What's inside your neck?

A couple of weeks back, I took my dad for a complete health check-up. One of the doctors had scribbled something in a piece of paper and asked my dad to undergo the mentioned tests. The prescription says "T3,T4,TSH". I enquired the doctor to give some details and she told that these tests are related to thyroid gland.

Thyroid gland is the biggest gland in the neck. It is located in the front side of the neck. It's main function is to generate thyroid hormone. This hormone has an effect on all tissues of the body where it increases cellular activity, thereby regulating the body's metabolism (conversion of oxygen and calories to energy).

The function of the thyroid gland is to take iodine, found in many foods, and convert it into thyroid hormones:
Thyroxine (T4)
Triiodothyronine (T3)

Thyroid cells are the only cells in the body which can absorb iodine. These cells combine iodine and the amino acid tyrosine to make T3 and T4. T3 and T4 are then released into the blood stream and are transported throughout the body where they control metabolism.

The thyroid gland is under the control of the pituitary gland, located at the base of the brain. When the level of thyroid hormones (T3 & T4) drops too low, the pituitary gland produces Thyroid Stimulating Hormone (TSH) which stimulates the thyroid gland to produce more hormones. Under the influence of TSH, the thyroid will manufacture and secrete T3 and T4 thereby raising their levels. The pituitary senses this and responds by decreasing its TSH production.

The pituitary gland itself is regulated by another gland, known as the hypothalamus. The hypothalamus is part of the brain and produces TSH Releasing Hormone (TRH) which tells the pituitary gland to stimulate the thyroid gland (release TSH).

Common thyroid problems are related to the production of the hormone (too much, too little), increased growth of the thyroid resulting in a mass at the neck region or formation of nodules or lumps within the thyroid which might lead to thyroid cancer.

Hyperthyroidism - too much thyroid hormone. Symptoms are - weight loss, increase in body temperature, insomnia and irregular heartbeats. Methods used for treating a hyperthyroid patient are radio-active iodine, anti-thyroid drugs and surgery.

Hypothyroidism - too little thyroid hormone. A very common problem. Symptoms are - weakness, fatigue, weight gain, muscle cramps, depression and memory loss. A simple method for treating a hypothyroid patient is to prescribe a thyroid pill to be taken every morning. The dosage should be evaluated monthly.