The autonomic nervous system

The autonomic nervous system (ANS) regulates certain bodily processes, such as blood pressure and respiratory rate. This system works autonomously, without the conscious effort of a person. It has two main divisions: the sympathetic nervous system and the parasympathetic nervous system.

The ANS controls involuntary actions. This is because it receives information from internal organs, including blood vessels, stomach, intestines, liver, kidneys, bladder, genitals, lungs, pupils, heart and digestive glands, and acts on its function.

After the autonomic nervous system receives information about the body and the external environment, responds by stimulating bodily processes. Usually through the sympathetic division, or by inhibiting them through the parasympathetic division.

Functions of the autonomic nervous system

Functions of the autonomic nervous system

The functions of the autonomic nervous system are as follows:

  • Urination.
  • Digestion.
  • Defecation.
  • sexual response.
  • Blood pressure.
  • Body temperature.
  • Heart and respiratory rate.
  • Metabolism (which affects body weight).
  • The balance of water and electrolytes (such as sodium and calcium).
  • The production of bodily fluids (saliva, sweat and tears).

Many organs are controlled primarily by the sympathetic or parasympathetic division. Sometimes the two divisions have opposite effects on the same organ. For example, the sympathetic division increases blood pressure and the parasympathetic division decreases it.

Generally, the two divisions work together to ensure that the body responds appropriately to different situations.

The division Cute prepares the body for stressful or emergency situations (fight or flight). Thus, sympathetic division increases the heart rate and the strength of the heart’s contractions, and widens (dilates) the airways to facilitate breathing.

It causes the body to release stored energy. Muscle strength increases. This split also makes your palms sweat, pupils dilate, and your hair stand on end. It slows down bodily processes that are less important in emergencies, such as digestion and urination.

For his part, the division parasympathetic controls the process of the body during ordinary situations. In general, the parasympathetic division preserves and restores.

It slows down the heart rate and lowers blood pressure. Stimulates the digestive tract to process food and eliminate waste. The energy from processed foods is used to restore and build tissue.

Both the sympathetic and parasympathetic divisions are involved sexual activity, as well as the parts of the nervous system that control voluntary actions and transmit sensations from the skin (somatic nervous system)

autonomic disorders

against diabetes

Autonomic disorders can be the result of damage to the autonomic nerves or those parts of the brain that help control bodily processes. It should be noted that such damage can occur on its own, without a clear cause.

Common causes of autonomic disorders are diabetes (the most common cause), peripheral nerve disorders, aging and Parkinson’s disease. Other less common causes include autonomic neuropathies, multiple system atrophy, spinal cord disorders, and some medications.


In men, erectile dysfunction can be an early symptom of an autonomic disorder.

Autonomic disturbances often cause dizziness or lightheadedness due to an excessive drop in blood pressure when a person stands up (orthostatic hypotension).

On the other hand, people may sweat less or not at all and thus become heat intolerant. The eyes and mouth may be dry.

After eating, a person with autonomic disorders may feel prematurely full or even vomit because the stomach empties too slowly (gastroparesis). For their part, some people suffer from urinary incontinence, usually because the bladder is overactive.

Other people have urinary retention because the bladder is not active. Constipation may occur or bowel control may be lost. The pupils cannot dilate and contract with changes in light.


blood pressure

Doctors can check for signs of autonomic disorders during the physical exam. You can do a tilt table test to see how your blood pressure and heart rate change when you change positions.

Blood pressure is also measured continuously while the person does a Valsalva maneuver (trying to exhale forcefully without letting air escape through the nose or mouth, similar to straining during a bowel movement).

The sweat test is also performed. For this, the sweat glands are stimulated by electrodes filled with acetylcholine and placed on the legs and forearms. Sweat volume is then measured to determine if sweat production is normal.

In the thermoregulatory sweat test, a dye is applied to the skin and the person is placed in a closed, heated compartment to stimulate sweating. Sweat causes the dye to change color.

Doctors can evaluate the pattern of sweat loss, which can help them determine the cause of the autonomic nervous system disorder

Treating the cause (if identified)

Conditions that may contribute to the autonomic disorder are evaluated. If such conditions are not identified or cannot be treated, the focus is on relieving symptoms.

By applying some simple measures and certain drugs (if necessary) it is possible to alleviate some symptoms of autonomic disorders. These measures are as follows:

  • Sweating reduced or absent. For this symptom it is useful to avoid hot environments.
  • Orthostatic hypotension. People are advised to raise the head of the bed about 4 inches (10 centimeters) and get up slowly.
    • It may help to wear a supportive or compression garment, such as an abdominal bandage or compression stockings.
    • Consuming more salt and water helps maintain blood volume in the bloodstream and therefore blood pressure.
  • Urinary retention. If urinary retention occurs because the bladder can’t contract normally, people can be taught to insert a catheter (a thin rubber tube) through the urethra and into the bladder.
    • The catheter allows urine retained in the bladder to drain, providing relief.
  • Constipation. A diet high in fiber and stool softeners is recommended. If constipation persists, enemas may be needed.
  • Erectile dysfunction. Treatment usually consists of drugs such as sildenafil, tadalafil or vardenafil taken by mouth.
    • Sometimes constriction devices (bands and rings placed at the base of the penis) or suction devices are used.

Whatever the underlying cause, it is essential to always follow your doctor’s instructions. In this way, not only can improvement be achieved, but complications can also be prevented.

The post The Autonomic Nervous System first appeared in research-school.



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