Basics of thyroid

What is Thyroid?

Thyroid is a butterfly shaped gland situated in front of the neck, normally not visible unless in a very thin individual. The function of the thyroid gland is to produce thyroid hormone. The thyroid gland is controlled by another gland called as the pituitary, which is the “master” endocrine gland. Pituitary produces TSH ( thyroid stimulating hormone) which stimulates the thyroid gland to produce the thyroid hormones. This loops maintains the balance.

What are the functions of the thyroid hormones?

Thyroid hormone has a number of effects on body’s function. The main one being to control the metabolic rate, i.e., the amount of energy used by the body to maintain vital processes such as breathing, circulation and digestion. Too much thyroid hormone makes the body to work too fast, whereas too little allows the body to slow down. Thyroid hormone also has important function of being involved in the maturation of brain and physical growth in babies both before and after birth. Deficiency of thyroid hormone certainly can affect height in the growing children.

Under-active thyroid – Thyroid gland is unable to provide normal amount of thyroid hormone.

Over-active thyroid. If the gland produces more thyroid hormone than normal, it is called over-active thyroid.

HYPO – Underactive
HYPER – Overactive

Overactive – Hyperthyroidism

Underactive – Hypothyroidism

Irritable/ Excitable

Weight loss/ Weakness


Rapid heart rate

Feeling too warm

Hyperactivity in children

Slow/ Sleepy

Weight gain/ Fluid retention

Dry skin/ Hair loss

Constipation/ Slow heart rate

Feeling too cold

Poor growth in children

Who is at risk of developing Thyroid disease?

Family history of thyroid is the main risk factor. If you have a family history and you have symptoms suggestive of under- or overactive thyroid, it is worth seeing your doctor for a physical examination and blood test. Remember thyroid disease is 10 times more common in women than in men.

What is Goitre?

Enlargement of thyroid gland is called goitre. As such this does not mean much, we need to find why the gland is big and how is it working. If we suspect that something can be wrong, we may go ahead with a small biopsy, called FNAC (fine needle aspiration cytology), to see how the cells look under the microscope.