What is the thyroid?

Thyroid

Your thyroid is an important endocrine gland that makes and releases certain hormones. Your thyroid's main job is to control your metabolism — how your body uses energy. Sometimes, your thyroid doesn’t work properly. These conditions are common and treatable.

What is the thyroid?

Your thyroid is a small, butterfly-shaped gland located at the front of your neck under your skin. It’s a part of your endocrine system and controls many of your body’s important functions by producing and releasing (secreting) certain hormones. Your thyroid’s main job is to control the speed of your metabolism (metabolic rate), which is the process of how your body transforms the food you consume into energy. All of the cells in your body need energy to function.

When your thyroid isn’t working properly, it can impact your entire body.

What is the endocrine system?

Your endocrine system is a network of several glands that create and secrete (release) hormones.

A gland is an organ that makes one or more substances, such as hormones, digestive juices, sweat or tears. Endocrine glands release hormones directly into the bloodstream.

Hormones are chemicals that coordinate different functions in your body by carrying messages through your blood to your organs, skin, muscles and other tissues. These signals tell your body what to do and when to do it.

The following organs and glands make up your endocrine system:

• Hypothalamus.
• Pituitary gland.
• Thyroid.
• Parathyroid glands.
• Adrenal glands.
• Pineal gland.
• Pancreas.
• Ovaries.
• Testes.

Function

What does my thyroid do?

As an endocrine gland, your thyroid makes and secretes hormones. Your thyroid produces and releases the following hormones:

• Thyroxine (T4): This is the primary hormone your thyroid makes and releases. Although your thyroid makes the most of this hormone, it doesn’t have much of an effect on your metabolism. Once your thyroid releases T4 into your bloodstream, it can convert to T3 through a process called deiodination.
• Triiodothyronine (T3): Your thyroid produces lesser amounts of T3 than T4, but it has a much greater effect on your metabolism than T4.
• Reverse triiodothyronine (RT3): Your thyroid makes very small amounts of RT3, which reverses the effects of T3.
• Calcitonin: This hormone helps regulate the amount of calcium in your blood.

In order to make thyroid hormones, your thyroid gland needs iodine, an element found in food (most commonly, iodized table salt) and water. Your thyroid gland traps iodine and transforms it into thyroid hormones. If you have too little or too much iodine in your body, it can affect the level of hormones your thyroid makes and releases.

Your thyroid hormones affect the following bodily functions:

• How your body uses energy (metabolism).
• Heart rate.
• Breathing.
• Digestion.
• Body temperature.
• Brain development.
• Mental activity.
• Skin and bone maintenance.
• Fertility.What other organs and 

What other organs and glands interact with the thyroid?

Your endocrine system is an elaborate network of glands and hormones. Many glands and hormones rely on other glands and hormones to send them signals to start working. In addition, certain hormones can suppress other hormones.

  

• Your cardiovascular system: Your thyroid helps regulate the amount of blood your heart pumps through your circulatory system (cardiac output), heart rate and strength and vigor of your heart's contraction (contractility of the heart).
• Your nervous system: When your thyroid isn’t working properly, it can cause symptoms that affect your nervous system, including numbness, tingling, pain or a sense of burning in the affected parts of your body. In addition, hypothyroidism can cause depression and hyperthyroidism can cause anxiety.
• Your digestive system: Your thyroid is involved with how food moves through your digestive system (gastrointestinal motility).
• Your reproductive system: If your thyroid isn’t working properly, it can cause irregular menstrual periods and issues with fertility.

Can a person live without a thyroid?

Yes, you can live without your thyroid. However, you’ll need to take hormone replacement medication for the rest of your life in order to stay healthy and prevent certain side effects and symptoms.

Conditions and Disorders

The four main conditions that affect your thyroid include:

• Hypothyroidism (underactive thyroid).
• Hyperthyroidism (overactive thyroid).
• Goiter (enlarged thyroid).
• Thyroid cancer.

Hypothyroidism

Hypothyroidism (underactive thyroid) happens when your thyroid doesn’t produce and release enough thyroid hormones.

Causes of hypothyroidism include:

• Hashimoto’s disease, an autoimmune disease.
• Thyroiditis (inflammation of the thyroid).
• Iodine deficiency.
• A nonfunctioning thyroid gland (when the thyroid doesn’t work correctly from birth).
• Over-treatment of hyperthyroidism through medication.
• Thyroid gland removal.

This causes aspects of your metabolism to speed up. Approximately 1 out of 100 people over the age of 12 have hyperthyroidism in the United States. It is treatable.

Causes of hyperthyroidism include:

• Graves’ disease, an autoimmune condition.
• Thyroid nodules.
• Thyroiditis (inflammation of the thyroid).
• Postpartum thyroiditis (inflammation of the thyroid that happens after giving birth).
• Excess iodine in your blood from diet and/or medication.
• Over-treatment of hypothyroidism through medication.
• A benign (noncancerous) tumor in your pituitary gland.

Goiter

Goiter is an enlargement of your thyroid gland. Goiters are relatively common; they affect approximately 5% of people in the United States.

Simple goiters: These goiters develop when your thyroid gland doesn’t make enough hormones to meet your body's needs.

Endemic goiters: These goiters occur in people who don't get enough iodine in their diet (iodine is necessary to make thyroid hormone).

Sporadic goiters: These goiters have no known cause in most cases. In some cases, certain medications, such as lithium, can cause sporadic goiters.

Thyroid cancer

Thyroid cancer is classified based on the type of cells from which cancer grows. Thyroid cancer types include:

• Papillary: Up to 80% of all thyroid cancer cases are papillary.
• Follicular: Follicular thyroid cancer accounts for up to 15% of thyroid cancer diagnoses.
• Medullary: About 2% of thyroid cancer cases are medullary. It’s often caused by a gene mutation.
• Anaplastic: About 2% of thyroid cancer cases are anaplastic.

What are the early warning signs and symptoms of thyroid problems?

• Slow or rapid heart rate.
• Unexplained weight loss or weight gain.
• Difficulty tolerating cold or heat.
• Depression or anxiety.
• Irregular menstrual periods.

What are common tests to check the health of the thyroid?

thyroid is a blood test that measures your levels of thyroid-stimulating hormone (TSH). It’s a screening test for both hypothyroidism and hyperthyroidism.

Your provider can also check the levels of T4 and T3 (thyroid hormones) in

your blood.

radioactive material to create images of your thyroid, or a thyroid ultrasound.

How are thyroid conditions treated?

There are several treatment options for thyroid conditions depending on what the conditions are and how severe they are. The three main options for treatment include:

• Medication.
• Surgery.
• Radiation therapy and chemotherapy.

coclusion:

The first-line test for checking the health of your thyroid is a blood test that measures your levels of thyroid-stimulating hormone (TSH). It’s a screening test for both hypothyroidism and hyperthyroidism.