Thyroid Disorders

Thyroid Disorders

Defining thyroid disorders

When the butterfly-shaped gland at the base of the front of the neck does not function as it should or structurally alters due to a disorder, a variety of different impairments and ailments can occur. This gland, the thyroid gland, functions as an important regulator for various metabolic processes and forms part of an intricate network known as the endocrine system that is essential for the body.

The role of the thyroid

Illustration of the thyroid gland.Just beneath the Adam’s apple at the base of the neck, the thyroid gland ‘wraps’ around the windpipe (or trachea). A thin portion of tissue is located at the centre of the gland (known as the isthmus) and is joined on either side by a pair of thyroid lobes.

The chemical, iodine is used by the thyroid to produce hormones that are vital for bodily function. The primary hormone that is produced by the thyroid gland is thyroxine (or T4). Once produced, the hormone is delivered to the body through the bloodstream to ‘feed’ the body’s tissues. A small portion of this hormone is also converted to triiodothyronine (or T3), a very active hormone which affects virtually every physiological process of the body – metabolism, body temperature, heart rate, growth and development.

The thyroid gland functions according to a feedback mechanism in the brain (the hypothalamus region) which helps to regulate its necessary processes. Low levels of thyroid hormones in the body signal the hypothalamus to produce the thyroptropin releasing hormone (TRH), which then prompts the pituitary gland (situated at the base of the brain), known as ‘the master gland’, to secrete thyroid stimulating hormone (TSH). The release of TSH in turn stimulates the thyroid gland to secrete its hormone (T4). The hypothalamus and pituitary gland work to prevent over- or underproduction of thyroid hormones.

The pituitary or ‘master gland’ is able to sense the amount of a particular hormone in the blood, and adjust hormone production according to how much or how little there is. Elevated levels of thyroid hormone in the bloodstream may prompt the pituitary gland to secrete less TRH and TSH. This will effectively reduce the production of thyroid hormone from the gland in order to create a healthier balance in the body. Adequate amounts of dietary iodine are also needed in order for the thyroid gland to effectively produce T3 and T4 for effective function.

A glitch in these functions can lead to disorders of the participating tissues – the hypothalamus, pituitary gland and / or the thyroid gland. Any disorder that affects the hypothalamus or pituitary gland in the brain has a direct impact on the function of the thyroid gland too.

As a result, disorders affecting the function or structure of the thyroid gland range from fairly harmless to life-threatening. The most common of the numerous thyroid problems involve irregularities in the production of hormones (either too much or too little). The majority of problems related to the thyroid gland can be well managed and treated if effectively diagnosed.

Illustration showing the human endocrine system (thyroid hormones).


Did you know? 25 May is World Thyroid Day and was launched in 2008 by the European Thyroid association (ETA) to raise awareness about the thyroid gland and its various associated disorders. This global awareness day was selected to coincide with the anniversary of the founding of the ETA (in 1965).

 

World Thyroid Day illustration

NEXT Common types and underlying causes of thyroid disorders