed. If your underactive thyroid is not so severe your doctor’s test might not indicate a problem. This is because doctors are usually looking for problems that are severe enough to require drug treatment. Doctors will usually ignore an underactive thyroid that does not meet their criteria for drug treatment. However, even mildly underactive thyroids that don’t require drug treatment can never-the-less result in all of the symptoms mentioned above, including weight gain and low energy. In such cases, lifestyle and dietary changes and nutritional supplementation may be your best option.

The condition that occurs when the thyroid is functioning below normal is known as hypothyroidism [hypo-, under]. This results in a lowered basal metabolism (decreased body temperature) with the symptoms of excessive sensitivity to cold (feeling cold all the time), lethargy (sluggishness or low energy level), and excessive weight gain.

The condition that occurs when the thyroid is functioning above normal is known as hyperthyroidism [hyper-, above]. The symptoms are the opposite of hypothyroidism including excessive sensitivity to heat (feeling hot all the time) and difficulty gaining weight.

Which of the following is most correct?

 A. The prefix “hyper-” means “above or excessive.”
 B. The prefix “hypo-” means “above or excessive.”
 C. The prefix “hyper-” means “below or under.”
 D. The prefix “hypo-” means “below or under.”
 E. Both A and D are correct.
 F. Both B and C are correct.