The endocrine system is the name for the glands that produce hormones in a person’s body. These glands include the thyroid gland, pituitary gland, and adrenal gland. The endocrine system produces hormones such as insulin, estrogen, testosterone, and adrenaline.

The endocrine system produces and secretes a number of hormones in the body. These hormones play a vital role in many functions.

There are several different glands that make up the endocrine system. These glands produce and send hormones into the bloodstream, where they travel to different tissues in the body.

If the glands do not function properly and produce incorrect amounts of hormones, a person can develop certain disorders of the endocrine system.

This article discusses the endocrine system, its functions, the different glands present in the system, and certain endocrine disorders and diseases.

Sex and gender exist on spectrums. For this article, we use “male” and “female” to refer to a person’s sex assigned at birth.

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Hormones are chemical messengers that enter the bloodstream and travel to specific areas of the body. These hormones then act on an organ or other cells in order to play a role in certain bodily functions.

Certain glands throughout the body make these hormones. The endocrine system is the name for this collection of glands.

The hormones that the endocrine system creates play a role in the following bodily functions:

  • respiration
  • metabolism
  • reproduction
  • sensory perception
  • movement
  • sexual development
  • growth

Hormones can travel to all areas of the body. However, they only target cells that have compatible receptors. These cells are equipped to respond to the hormone and carry out certain functions when they come in contact with the hormone.

Hormones act by binding to certain receptors within cells. When a hormone binds to a receptor, the receptor then carries out the hormone’s instructions.

Different glands within the body produce different hormones. These different hormones all have a number of varying functions.

Below is a list of different glands and organs within the endocrine system.

Hypothalamus

The hypothalamus is present in the brain. It coordinates the endocrine system and links it with the nervous system.

The hypothalamus receives signals from various parts of the brain. It then releases and inhibits hormones based on these signals.

These hormones then act on the pituitary gland, which in turn directs the actions of several other glands in the body.

The hypothalamus releases hormones that play a role in:

  • body temperature regulation
  • appetite
  • weight gain
  • mood
  • sex drive
  • sleep
  • thirst

Pituitary gland

The pituitary gland is located at the base of the brain. It is sometimes known as the “master gland” because it plays a role in so many bodily functions.

The pituitary gland releases hormones that travel throughout the body. These hormones either direct certain processes within the body or stimulate other glands to produce other hormones.

The pituitary gland produces the following hormones:

  • Prolactin: This hormone stimulates breast milk production after childbirth. High levels of prolactin can affect hormones that control the ovaries in females and the testes in males. Prolactin can affect menstrual periods, sexual functionality, and fertility.
  • Growth hormone (GH): This hormone stimulates growth in childhood. It also plays a role in maintaining healthy muscles and bones in people of all ages. GH also affects fat distribution around the body.
  • Adrenocorticotropin (ACTH): This hormone causes the adrenal gland to produce cortisol. Cortisol helps maintain blood pressure and blood sugar levels. Cortisol is sometimes known as a “stress hormone.” The body produces large amounts of it when a person is under stress.
  • Thyroid stimulating hormone (TSH): This hormone causes the thyroid gland to produce hormones that regulate the body’s metabolism, energy balance, growth, and nervous system activity.
  • Luteinizing hormone (LH): This hormone stimulates the production of testosterone in males and egg release in females.
  • Follicle stimulating hormone (FSH): This hormone stimulates the production of sperm in males. It also causes the ovaries to produce estrogen and develop eggs in females.
  • Antidiuretic hormone (ADH): This hormone is made in the hypothalamus but stored and released from the posterior pituitary gland. It regulates water balance in the body. It also regulates sodium levels in the blood. ADH can conserve water in the body by reducing the amount of water a person loses in their urine.
  • Oxytocin: This hormone causes milk to flow during breastfeeding and can help labor progress during childbirth. It is also made in the hypothalamus but stored and released from the posterior pituitary gland.

Parathyroid gland

The parathyroid gland is a group of four small glands that sits behind the thyroid gland. This gland produces the parathyroid hormone (PTH).

PTH facilitates the creation of active vitamin D in the kidneys. This helps control a person’s calcium and phosphorous levels. This makes PTH vital for bone development and health.

Pancreas

The pancreas is a gland organ that is situated in the abdomen. The main function of the pancreas is to maintain healthy blood sugar levels.

Below are the two main hormones that the pancreas produces:

  • Insulin: Insulin is a hormone that allows cells in a person’s muscles, fat, and liver to absorb glucose in the blood, preventing blood sugar levels from getting too high. This allows the glucose to provide these cells with energy. Insulin can also affect the breakdown of fat or protein.
  • Glucagon: This hormone prevents blood sugar levels from dropping too low. It causes the liver to convert stored blood sugar into a usable form before releasing it into the bloodstream. Glucagon also stops the liver from storing glucose, meaning more remains in the blood.

Thyroid

The thyroid is located in the front of a person’s neck. This gland plays an important role in controlling a person’s metabolism.

The hormones that the thyroid produces affect the way the body uses energy, consumes oxygen, and produces heat.

