Types of Autonomic Nervous Systems

The autonomic nervous system is one of the two types of the peripheral nervous system. It is majorly responsible for regulating body processes that do not require conscious effort. The involuntary body functions involving the autonomic nervous system are breathing, blood flow, digestion, etc. It controls all the bodily processes that we cannot voluntarily manage. It is grouped into sympathetic and parasympathetic nervous systems. 

Let’s tell you about the types of the autonomic nervous system and their functions in detail.

What is the Autonomic Nervous System?

You must have heard about the autonomic nervous system as a part of the nervous system. As mentioned above, it regulates the automatic functions of the body. 

But, where does it fall in the nervous system, exactly?

The nervous system is categorized into two main categories; the central nervous system and the peripheral nervous system. The central nervous system comprises the brain and spinal cord, whereas the combination of all the nerves forms the peripheral nervous system. The peripheral nervous system uses cranial and spinal nerves to transmit signals. The peripheral nervous system is divided into the somatic and autonomic nervous systems.

The autonomic nervous system connects your brain to most vital organs performing involuntary functions. It acts like wiring between the brain and organs. 

The autonomic nervous system can be simply defined as the part of the nervous system involved in involuntary body functions.

Parts and Functions of Autonomic Nervous System

The autonomic nervous system makes use of ganglion and neurotransmitters to transmit messages throughout the body. The sensory information to the CNS through the autonomic nervous system regulates heartbeat, blood flow, breathing, etc. It stimulates the smooth muscles, cardiac muscles, and glands. ANS also stimulates the release of metabolic and cardiovascular hormones. Some of the common hormones involved in the autonomic nervous system include:

  • Epinephrine
  • Insulin
  • Glucagon
  • Vasopressin
  • Renin

While the functions of the autonomic nervous system are distributed between the sympathetic and parasympathetic nervous systems, its significant roles related to different organs include:


The autonomic nervous system regulates the body’s ability to produce sweat through sweat glands and the goosebump response-inducing muscles. Goosebumps refer to the condition when your body hair stands up in a surprising or fearful situation.


Your autonomic nervous system may generate hypersensitivity reactions from your immune system in response to an allergen or pathogen.


The smooth muscles in the bladder hold pee through autonomic response until you want to urinate.

Other autonomic functions include tear gland control, pupil focus, blood flow and heartbeat, breathing, reproductive functions, defecation, etc.

Types of Autonomic Nervous System

The autonomic nervous system is divided into two major types; the sympathetic and parasympathetic nervous systems. The enteric nervous system is a less well-known division of the autonomic nervous system.

Sympathetic Nervous System

The sympathetic nervous system is your body’s “fight or flight” response. It is also known as the thoracolumbar outflow as the preganglionic neurons arise from the 12 thoracic or initial 2 or 3 lumbar spinal segments. 

The autonomic nervous system typically regulates functions such as the cardiovascular system or homeostasis. However, the autonomic nervous system, when activated in stress conditions, produces large quantities of epinephrine. It also increases cardiac output and dilates the skeletal muscles and pupils. The sympathetic nervous system signals the body to release stored energy to increase muscle strength. It slows down processes like digestion to save energy utilized in the function. Precisely, it prepares the body for possible danger and directs the energy to vital organs.

Parasympathetic Nervous System

The parasympathetic nervous system works oppositely to the sympathetic nervous system and functions in “rest and digest” conditions. It regulates glands and reduces heartbeat or increases digestive secretions such as gastric juice. The Parasympathetic preganglionic neurons are in the sacral region of the spine or the brainstem. The pre and post-ganglionic neurons secrete acetylcholine along with cotransmitters.

Some primary functions of the parasympathetic nervous system include regulating saliva production through salivary glands, the production of tears in lacrimal glands, and the nasal mucosal glands secreting mucus in the air passage.

Enteric Nervous System

The enteric nervous system regulates the process of digestion throughout the GI tract. It contains extensive neural circuits that you can observe under a microscope made by renowned brands. They detect the current physiology of the gastrointestinal tract and provide appropriate output. The enteric nervous system is typically involved in fluid exchange in the GIT, local blood flow, and controlling gut movement.


What controls the autonomic nervous system?

The hypothalamus in your brain operates the autonomic nervous system despite not being a part of the system directly.

What causes autonomic dysfunction?

One common cause of autonomic dysfunction is poorly-controlled diabetes. It can lead to nerve damage and amyloidosis (protein buildup) in the organs.

How do you reset the autonomic nervous system?

Sighing is your body’s tension-releasing mechanism that helps reset the autonomic nervous system. Take a deep breath to balance your over-activated sympathetic condition to a balanced parasympathetic state.

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Lee Clarke
Lee Clarke
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