What are the parts of the endocrine system?

The endocrine system is made up of organs called glands. Glands

produce and release different hormones that target specific things in
the body. You have glands all over your body, including in your neck,
brain and reproductive organs. Some glands are tiny, about the size of
a grain of rice or a pea. The largest gland is the pancreas, which is
about 6 inches long.

The main glands that produce hormones include:

 Hypothalamus: This gland is located in your brain and controls

your endocrine system. It uses information from your nervous
system to determine when to tell other glands, including the
pituitary gland, to produce hormones. The hypothalamus
controls many processes in your body, including your mood,
hunger and thirst, sleep patterns and sexual function.
 Pituitary: This little gland is only about the size of a pea, but it
has a big job. It makes hormones that control several other
glands such as the thyroid gland, adrenal glands, ovaries and
testicles. The pituitary gland is in charge of many different
functions, including how your body grows. It’s located at the
base of your brain.
 Thyroid: Your thyroid is a butterfly-shaped gland in the front of
your neck. It’s responsible for your metabolism (how your body
uses energy).
 Parathyroid: These four tiny glands are no larger than a grain of
rice. They control the level of calcium in your body. For your
heart, kidneys, bones and nervous system to work, you need the
right amount of calcium.
 Adrenal: You have two adrenal glands, one on top of each
kidney. They control your metabolism, blood pressure, sexual
development and response to stress.
  Pineal: This gland manages your sleep cycle by releasing
melatonin, a hormone that causes you to feel sleepy.
 Pancreas: Your pancreas is part of your endocrine system, and it
plays a significant role in your digestive system too. It makes a
hormone called insulin that controls the level of sugar in your
blood.
 Ovaries: In women, the ovaries release sex hormones called
estrogen, progesterone and testosterone. Women have two
ovaries in their lower abdomen, one on either side.
 Testes: In men, the testes (testicles) make sperm and release
the hormone testosterone. This hormone affects sperm
production, muscle strength and sex drive.

CONDITIONS AND DISORDERS

What conditions and disorders affect the endocrine system?

Dozens of conditions can cause issues in the endocrine system. These

conditions can lead to health problems all over the body. Some of the
most common disorders are:

 Diabetes: This endocrine disorder affects the way your body

uses the energy from the food you eat. Diabetes develops when
the pancreas doesn’t make enough of a hormone called insulin,
or insulin doesn’t work as it should.
 Thyroid disorders: Several conditions can affect the function of
the thyroid gland. Hypothyroidism happens when the thyroid
doesn’t produce enough hormones. Hyperthyroidism occurs
when it creates too many hormones.
 Hypogonadism (low testosterone): In men, hypogonadism can
cause erectile dysfunction. It can also cause memory and
concentration problems, changes in muscle strength and low
 sex drive. It happens when the testes do not produce enough of
the sex hormone testosterone.
 Polycystic ovary syndrome (PCOS): A hormonal imbalance
causes women with PCOS to have irregular periods, abnormal
hair growth, excess acne and weight gain. It can lead to diabetes,
increased risk of metabolic syndrome and infertility.
 Osteoporosis: When a woman’s ovaries don’t produce enough
estrogen, bones become brittle and weak. Although it is more
common in women, men sometimes have osteoporosis when
testosterone levels get too low. People with an overactive
parathyroid gland (hyperparathyroidism) may also have weak
bones.

Chemicals called endocrine disrupters can also affect the endocrine

system. These chemicals appear everywhere — in pesticides, plastics,
cosmetics and even our food and water. Endocrine disrupters cause a
wide range of problems throughout the body by changing how
hormones send messages.
How common are these conditions?

 Diabetes: This condition is widespread. Almost 10% of people in

the United States have diabetes and 27% have prediabetes.
 Thyroid disorders: About 20 million Americans have thyroid
disease. Women are about five times more likely than men to
develop the condition.
 Hypogonadism: About 40% of men over 45 have low
testosterone. Levels of this sex hormone naturally drop as men
age. Other factors, such as a man’s diet, weight and other health
problems also affect testosterone levels.
 PCOS: This common condition affects about 5% to 10% of adult
women in the U.S. It is a leading cause of infertility.
  Osteoporosis: More than half of adults over age 50 have
osteoporosis. It is more likely to occur in women than in men.

CARE
How can I keep my endocrine system healthy?

Your endocrine system needs the same things the rest of your body
needs to stay healthy. You should exercise, eat right and see your
healthcare provider regularly.

If you have a family history of diabetes, thyroid disorders or PCOS, talk

to your provider. Managing these conditions can help you avoid a
hormone imbalance that can lead to health problems.

Endocrine system hormones

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 that recognize
and react to the hormone.

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

Secreting
Hormone Function
gland(s)

increases blood pressure, heart rate, and

adrenaline adrenal
metabolism in reaction to stress

aldosterone adrenal controls the body’s salt and water balance

cortisol adrenal plays a role in stress response

dehydroepiandrosterone adrenal aids in production of body odor and growth

 sulfate (DHEA) of body hair during puberty

works to regulate menstrual cycle, maintain

estrogen ovary pregnancy, and develop female sex
characteristics; aids in sperm production

follicle stimulating
pituitary controls the production of eggs and sperm
hormone (FSH)

glucagon pancreas helps to increase levels of blood glucose

insulin pancreas helps to reduce your blood glucose levels

controls estrogen and testosterone

luteinizing hormone (LH) pituitary
production as well as ovulation

melatonin pineal controls sleep and wake cycles

helps with lactation, childbirth, and mother-

oxytocin pituitary
child bonding

parathyroid hormone parathyroid controls calcium levels in bones and blood

helps to prepare the body for pregnancy

progesterone ovary
when an egg is fertilized

prolactin pituitary promotes breast-milk production

contributes to sex drive and body density in

ovary, teste,
testosterone males and females as well as development
adrenal
of male sex characteristics

help to control several body functions,

thyroid hormone thyroid including the rate of metabolism and energy
levels

Endocrine system diagram

Explore the interactive 3-D diagram below to learn more about the endocrine
system.
Conditions that can affect the
endocrine system
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

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 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
 diarrhea
 irritability
 a craving for salt or salty foods
 irregular periods

Treatment of Addison disease involves taking medications that help to replace

the hormones that your body isn’t producing enough of.
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

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.