Continuing our series on hormones, we next look at the thyroid and the delicate balance it creates to regulate our body. Endocrineweb.com says your thyroid gland is a small gland, normally weighing less than one ounce, located in the front of the neck. It is made up of two halves, called lobes that lie along the windpipe (trachea) and are joined together by a narrow band of thyroid tissue, known as the isthmus. The thyroid is situated just below your “Adams apple” or larynx.
The function of the thyroid gland is to take iodine, found in many foods, and convert it into thyroid hormones: thyroxine (T4) and triiodothyronine (T3).Thyroid cells are the only cells in the body which can absorb iodine. These cells combine iodine and the amino acid tyrosine to make T3 and T4. T3 and T4 are then released into the blood stream and are transported throughout the body where they control metabolism (conversion of oxygen and calories to energy).Every cell in the body depends upon thyroid hormones for regulation of their metabolism. The normal thyroid gland produces about 80% T4 and about 20% T3, however, T3 possesses about four times the hormone “strength” as T4.
The thyroid gland is under the control of the pituitary gland, a small gland the size of a peanut at the base of the brain (shown here in orange). When the level of thyroid hormones (T3 & T4) drops too low, the pituitary gland produces Thyroid Stimulating Hormone (TSH) which stimulates the thyroid gland to produce more hormones. Under the influence of TSH, the thyroid will manufacture and secrete T3 and T4 thereby raising their blood levels. The pituitary senses this and responds by decreasing its TSH production. One can imagine the thyroid gland as a furnace and the pituitary gland as the thermostat. Thyroid hormones are like heat. When the heat gets back to the thermostat, it turns the thermostat off. As the room cools (the thyroid hormone levels drop), the thermostat turns back on (TSH increases) and the furnace produces more heat (thyroid hormones).
The pituitary gland itself is regulated by another gland, known as the hypothalamus (shown in our picture in light blue). The hypothalamus is part of the brain and produces TSH Releasing Hormone (TRH) which tells the pituitary gland to stimulate the thyroid gland (release TSH). One might imagine the hypothalamus as the person who regulates the thermostat since it tells the pituitary gland at what level the thyroid should be set. (http://www.endocrineweb.com/conditions/thyroid/how-your-thyroid-works)
The thyroid is probably the most common of the glands to become diseased as low thyroid or high thyroid. A properly balanced thyroid gland efficiently burns fat, improves the feeling of wellbeing and helps with brain function. If this doesn’t happen, hormone replacement is prescribed. Indications of a low thyroid might be fatigue, weight issues, cold intolerance, dry skin, thinning or brittle hair and depression. As we age, the thyroid may produce fewer hormones. Testing for a thyroid issue is done using different processes. The most common is a blood test that checks the levels of the hormones of the thyroid (T3, T4 and TSH). These tests will give an accurate account of your thyroid hormone balance.
Because of the wide range of what is considered to be acceptable, many people remain undiagnosed for a thyroid disorder or diagnosed incorrectly. The replacement of thyroid hormones is a unique balancing process. T4 has to be converted to T3. With the appropriate tests, we can combine natural hormones that are tailored to the patient’s individual needs and restore their thyroid hormonal balance as part of their personalized age management plan. As with all hormone replacement treatment plans, proper dosage and scheduled monitoring is essential.
Do you have symptoms you believe are related to the thyroid being out of balance or not functioning properly? Comment below—we can help!