The human body is a complex….. One of the various systems within the human body is the endocrine system. This system, which is composed of a group of glands, is responsible for the synthesis and secretion of chemical compounds known as hormones into the bloodstream. A major gland of the endocrine is the thyroid gland which is responsible for the synthesis of thyroxin as well as other hormones that control the body’s metabolism. The thyroid gland… Many diseases and conditions may arise and can have a profound effect on the thyroid’s physiology and function which will indubitably affect the overall health of an individual. One such condition is hypothyroidism in which the thyroid does not secrete adequate levels of its principle hormone, thyroxin. This condition can affect individuals in various ways such as…. Advances in research in the medical field over many decades have allowed for the development of a treatment for this condition in the form of synthetic replacement hormone designed to perform the same processes as the endogenous thyroxin. Levothyroxine is one of the most commonly used synthetic medicines to treat hypothyroidism in that it works to increase the thyroxin levels in the body by mimicking the action of natural thyroxin. In all, the understanding of the function and physiology of the thyroid gland has been considerably improved and cures for different thyroid diseases.

1. The endocrine system is a group of glands in the body that secrete chemical substances known as hormones directly into the circulatory system that transports them to the desired target organ. The thyroid gland is a major endocrine gland located in the lower part of the neck. The normal thyroid gland is a firm, smooth gland consisting of two lateral lobes and a connecting central isthmus. On a microscopic level, the thyroid gland entails numerous spherical hollow sacs known as thyroid follicles. These follicles are lined with a simple cuboidal epithelium composed of follicular cells that produce the principal thyroid hormone, thyroxin. The interior of the follicles contains colloid, a protein-rich fluid. The primary function of the thyroid is the synthesis and releases of the hormones triiodothyronine (T3), thyroxin (T4) and calcitonin which aid in the regulation of the body’s metabolic rate. Sufficient levels of thyroid hormone are necessary in infants for normal development of the CNS. In children for normal skeletal growth and maturation, and in adults for normal function of multiple organ systems. Most steps of thyroid hormone synthesis take place within the colloid. The thyroid captures iodide (I-) from the blood and transfers it into the colloid by an iodide pump. Once the iodide has entered the colloid, it is oxidized (reaction with Oxygen) and attached to a specific amino acid (tyrosine) within the polypeptide chain of a protein termed thyroglobulin. The structures of those tyrosines are heavily modified by enzymes in the colloid until thyroxin is eventually formed.

1. Hypothyroidism is a common endocrine