- 1 The thyroid gland
- 2 Your pituitary and thyroid glands
- 3 Goitre
- 4 Other thyroid gland disorders
- 5 Thyroid hormones and metabolism
- 6 Hyperthyroidism – overactive thyroid
- 7 Hypothyroidism – underactive thyroid
The thyroid gland
What is the thyroid gland?
The thyroid gland is a key part of the human endocrine system and works together with your nervous and immune systems to regulate your body’s metabolism.
Metabolism refers to all of the processes that go on inside your body, for example, the process of turning food into energy.
The thyroid gland regulates metabolism by producing and secreting hormones into your bloodstream.
Terms explained Autoimmune disorder – a condition where your own antibodies attack your body.
Where is the thyroid gland?
The thyroid gland is located in the lower front part of your throat, just below your Adam’s apple. It consists of 2 lobes on either side of your windpipe.
What does the thyroid gland do?
Your thyroid produces 2 important hormones:
- Thyroxine, known as T4
- tri-iodothyronine, known as T3
Thyroid hormones affect your:
- body temperature and circulation
- energy levels
- growth and bone development
- muscle tone and suppleness
- heart rate
- blood sugar levels
- central nervous system and bowel function
- cholesterol levels
- fat, carbohydrate and protein metabolism.
The higher the T3 and T4 iodine count that circulates in your blood the faster your metabolism is. If you have less T3 and T4, your metabolism levels drop.
- disruption of your entire metabolic system
- unusually high or low levels of hormones or enzymes
- malfunctioning hormones or enzymes
- a build-up of toxic substances in your body
- diseases and serious health conditions.
Your pituitary and thyroid glands
The pituitary is an endocrine gland located at the base of your brain that controls your endocrine system, including your thyroid. The pituitary affects the thyroid by producing a hormone called thyroid stimulating hormone (TSH).
TSH causes cells within your thyroid to make more T3 and T4 hormone.
If there is too much T4 in your bloodstream your pituitary produces less TSH, which causes your thyroid activity to slow. If there is not enough T4 hormone the pituitary increases the amount of TSH to help speed up your metabolism.
A goitre is when your thyroid gland becomes significantly swollen and enlarged – this can happen if your diet is low in iodine.
If you are iodine deficient your pituitary gland may try to compensate by overstimulating your thyroid to produce more thyroid hormone. When this happens your thyroid grows larger and larger.
The presence of goitre in your neck suggests your thyroid is not functioning properly or you are iodine deficient.
Other thyroid gland disorders
Several disorders are associated with the thyroid gland:
- Graves’ disease
- Hashimoto’s disease
- thyroid cancer
- thyroid nodules
- congenital thyroid disease
- iodine deficiency disorder.
Thyroid hormones and metabolism
Your thyroid controls the chemical metabolic processes constantly taking place inside your body. This process of metabolism is how your body gets the energy it needs to survive and has a vital function.
Your body needs iodine to make thyroid hormones. Most people get suitable amounts of iodine from their diet as it is found in most food, especially seafood. Small amounts of iodine are found in vegetables grown in soils containing iodine.
If your thyroid cannot produce a sufficient amount of hormones you are vulnerable to a range of serious health conditions.
Hyperthyroidism – overactive thyroid
Hyperthyroidism is a condition where your thyroid is overactive and releases too many T4 and T3 hormones into your bloodstream, creating a hormonal imbalance and causing your metabolism to speed up.
The most common cause of hyperthyroidism is an autoimmune condition called Graves’ disease.
Hypothyroidism – underactive thyroid
Hypothyroidism is a condition where your thyroid is underactive and releases too little T4 and T3 hormones into your bloodstream.
This causes your metabolism to slow down too much and reduces the thyroid’s ability to make hormones.
The most common cause of hypothyroidism is an autoimmune condition called Hashimoto’s disease.