Hypothyroidism Essay

775 Words2 Pages

Hypothyroidism

Hypothyroidism is a chronic disease that is part of the endocrine system. Hypothyroidism is due low or lack of tri-iodothryonine (T3) and tetraiodothyronine (T4) thyroid hormones being produced by the thyroid gland. The lack of thyroid hormones could be due to iodine or thyroid stimulating hormone (TSH) deficiency or underactive thyroid gland (Sherwood, 2012). Thyroid hormones T3 and T4 are involved in almost every part of the body. It is ten times more prevalent in female than male, which affects about 4.6% of U.S population (Lellis-Santos et al, 2011). In the most cases, the symptoms are cold intolerance, fatigue, bradycardia and weight gain. Depending on the cause on hypothyroidism, a goiter may develop, which is the enlargement of the thyroid gland. In most cases taking thyroid hormone supplement is an effective treatment.
In healthy an individual, the thyroid gland produces thyroid hormones T3 and T4 through a series of steps. Iodide is carry into the thyroid follicular cell from the blood stream by symporters. The iodide is transported into the cell against it concentration gradient, using Na+ concentration gradient as an energy source. The iodide in the follicular cell is activated through oxidation by thyroperoxidase (TPO). The active iodide is passively transported into the colloid through an iodide channel on the luminal side of the follicular cell down its concentration gradient. Thyroglobulin (Tg) another precursor of thyroid hormone enters the colloid via exocytosis from the Golgi complex of the follicular cell. The Thyroglobulin (Tg) binds to iodide with the help of thyroperoxidase forming monoiodotyrosine (MIT). If another iodide is added to the tyrosine reside of Tg, di-iodotyrosine is formed (DIT...

... middle of paper ...

...wn. Thus they stored instead. As a result people with low levels of thyroid hormones undergo weight gain. Also due to decrease in metabolism of fat, there is a decreased in heat production thus leading to cold intolerance as well.
Another effect of the deficiency of thyroid hormones is bradycardia. Thyroid hormones play an important role in regulating cardiac activity. T3 binds thyroid hormone receptor alpha in the nucleus of the cell. The T3-TRalpha binds to the thyroid hormone response element, which activates the gene for production of myosin (CITE Hormone ACTIOn). Myosin is a cytoskeleton protein that is important for contractibility of the heart. With low levels of thyroid hormones, the myosin heavy chain-beta gene is not expressed, resulting in decreasing contractility of the heart. Thus those with hypothyroidism tend to have slower heart rate or bradycardia.

More about Hypothyroidism Essay

Open Document