Thyroid Gland

The thyroid gland is a butterfly shaped endocrine gland that is located in the neck, right under the Adam's Apple. It secretes thyroid hormones which are responsible for metabolic rate and protein synthesis as well as many other physical effects. The most visible effect that the thyroid gland has is on body weight.

Hyperthroidism (too much thyroid hormone) can cause a person to be extremely thin due to an extra-high metabolism and is frequently associated with Graves' Disease, an autoimmune disorder. The reverse of this is hypothyroidism (too little thyroid hormone) that causes a person to gain weight and to have trouble losing weight.

Sometimes untreated sufferers of hypothyroidism can develop a goiter which is an enlargement of the thyroid gland that causes bulging at the neck. Hypothyroidism is easily and cheaply treated using synthetic hormones. Thyroid hormones are responsible for physical development and is secondary only to iodine deficiency as a cause for preventable intellectual disability. The problem of iodine deficiency in some geographical areas is the reason behind the addition of iodine to table salt.