Endocrine System: What Is It, Functions, Organs & Conditions (2023)

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

Hormones are secreted by the glands of the endocrine system, traveling 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.

Some examples of bodily functions that are controlled by the endocrine system include:

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

What is a gland?

A gland is an organ that creates and releases substances that the body needs to function. There are two types of glands:

  • endocrine glands, which release hormones directly into the bloodstream
  • exocrine glands, like lymph nodes and sweat glands, which are not part of the endocrine system

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

The glands of the endocrine system include the:

(Video) The Endocrine system: Functions, Organs.

  • 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 very important for metabolism.
  • Parathyroid. Also located in the front of your neck, the parathyroid gland is important for maintaining control of calcium levels in your bones and blood.
  • Thymus. Located in the upper torso, the thymus is active until puberty and produces hormones that are important for the development of 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 that are important for regulating functions such as 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.

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.

Hormones are the chemicals the endocrine system uses to send messages to organs and tissue throughout the body. Once released into the bloodstream, hormones travel to their target organ or tissue, which has receptors that recognize and react to the hormone.

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

HormoneSecreting gland(s)Function
adrenalineadrenalincreases blood pressure, heart rate, and metabolism in reaction to stress
aldosteroneadrenalcontrols the body’s salt and water balance
cortisoladrenalplays a role in stress response
dehydroepiandrosterone sulfate (DHEA-S)adrenalaids in production of body odor and growth of body hair during puberty
estrogenovaryworks to regulate the menstrual cycle, maintain pregnancy, and develop female sex characteristics; aids in sperm production
follicle-stimulating hormone (FSH)pituitarycontrols the production of eggs and sperm
glucagonpancreashelps increase levels of blood glucose (blood sugar)
insulinpancreashelps reduce your blood glucose levels
luteinizing hormone (LH)pituitarycontrols estrogen and testosterone production as well as ovulation
melatoninpinealcontrols sleep-wake cycles
oxytocinpituitaryhelps with lactation, childbirth, and mother-child bonding
parathyroid hormoneparathyroidcontrols calcium levels in bones and blood
progesteroneovaryhelps prepare the body for pregnancy when an egg is fertilized
prolactinpituitarypromotes breast-milk production
testosteroneovary, teste, adrenalcontributes to sex drive and body density in males and females as well as development of male sex characteristics
thyroid hormonethyroidhelps control several body functions, including the rate of metabolism and energy levels

Explore the interactive 3-D diagram below to learn more about the endocrine system.

(Video) Endocrine System: What Is It, Functions & Organs | Video for Kids

Sometimes, hormone levels can be too high or too low. When this happens, it can have a number of 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 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:

  • fatigue
  • nervousness
  • weight loss
  • diarrhea
  • issues tolerating heat
  • 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 usual.


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

Some common symptoms of hypothyroidism include:

(Video) Endocrine System, Part 1 - Glands & Hormones: Crash Course Anatomy & Physiology #23

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

Treatment for 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’s disease

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

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

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


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

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
  • increased hunger or thirst
  • frequent urge to urinate
  • irritability
  • frequent infections

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

Polycystic ovary syndrome (PCOS)

This common condition is caused by unbalanced reproductive hormones in people with ovaries, which can create issues in the ovaries. Living with PCOS can mean that an egg may not be released every month, or may not develop as it should when it is released.

(Video) Endocrine gland hormone review | Endocrine system physiology | NCLEX-RN | Khan Academy

Some of the common symptoms of PCOS are:

  • irregular periods
  • fertility issues
  • cysts that form on the ovaries
  • acne
  • hirsutism, which is an unusual amount of hair growth on the face or chin
  • thinning hair
  • weight gain
  • skin tags

Treatment for PCOS focuses on easing the symptoms. Treatments include medications, like birth control and metformin, and lifestyle changes, such as focusing on nutrition and trying to reach a moderate weight if your doctor has recommended it.


