If you need to get your thyroid checked out, your primary care physician may refer you to a gland specialist. The thyroid is one of several important organs in the human body that produce and secrete hormones. Even though some organs are small, each one produces chemical substances that regulate cell activity.
Normally functioning glands are vital to good health. Taken together, all the glands in the body are referred to as the endocrine system. Endocrinology is the medical study of hormones, including diseases and conditions associated with hormonal imbalance and damage to the glands.
Hormones regulate the body’s growth and metabolic rates, sexual function, and a wide variety of chemical processes inside us. Think of hormones as chemical messengers that the body creates to exchange information between sets of cells to orchestrate the proper functioning of different body parts.
Glands fall into one of three types:
- Some glands manufacture something released from the body, such as tears, saliva, and perspiration.
- Other glands, which are part of the immune system, release disease-fighting substances. Swollen neck glands during a bad cold are a sign that the body is fighting off infection.
- Finally, there are glands that release hormones which tell the body how to function and how to grow (develop). Glands that secrete hormones are part of the endocrine system. Puberty (sexual maturation) depends on the endocrine system.
The word endocrine comes from Greek: “endo” means within, while “crinis” means to secrete. That is precisely what glands in the endocrine system do: secrete chemicals inside the body.
The major glands of the endocrine system are the:
- Pineal body
- Reproductive organs (ovaries and testes)
The endocrine system works under a feedback system, not unlike a temperature-sensing room thermostat:
“For the hormones that are regulated by the pituitary gland, a signal is sent from the hypothalamus to the pituitary gland in the form of a ‘releasing hormone,’ which stimulates the pituitary to secrete a ‘stimulating hormone’ into the circulation.”
As its name suggests, the stimulating hormone tells the recipient gland to secrete its hormone. Just like heat in a cold room after the furnace has been turned on, the hypothalamus and pituitary gland sense when the level is “within normal limits” (healthy) and then switch off secretion of both the stimulating and the releasing hormones. The gland slows its hormone secretion rate accordingly.
In a manner very similar to a thermostat for heat regulation, a well-balanced endocrine system ensures that all the glands in the body operate normally.
The thyroid is a gland located in the lower front area of the neck. It has one job: make thyroid hormones that regulate body metabolism – the physical and chemical processes of the body. It also contributes to bone growth and, in children, the development of the brain and nervous system.
Thyroid hormones are secreted into the blood and transported to every tissue throughout the body. The hormones secreted by the thyroid help control blood pressure, heart rate, digestion, muscle tone, and reproductive functions. They help the body stay warm, use energy, and keep the brain, heart, muscles, and other organs in good working order.
The hypothalamus and pituitary gland are in charge of the thyroid hormones and proper secretion to maintain a healthy metabolism. There are two thyroid hormones: T4 and T3. The pituitary stimulates the thyroid to start making T4 and T3 with the thyroid-stimulating hormone TSH. At the same, the hypothalamus sends out the thyrotropin-releasing hormone TRH.
Remember our wall thermostat? In the same way, it can be set too high (sweltering) or too low (freezing), the body’s glands can produce too much or too little of their special hormones. This creates a medical problem.
Hormone disease also happens when the body fails to respond to hormones appropriately. Hormone levels are also affected by stress, infection, and changes in the blood’s fluid and electrolyte balance.
By far, the most common endocrine disease in the U.S. is diabetes, but there are many others that we will examine in a future article.
Suffice it to say that doctors prescribe hormone supplements for low hormone levels and take measures to control over-production of a bodily hormone. There are also foods that help regulate the body’s hormones naturally.