The thyroid gland.

by courterney (student)

Thyroid

The Thyroid or Thyroid gland is one of the largest endocrine glands in the body. The endocrine system is the system that secretes hormones and regulates the body. The thyroid is located in the lower front part of the neck, near the trachea and below the larynx. It comprises of two lobes connected together by the band of tissue called the isthmus.

The thyroid weighs about 18-60 grams and is very light and is larger in men than women but it is bigger in women when pregnant. It looks like a butterfly or bowtie.

The thyroid is an important part of the body and it is especially important to teenagers. The thyroid manufactures the hormone that helps control metabolism and growth. To do this the thyroid needs the chemical element called Iodine, there is about 50 milligrams of iodine in our body.

Thyroid hormones are released from the gland and travel through the bloodstream to your body's cells. They help control growth and the structure of bones, sexual development and many other body functions. Hormones are important in determining if your body will mature as it should. Thyroid hormones also directly affect how most of your organ's function. So when the thyroid isn't working properly, you can have problems in lots of other parts of your body.

The thyroid gland is composed of specialized sacs referred to as follicles. The thyroid follicles are spherical in shape. The cells of the follicles have one function which is to produce thyroglobulin, a precursor to true thyroid hormones. When the thyroid is not secreting hormones, the sacs are filled with thyroglobulin. When the body requires thyroid hormones, the thyroglobulin is broken down to produce the hormones which are secreted into the bloodstream.

The thyroid gland is controlled by the pituitary gland in the brain. The pituitary gland affects the thyroid gland by producing a hormone called thyroid-stimulating hormone (TSH) which prompts the thyroid to release more thyroxine (T4) and tri-iodothyronine (T3).

Disorders:

Hyperthyroidism: Hyperthyroidism is an overactive thyroid. It is when the overproduction of the thyroid hormones thyroxine and tri-iodothyronine by the thyroid gland to which hyperthyroidism refers. The most common cause of hyperthyroidism is a disease called "Graves' Disease." The thyroid enlarges as a result of the thyroid glands overproduction of the hormones.

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Disorders:

Graves' disease is an considered to be an autoimmune disease and is the most common cause of thyroid gland over activity. Graves' disease is much more common in women than in men. Graves' Disease results from excess stimulation of the thyroid gland and usually presents with symptoms in the 2-3rd decade of life. Symptoms include: An enlarged thyroid, protruding eyes, palpitations, excess sweating, diarrhea, weight loss, muscle weakness and unusual sensitivity to heat. Treatments of Grave's disease can involve- Taking a thyroid suppressant or the patient taking an oral dose of radioactive iodine, resulting in permanent destruction of cells in the thyroid, thus rendering them permanently inactive the patient may then be treated with daily replacement hormone therapy as a result of a new found hypothyroidism or surgically removing part or the whole thyroid.

Hypothyroidism: Hypothyroidism is the underproduction of the hormones thyroxine and tri-iodothyronine. Hypothyroidism disorder occurs when the thyroid gland is inactive or underactive as a result of improper formation from birth or the removal in whole or removal of part of the thyroid gland.

Symptoms include: abnormal weight gain, tiredness, baldness, temperature intolerance (both hot and cold) and palpitations.

Initial Hyperthyroidism followed by hypothyroidism: This is the overproduction of thyroxine and tri-iodothyronine followed by the underproduction of these hormones.

There are two types: Hashimoto's Thyroiditis and Postpartum Thyroiditis.

Hashimoto's Thyroiditis: is an autoimmune disorder whereby the body's own immune system reacts with the thyroid tissues. At the beginning, the gland is overactive, and then becomes underactive as the gland is destroyed resulting in too little thyroid hormone production or hypothyroidism. Hashimoto's is most common in middle-age females and tends to run in families.

Postpartum Thyroiditis: occurs in some females following delivery. The gland gets inflamed and the condition initially presents with over activity of the gland followed by under activity. In some cases, the gland does recover with time and resume its functions.

Enlargement of the thyroid: An enlarged thyroid gland can exist and not be considered hyperthyroidism. The term Non-toxic goiter is used when enlargement of the thyroid gland occurs-but only if the enlargement is not as a result of hyperthyroidism (not due to the overproduction of a thyroid hormone), nor due to a malignancy. Only then can the condition be deemed a "Non-toxic Goiter." This enlargement can occur when iodine is not in the diet in sufficient amounts

Additionally, enlargement of the thyroid can also occur as a result of a bacterial infection or a viral infection. When this occurs it is deemed 'Thyroiditis'.

Cancers: Cancers do occur in the thyroid gland and, in general, are more common in females. In most cases, the thyroid cancer presents as a painless mass in the neck. It is very unusual for the thyroid cancers to present with symptoms, unless it has been neglected. One may be able to feel a hard nodule in the neck. Diagnosis is made using a needle biopsy and various radiological studies. All thyroid cancers are treated with surgery.

Non-cancerous nodules: Many individuals may find the presence of small masses (nodules) in the neck. The majority of these thyroid nodules are benign (non cancerous). The presence of a thyroid nodule does not mean one has thyroid disease. Most thyroid nodules do not cause any symptoms, and most are discovered on an incidental exam. Doctors usually perform a needle aspiration biopsy of the thyroid to determine the status of the nodules. If the nodule is found to be non-cancerous, no other treatment is required. If the nodule is suspicious then surgery is recommended.

Seasonal Aggravation: Limited research shows that seasonal allergies may trigger episodes of hypo- or hyperthyroidism.

My Model

Stages of Process:

1. I cut chicken wire to hold model up and stuck newspaper in the make it solid.

2. I then plastered play dough around the model making the trachea (wind pipe) and larynx (voice box).

3. Then after that process had been completed I proceeded to make the Thyroid out of pink play dough and wrapped it around the trachea where it is located under the larynx. Then after that I punched holes into the play dough for the follicles.

4. Then I put the blue play dough to make rings around the trachea to make it look more realistic.

5. Then lastly I created the Carotid artery, superior thyroid arteries and the Interior thyroid arteries which have wire in them to stay upright.

Problems encountered: I didn't have enough play dough to start off with and had to make some which was really soft and hard to mould, it also turned very dry and nothing would stick to it making it very hard to make and keep up right. The thyroid kept falling off the trachea and the arteries would not stick on and it was very time consuming in the end I had to put wire in the arteries to stick them in but still could not get them to keep their shape so I had to end up laying the model down. The end model was not what I had expected it to turn up right with all the problems encountered during the process.