Thyroid Gland, and its Chemical Messengers

jaiedocere, thyroid

Thyroid Gland
and its Chemical Messengers

Thyroid Anatomy

Image source: UpToDate.


Your thyroid is located in your neck. It is part of the endocrine or hormone system and it makes and releases hormones that travel throughout the body. The thyroid gland is about about as big as a deck of cards and it’s shaped like a butterfly or bow-tie.

Who Controls the Thyroid

The thyroid gland, like all hormone or endocrine glands, is controlled through a complex system involving different parts of the brain, specifically the hypothalamus and the pituitary. We can imagine that the hypothalamus is the CEO giving orders to the pituitary which is like a manager encouraging the thyroid employee to produce hormones. In this analogy, everyone is inherently lazy: if the CEO isn’t on the manager or the manager isn’t talking to the employee then we won’t have enough hormone. While sometimes we can have thyroid problems as a result of the hypothalamus or pituitary, most of the time it is a problem with the thyroid itself.

Thyroid Chemical Messengers

Hormones work as chemical messengers carrying messages from one place in the body to another. In fact, thyroid hormones have effects on almost every part of the body. The thyroid produces four hormones, abbreviated as: T1, T2, T3 and T4. The number refers to how many iodine molecules are attached to the hormone molecule. The thyroid also makes the hormone calcitonin which helps to control how much calcium is found in the blood.

T3 is the active hormone, or messenger. It is very active, meaning it would start doing things as soon as it left the thyroid and would never get where it was going, so we turn it into T4 so it can travel throughout the body. When it gets to its end location it turns back into T3.

Thyroid hormones helps cells form energy, helps to burn carbohydrates and fat, helps to regulate body temperature, plays a role in hair, skin and nail growth, repairs brain cells, interacts with other hormone or endocrine organs like ovaries and adrenals, and plays a role in intestinal and immune function. Thyroid hormones play a crucial role in brain development of infants, which is why we check the thyroid function of all newborns.

How do I know if my thyroid is okay?

Testing thyroid function is not always straightforward.

Read How do I know if I have autoimmune thyroid disease? for a brief introduction.

References

Thanks to Alan Christianson, ND for the thyroid CEO/Manager analogy.

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