Thyroid and the endocrine system

The thyroid gland is part of the endocrine system. The system is responsible for the production of hormones and, through this, the regulation of many processes.

Organs of the endocrine system

Three organs are involved in the production and regulation of thyroid hormones:

-Hipothalamus
-Hipophysis
-Thyroid

The essence of the regulation process is negative feedback.

The hypothalamus is located in the brain. Its lower part is called the pituitary gland. First the hypothalamus produces a hormone called TRH (TSH releasing hormone). This TRH will stimulate the pituitary gland, where it will produce TSH (thyroid stimulating hormone). This is the hormone that acts directly on the thyroid gland. It is the thyroid gland that produces the actual thyroid hormone, T4 (thyroxine). The negative feedback process is best understood from the blood: if the thyroid hormone level in the blood is high, i.e. there is a lot of it, the thyroid gland will receive a signal to reduce hormone production. The thyroid sends a signal to the pituitary to reduce TSH production, and then the pituitary sends a signal to the hypothalamus. The mitochondria carry out the biological oxidation process.

The amount of any hormone, a lesion in any of the organs involved, or a feedback failure can be at the root of the thyroid disease that has developed.

For example, in Graves' disease, there is no negative feedback: even though there is a lot of hormone in the blood, the signal does not affect the organs. TSH will be low because it tries to send less signal to the thyroid, but it still continues to produce hormones, leading to overactivity.

In the case of hypothyroidism, TSH levels are usually high because the thyroid needs to be kept stimulated at a high level to produce enough hormones even when it is low.

Detailed descriptions of the diseases can be found under their individual headings.

The thyroid gland and calcium levels