A common condition, especially in older males and occasionally in females, hypogonadism is caused by a lowered production of the sex hormone testosterone. This can lead to lowered libido, as well as a variety of other symptoms, such as:

  • erectile dysfunction in people with a penis
  • reduced energy
  • reduced muscle mass
  • depressed mood
  • increased irritability

Treatment for hypogonadism focuses on improved testosterone levels. Testosterone replacement therapy and lifestyle changes (such as working toward a moderate weight if your doctor has recommended it) are two popular methods.


Osteoporosis is an abnormal loss of bone mass and changes in bone tissue. It can be caused by a variety of issues, but two common causes are lowered estrogen levels in people with ovaries and lowered testosterone levels in people with testicles. These lowered hormone levels can be caused by age, as well as other diseases.

Osteoporosis doesn‘t always cause obvious symptoms. But some of the more common symptoms are bone fractures and injuries related to minor falls, lifting, and even coughing.

Treatment for osteoporosis focuses on slowing or stopping bone loss. Proper nutrition, exercise, and medications are three of the most common treatments.


This rare disease is caused when the body makes too much growth hormone, which is mainly produced in the pituitary gland. Mostly diagnosed in middle-aged adults, it can cause organs, bones, cartilage, organs, and certain tissues to grow in size.

The common symptoms of acromegaly include:

  • swollen nose
  • swollen ears
  • swollen hands and feet
  • joint aches
  • a deeper voice than usual
  • an increase in sweating and body odor

Treatment for acromegaly includes medications, radiation therapy, and surgery.

The endocrine system is a complex collection of glands and organs that helps regulate various bodily functions. This is accomplished through the release of hormones, or chemical messengers, produced by the endocrine system.

(Video) The Endocrine System, Overview, Animation


What is endocrine system Short answer? ›

(EN-doh-krin SIS-tem) The glands and organs that make hormones and release them directly into the blood so they can travel to tissues and organs all over the body. The hormones released by the endocrine system control many important functions in the body, including growth and development, metabolism, and reproduction.

What are 3 main functions of the endocrine system? ›

Below are the 3 vital functions of your endocrine system.
  • Makes Hormones for Mood, Development, and Growth. Many different vital hormones are created and controlled within the endocrine system. ...
  • Sends Hormones into Your Bloodstream. ...
  • Regulates the Release of Hormones.

What is the endocrine system and its function? ›

Endocrine glands release hormones into the bloodstream. This lets the hormones travel to cells in other parts of the body. The endocrine hormones help control mood, growth and development, the way our organs work, metabolism , and reproduction. The endocrine system regulates how much of each hormone is released.

What is the endocrine system and why is it important? ›

The endocrine system controls growth and development during childhood, regulation of bodily functions in adulthood, and the reproductive process. The endocrine system is important for the control and regulation of all the major functions and processes of the body: Energy control. Reproduction.

What are the 5 major parts of the endocrine system? ›

The female ovaries, male testes, and pituitary, thyroid, and adrenal glands are major constituents of the endocrine system.

What is endocrine system 8th grade? ›

The Endocrine System is a system of ductless glands that secrete. hormones into the blood. These hormones regulate many vital body. functions, including growth (pituitary), reproduction (ovaries and testes), fight or flight responses (adrenal), and energy metabolism (thyroid).

What is the endocrine system quizlet? ›

the endocrine system is made up of glands that produce and secrete hormones that regulate the activity of cells or organs. These hormones regulate the body's growth, metabolism (the physical and chemical processes of the body), and sexual development and function.

Why is it called the endocrine system? ›

The endocrine glands do not have ducts to carry their product to a surface. They are called ductless glands. The word endocrine is derived from the Greek terms "endo," meaning within, and "krine," meaning to separate or secrete.

What is the endocrine system Quizizz? ›

What is the main function of the endocrine system? It creates chemicals, or hormones, that are sent around the body to maintain homeostasis. It creates electrical messages that are sent around the body to maintain homeostasis. It maintains the correct level of oxygen in the body to maintain homeostasis.


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