The Endocrine System
What Is the Endocrine System?
The endocrine system is a messenger system consisting of feedback loops of hormones released by the organism’s internal glands that directly into the circulatory system, regulating the distant target organs. The hypothalamus is the neural control center for all endocrine systems in vertebrates.
It is similar to the nervous system in that it plays an essential role in controlling and regulating many functions of the body. It is a network of organs and glands located throughout the body. The endocrine system is responsible for almost every cell, organ, and function in your body. It uses chemical messengers called hormones.
What Is a Gland?
A gland is an organ that forms and puts in your body certain hormones that work. The endocrine glands and exocrine glands release your substance into your bloodstream.
Endocrine System Functions
- It makes hormones that regulate your organs, metabolism, mood, Reproduction, growth, and development.
- It also controls how your hormones are released.
- It sends this hormone into your bloodstream so that it can travel to other parts of the body.
- It regulates sexual function, heart rate, blood pressure, appetite, sleeping and waking cycles, body temperature.
Glands that make up the Endocrine System
The endocrine system is consisting of many glands. In the brain are the pituitary gland, pineal gland, and hypothalamus. In the neck are the thyroid and parathyroid glands. Between your lungs is the thymus, the adrenals are above your kidneys, and the pancreas is behind your stomach. Your ovaries (if you are female) or testicles (if you are male) are in your pelvic region.
Glands and their hormones functions
Hypothalamus 
Hypothalamus connects your endocrine system to your nervous system. Its primary function is to tell the pituitary gland to start or stop making hormones.
Pituitary gland
It is the master gland of your endocrine system—the Pituitary gland using information from your brain to tell other glands in your body what to do.
The pituitary gland makes many essential hormones, including
- Growth hormones
- Prolactin: that helps to breastfeed mothers make milk.
- Corticotropin / ACTH (adrenocorticotrophic hormone): that stimulates the adrenal glands to produce certain hormones.
- Antidiuretic hormone (ADH): controls blood pressure and helps regulate the body’s water balance through its effect on the kidneys.
- Thyroid-stimulating hormone (TSH): that stimulates the production and secretion of thyroid hormones.
- Oxytocin: that helps the milk to be released during lactation.
- Luteinizing hormone: that regulates estrogen in women and testosterone in men.
Pineal gland
The pineal gland makes a chemical called melatonin that helps your body get ready for sleep.
Thyroid gland 
The thyroid gland makes thyroid hormone that controls your growth and metabolism. If this gland does not work well enough (a condition called hypothyroidism), everything is slower. Your heartbeat may be faster. You may have constipation. And you can gain weight. If it gets too much (hyperthyroidism), everything gets faster. Your heart can run. You may have diarrhea. And you can lose weight without trying. This gland also produces the hormone calcitonin, which can contribute to bone strength by helping to incorporate calcium into the bone.
Parathyroid
It is a combination of four small glands behind your thyroid. They play a role in bone health. The glands produce parathyroid hormones that control your phosphorus and calcium levels.
Thymus
Thymus glands make white blood cells called T lymphocytes that fight infection and are essential when a child’s immune system develops. The thymus begins to shrink after puberty.
Adrenals
Adrenals are best known for producing the “fight or flight” hormone adrenaline (also called epinephrine), both of which also make glandular hormones called corticosteroids.
They produce hormones.
- Adrenaline: that increases heart rate, metabolism, affects oxygen levels, sexual function, and blood pressure in reaction to stress.
- Aldosterone: that controls the body’s salt and water balance.
- Cortisol: that plays a role in stress response.
- Dehydroepiandrosterone sulfate (DHEA) helps produce body odor and growth of body hair during puberty.
Pancreas 
These organs are part of both your endocrine and digestive systems. Pancreas also makes digestive enzymes that break down food. This organ also makes the hormones insulin and glucagon. It ensures your blood flow and the right amount of sugar in your cells.
For people with type 1 diabetes, if your body doesn’t make insulin, your blood sugar levels can rise dangerously. The pancreas usually makes some insulin but not enough in type 2 diabetes.
Ovaries
In women, ovaries make estrogen and progesterone. These hormones help breast development during puberty, support pregnancy, regulate menstruation, and when the egg is fertilized, it helps the body prepare for pregnancy.
Testes
Testes make testosterone hormones in men. During puberty, it helps them grow body and facial hair . Testes also tell the penis to grow and play a function in making sperm.
Conditions that can affect the endocrine system
The levels of hormones can be too high or too low sometimes. If this occurs, it can have several impacts on your health. Signs and symptoms depend on hormones that are out of balance.
Here’s a look at some of the conditions that can alter the endocrine system and change your hormone levels.
Hyperthyroidism
Hyperthyroidism occurs when your thyroid gland produces too much thyroid hormone. It can be due to many factors, including autoimmune conditions.
Common symptoms of hyperthyroidism include:
- Fatigue
- Diarrhea
- Weight loss
- Nervousness
- Fast heart rate
- Trouble sleeping
- Issues tolerating heat
Treatment depends on the severity of the condition, as well as the underlying cause. Possibilities include radioiodine therapy, surgery, or medication.
Graves’ disease is a common form of hyperthyroidism and is an autoimmune disorder. The immune system attacks the thyroid in people with Graves’ disease, causing it to produce more thyroid hormones than normal.
Hypothyroidism
When your thyroid does not produce enough hormones for the thyroid, hypothyroidism occurs. Like hyperthyroidism, there are many possible causes.
Common symptoms of hypothyroidism include:
- Fatigue
- Weight gain
- Constipation
- Fertility issues
- Slow heart rate
- Dry skin and hair
- Irregular periods
- Issues tolerating the cold
Treatment for hypothyroidism involves increasing your thyroid hormone through medication.
Cushing syndrome
High levels of the hormone cortisol cause Cushing’s syndrome.
Some common symptoms of Cushing syndrome include:
- Weight gain
- Irregular periods
- Thin skin that bruises easily
- Sexual drive and fertility decreased in men
- Slow recovery from cuts, abrasions, and insect bites
- Accumulation of fat in the face, middle section, or shoulders
- Persistent scars, especially on the arms, thighs, and abdomen
Treatment depends on the problem of the condition and may include radiation therapy, surgery, or medication.
Addison disease
Addison disease happens while your adrenal glands do not produce enough cortisol or aldosterone.
Symptoms include:
- Fatigue
- Diarrhea
- Irritability
- Weight loss
- Abdominal pain
- Low blood sugar
- Irregular periods
- Nausea or vomiting
- A craving for salt or salty foods
Treatment involves taking medications that help replace hormones that your body does not produce enough.
Diabetes
Diabetes is a condition in which your blood sugar levels are not properly regulated.
Symptoms include:
- Fatigue
- Irritability
- Weight loss
- Frequent infections
- Frequent urge to urinate
- Increased hunger or thirst
Diabetes treatment may include insulin therapy, medication, and blood sugar monitoring. Lifestyle changes, such as exercising regularly and eating a balanced diet, can also help.