Adrenal gland

The adrenal glands are located at the top of both kidneys. These glands produce hormones such as:

  • glucocorticoids, including cortisol
  • mineralocorticoids
  • adrenal androgens
  • catecholamines, such as:
    • epinephrine, also known as adrenaline
    • norepinephrine

These hormones can help the body with the following functions:

  • helping maintain proper cardiovascular function
  • helping a person respond well to stressful situations
  • promoting the proper use of carbohydrates and fats
  • distributing stored fat
  • producing body odor and pubic hair
  • promoting a healthy gastrointestinal system

Pineal gland

The pineal gland is located in the brain. It produces the hormone melatonin.

Melatonin influences the rhythm of sleep by helping the body recognize when it is time to go to sleep.

Ovaries

Ovaries are present in females. They are located in the lower left and right quadrants of the abdomen.

The ovaries produce eggs as well as hormones such as:

  • estrogen
  • testosterone
  • progesterone

These hormones play a vital role in the following processes:

  • reproductive organ development
  • breast development
  • bone health
  • pregnancy
  • fertility

Testes

These glands are present in males and are situated in the scrotum.

The testes produce the hormone testosterone. Testosterone promotes the growth of the penis as the person gets older, as well as the growth of facial hair and body hair.

Testosterone also plays a role in deepening the person’s voice as they reach a certain age. It also helps:

  • maintain a person’s sex drive
  • promote the production of sperm
  • maintain muscle mass
  • maintain bone mass

When the endocrine system produces incorrect amounts of certain hormones, a person may develop different kinds of conditions. Below are some disorders of the endocrine system.

Diabetes

Diabetes is a condition where the body does not properly control the levels of sugar in the bloodstream.

Diabetes occurs when the pancreas does not produce enough insulin or the body does not effectively use the insulin that it does produce. There are different types of diabetes.

Common symptoms of diabetes include:

  • frequent urination
  • constantly feeling thirsty
  • feeling more tired than usual
  • sudden weight loss
  • blurred vision
  • increased appetite

A person can manage their diabetes with certain medications and dietary changes.

If a person does not manage their diabetes, it can lead to a number of complications, including:

  • dental and gum diseases
  • eye issues and loss of sight
  • foot problems, including numbness, leading to ulcers
  • heart disease
  • nerve damage, such as diabetic neuropathy
  • stroke
  • kidney disease

Cushing’s syndrome

Cushing’s syndrome occurs when the endocrine system produces too much of the hormone cortisol.

Common symptoms of Cushing’s syndrome include:

  • weight gain
  • thin arms and legs
  • a round face
  • increased fat at the base of the neck
  • a fatty hump that develops between the shoulders
  • bruising more easily
  • muscle weakness
  • the presence of wide, purple stretch marks, commonly on the:
    • abdomen
    • breasts
    • hips
    • under the arms

Complications of Cushing’s syndrome include:

  • heart attack
  • stroke
  • blood clots in the legs and lungs
  • infections
  • bone loss and fractures
  • high blood pressure
  • unhealthy levels of cholesterol
  • depression
  • memory loss
  • trouble concentrating
  • insulin resistance and prediabetes
  • type 2 diabetes

Adrenal insufficiency and Addison’s disease

If a person has adrenal insufficiency, then their adrenal glands do not make enough of certain hormones.

Addison’s disease is a type of adrenal deficiency. It occurs when a person’s adrenal glands are damaged and do not make enough cortisol and sometimes aldosterone.

Adrenal insufficiency can affect the way a person’s body responds to stress. It can also affect the way a person’s body maintains other functions that may be essential.

Common symptoms of adrenal insufficiency include:

  • fatigue
  • muscle weakness
  • loss of appetite
  • weight loss
  • abdominal pain

If a person has adrenal insufficiency, the correct treatment can help them to lead an active, typical life.

Overactive thyroid

If a person has an overactive thyroid, then their thyroid gland produces too many hormones.

Hyperthyroidism is another name for an overactive thyroid. By producing too much of certain hormones, an overactive thyroid can cause symptoms such as:

  • nervousness
  • irritability
  • the inability to relax
  • feeling warm
  • heat intolerance
  • sweating
  • heart palpitations
  • fatigue
  • increased frequency of bowel movements
  • increased appetite
  • weight loss

There are several possible causes of an overactive thyroid, including:

  • an autoimmune thyroid disease
  • a toxic thyroid nodule
  • thyroid inflammation
  • the use of certain drugs to treat other conditions

With the right treatment, a person can live a typical life. However, without treatment, an overactive thyroid can cause a number of complications. These include heart dysfunction and heart failure, strokes, and osteoporosis.

Other endocrine system disorders

Other endocrine system disorders include:

If a person believes they may have an endocrine disorder, they should speak with a doctor. An accurate diagnosis can help a person begin treatment, which may improve symptoms.

Often, treatment for an endocrine disorder can reduce a person’s risk of developing complications associated with that disorder.

The endocrine system is the name for the glands in the body that produce hormones. These glands include the thyroid gland, pituitary gland, and adrenal gland.

The endocrine system produces hormones, including insulin, estrogen, testosterone, and adrenaline.

These hormones play a role in a number of functions, including respiration, metabolism, reproduction, sensory perception, sexual development, and growth.

If the glands do not function properly, then they may produce incorrect amounts of hormones. This can cause a person to develop certain endocrine system disorders.

Examples of endocrine system disorders include diabetes, hyperactive thyroid, adrenal insufficiency, and Cushing’s syndrome.