However, while the nervous system uses nerve impulses and neurotransmitters for communication, the endocrine system uses chemical messengers called hormones.

Endocrine system function

The endocrine system is responsible for regulating a range of bodily functions through the release of hormones.

Hormones are secreted by the endocrine system glands, travelling through the bloodstream to various organs and tissues in the body. The hormones then tell these organs and tissues what to do or how to function.

For examples, some of the bodily functions that are controlled by the endocrine system include:

  • metabolism
  • sexual function and reproduction
  • growth and development
  • heart rate
  • body temperature
  • blood pressure
  • appetite
  • sleeping and waking cycles

Endocrine system organs

The endocrine system comprises a complex network of glands, which are organs that secrete substances.

The glands of the endocrine system are where hormones are produced, stored, and released. Similarly, each gland produces one or more hormones, which target specific organs and tissues in the body.

The glands of the endocrine system include:

  • Hypothalamus. While some people don’t consider it a gland, the hypothalamus produces multiple hormones that control the pituitary gland. It’s also involved in regulating many functions, including sleep-wake cycles, body temperature, and appetite. It can also regulate the function of other endocrine glands.
  • Pituitary. The pituitary gland is located below the hypothalamus. The hormones it produces affect growth and reproduction. They can also control the function of other endocrine glands.
  • Pineal. This gland is found in the middle of your brain. It’s important for your sleep-wake cycles.
  • Thyroid. The thyroid gland is located in the front part of your neck. It’s essential for metabolism.
  • Parathyroid. Also located in the front of your neck, the parathyroid gland is important for maintaining calcium levels in your bones and blood.
  • Thymus. Located in the upper torso, the thymus is active until puberty and produces hormones important for developing a type of white blood cell called a T cell.
  • Adrenal. One adrenal gland can be found on top of each kidney. These glands produce hormones important for regulating blood pressure, heart rate, and stress response.
  • Pancreas. The pancreas is located in your abdomen behind your stomach. Its endocrine function involves controlling blood sugar levels.

Although, some endocrine glands also have non-endocrine functions. For example, the ovaries and testes produce hormones, but they also have the non-endocrine function of producing eggs and sperm, respectively.

Due hormones are the chemicals the endocrine system uses to send messages to organs and tissue throughout the body. Once released into the bloodstream, they travel to their target organ or tissue, which has receptors recognising and reacting to the hormone.

Below are some examples of hormones that are produced by the endocrine system.

Hormone Secreting gland(s) Function
adrenaline adrenal increases blood pressure, heart rate, and metabolism in reaction to stress
aldosterone adrenal controls the body’s salt and water balance
cortisol adrenal plays a role in stress response
dehydroepiandrosterone sulfate (DHEA) adrenal aids in the production of body odour and growth of body hair during puberty
estrogen ovary works to regulate the menstrual cycle, maintain pregnancy, and develop female sex characteristics; aids in sperm production
follicle-stimulating hormone (FSH) pituitary controls the production of eggs and sperm
glucagon pancreas helps to increase levels of blood glucose
insulin pancreas helps to reduce your blood glucose levels
luteinizing hormone (LH) pituitary controls estrogen and testosterone production as well as ovulation
melatonin pituitary controls sleep and wake cycles
oxytocin pituitary helps with lactation, childbirth, and mother-child bonding
parathyroid hormone parathyroid controls calcium levels in bones and blood
progesterone ovary helps to prepare the body for pregnancy when an egg is fertilized
prolactin pituitary promotes breast-milk production
testosterone ovary, teste, adrenal contributes to sex drive and body density in males and females as well as the development of male sex characteristics
thyroid hormone thyroid help to control several body functions, including the rate of metabolism and energy levels

What are the conditions that can affect the endocrine system?

 

Oftentimes, hormone levels can be too high or too low. When this happens, it can have several effects on your health. The signs and symptoms depend on the hormone that’s out of balance.

Here’s a look at some conditions that can affect the endocrine system and alter your hormone levels.

Hyperthyroidism

Hyperthyroidism happens when your thyroid gland makes more thyroid hormone than necessary. This can be caused by a range of things, including autoimmune conditions.

Some common symptoms of hyperthyroidism include:

  • nervousness
  • weight loss
  • diarrhoea
  • issues tolerating heat
  • fatigue
  • fast heart rate
  • trouble sleeping

Treatment depends on how severe the condition is, as well as its underlying cause. Options include medications, radioiodine therapy, or surgery.

Graves disease is an autoimmune disorder and a common form of hyperthyroidism. In people with Graves disease, the immune system attacks the thyroid, which causes it to produce more thyroid hormone than normal.

Hypothyroidism

Hypothyroidism occurs when your thyroid doesn’t produce enough thyroid hormone. Like hyperthyroidism, it has many potential causes.

Some common symptoms of hypothyroidism include:

  • fatigue
  • weight gain
  • constipation
  • issues tolerating the cold
  • dry skin and hair
  • slow heart rate
  • irregular periods
  • fertility issues

Treatment of hypothyroidism involves supplementing your thyroid hormone with medication.

Cushing syndrome

Cushing syndrome happens due to high levels of the hormone cortisol.

Common symptoms of Cushing syndrome include:

  • weight gain
  • fatty deposits in the face, midsection, or shoulders
  • stretch marks, particularly on the arms, thighs, and abdomen
  • slow healing of cuts, scrapes, and insect bites
  • thin skin that bruises easily
  • irregular periods
  • decreased sex drive and fertility in males

Treatment depends on the cause of the condition and can include medications, radiation therapy, or surgery.

Addison disease

Addison disease happens when your adrenal glands don’t produce enough cortisol or aldosterone. Some symptoms of Addison disease include:

  • fatigue
  • weight loss
  • abdominal pain
  • low blood sugar
  • nausea or vomiting
  • diarrhoea
  • irritability
  • a craving for salt or salty foods
  • irregular periods

Treatment of Addison disease involves taking medications that help replace the hormones that your body isn’t producing enough.

Diabetes

Diabetes refers to a condition in which your blood sugar levels aren’t regulated properly.

People with diabetes have too much glucose in their blood (high blood sugar). There are two types of diabetes: type 1 diabetes and type 2 diabetes.

Some common symptoms of diabetes include:

  • fatigue
  • weight loss
  • increased hunger or thirst
  • frequent urge to urinate
  • irritability
  • frequent infections

Diabetes treatment can include blood sugar monitoring, insulin therapy, and medications. Lifestyle changes, such as getting regular exercise and eating a balanced diet, can also help.