MARCADORES BIOQUÍMICOS DAS DISFUNÇÕES DA TIREÓIDE

The video presents, in a very clear and concise way, an update and review of thyroid diseases and the main biochemical tests available in clinical practice for evaluating these dysfunctions. The lesson summarizes some aspects of thyroid physiology and the synthesis of thyroid hormones. The two thyroid hormones are: T4: Thyroxine (also called tetraiodothyronine) T3: Triiodothyronine T4, the main hormone produced by the thyroid, has only a slight effect on the speed of the body's metabolic rate. On the other hand, T4 is converted into T3, the more active hormone. The conversion of T4 to T3 occurs in the liver and other tissues. Many factors control the conversion of T4 to T3, including the body's needs at any given time and the presence or absence of disease. Most of the T4 and T3 in the bloodstream is transported bound to a protein called thyroxine-binding globulin. Only a small portion of T4 and T3 circulates freely in the blood. However, it is this free hormone that is active. When the free hormone is used by the body, some of the binding hormones are released from the binding protein. The thyroid gland needs iodine, an element found in food and water, to produce thyroid hormones. The thyroid gland concentrates iodine and transforms it into thyroid hormones. When thyroid hormones are used, some of the iodine contained in the hormones is released, returns to the thyroid gland, and is recycled to produce more thyroid hormones. More specifically, the thyroid gland releases a slightly smaller amount of thyroid hormones if it is exposed to high levels of iodine transported to it in the blood. The thyroid gland also produces the hormone calcitonin, which can contribute to bone strengthening by helping calcium to be incorporated into bone. The aspects related to hormone transport and the main proteins involved in this transport are presented. Approximately 70 to 80% of thyroid hormones secreted into the bloodstream circulate bound to a specific protein called thyroid hormone-binding globulin (TBG). Other plasma proteins such as transthyretin and albumin transport the remainder of T4 and T3. Lipoproteins also have a limited capacity to transport these hormones. The lesson also covers the main thyroid disorders such as hypothyroidism, hyperthyroidism, euthyroidism, goiter, and thyroid cancer. Hypothyroidism is an underactive thyroid gland that results in inadequate production of thyroid hormones and reduced vital bodily functions. Hyperthyroidism is a condition in which the thyroid gland is overactive and produces excess thyroid hormones. Euthyroidism occurs when there is some alteration in the thyroid gland but serum concentrations of thyroid hormones are normal. Goiter is an enlargement of the thyroid gland, usually caused by iodine deficiency or hyperthyroidism. The presence of nodules in the thyroid is also considered goiter. #thyroid, #hormones, #biochemistry