AUTONOMOUS NERVOUS SYSTEM: what is it, parts, functions and characteristics

The autonomic nervous system, a part of the nervous system, is so called because it works independently of our will; a process that does not develop under our conscious awareness is autonomous. The autonomic nervous system governs a wide range of processes in our body that are not necessary to consciously manage, such as breathing, heartbeat and processes digestives. In fact, the autonomic nervous system regulates 90% of the body's functions. With this article of Psychology-Online we will see then what is the autonomic nervous system, its parts, functions and characteristics.

Index

1. What is the autonomic nervous system
2. Parts of the autonomic nervous system
3. Functions of the autonomic nervous system
4. Characteristics of the autonomic nervous system

The nervous system is divided into:

• Central Nervous System (CNS): within which we find the brain and spinal cord.
• Peripheral nervous system (SNP): which is divided into autonomic nervous system (SNA) and somatic nervous system (SNS).

The autonomic nervous system is a part of the nervous system that is anatomically and functionally distinguished. Historically, this distinction dates back to the Bichat, which around 1800 distinguished between the animal way and the vegetative way, corresponding to the Fri from relation and the fri from nutrition. More specifically, the vegetative peripheral nervous system (autonomic, involuntary, visceral) represents the part of the peripheral nervous system which grafts the glands, the cardiac musculature and the smooth organs and blood vessels, thus affecting the functions of the body normally under unconscious control (for example, heart rate and blood circulation, respiration, digestion, etc.).

The autonomic nervous system can be divided into three parts:

1. The sympathetic nervous system

The sympathetic nervous system originates in the spinal cord, especially in the thoracic and lumbar areas. The processes of neurons present here target a series of structures, the ganglia, located near the spinal cord. That is why we speak of preganglial fibers (those that originate in the medulla) and postganglial fibers (those that start from the ganglion). The latter are directed toward a muscle or gland. Only a few preganglar fibers come into direct contact with nodes other than these.

2. The parasympathetic nervous system

The bodies of the neurons of the parasympathetic system are found in the sacral region of the spinal cord and in the elongated medulla of the brainstem, where cranial nerves III, VII, IX, and X form the parasympathetic preganglar fibers. These and those that come from the spinal cord target the nodes very close to the organ they must control. Hence the postganglionic fibers are directed directly to the target organ.

3. The enteric nervous system

The enteric nervous system (or metasympathetic) is formed, instead, by the set of nerve fibers that graft the viscera.

Below you can see a concept map of the classification of the nervous system.

Always active, the autonomic nervous system allows it to cope with the basic functions of the organism, working together with the somatic nervous system. In particular, the autonomic nervous system is the part of the peripheral nervous system that controls involuntary activities. The ANS controls the functions of internal organs (such as the heart, stomach, and intestines) and some muscles. It controls, in effect, the body's functions at rest and reflective reactions, and to do so it acts on smooth muscles (for example, in the skin around hair follicles, around blood vessels, in the eye and in the stomach, intestine and bladder) and in the heart.

In general, the sympathetic and parasympathetic systems exert the opposite effect on their targets; in this way they control functions such as:

• The dilation of the Pupils
• The production of saliva and mucus
• Heart rate
• Contraction of the muscles of the bronchi
• Stomach and bowel movements
• The accumulation of glycogen in the liver
• The production of urine
• Relaxing your bladder wall and opening your sphincter

In this article you can see the differences and functions between the sympathetic and parasympathetic nervous systems.

The autonomic nervous system, maintaining internal homeostasis, exercises integrated control and coordination of the numerous functions that allow the body to act as a whole. Therefore, it controls body temperature, which determines the rate of each chemical reaction, regulates blood circulation at an appropriate pressure, and cardiac effusion according to the metabolic demands of the body, maintains water balance and controls bowel movements and secretions glandular. It also regulates the secretion of various hormones that are important for the excretion of waste products, reproduction, behavior and other functions.

To perform all these functions, the autonomic nervous system must have local connections suitable with most cells and tissues and also with various parts of the nervous system central. The main control centers of the autonomous system are located in the hypothalamus and in the brain stem, where the centers for food intake and fluids, for sleep, for fluid regulation, for circulation, temperature and other functions. Other parts of the brain, such as the cerebral cortex, have nerve connections to the centers hypothalamic, so the impulses that come from them can reach the autonomic system and affect its functions.

From an anatomical point of view, the vegetative (autonomic) nervous system consists of both efferent (motor) and relative (sensory) nerve fibers; 75% of the fibers of the vagus nerve are relative. In the autonomic nervous system, the effective pathway is always constituted by two neurons (unlike that of the voluntary nervous system, which consists of a single motor neuron): a preganglionic neuron with the cell body located in the central nervous system and a postganglionic neuron, with the cell body outside of it, in a ganglion or in the wall of the organ innervated.

This article is merely informative, in Psychology-Online we do not have the power to make a diagnosis or recommend a treatment. We invite you to go to a psychologist to treat your particular case.

If you want to read more articles similar to Autonomic nervous system: what it is, parts, functions and characteristics, we recommend that you enter our category of Neuropsychology.

• Cangiano, A., Von Eluer, U. S. (1982). Encyclopedia of the Novecento. Autonomic nervous system. Rome: Treccani.
• Causarano, V. (2020). Autonomous or vegetative nervous system. Recovered from: https://www.vitocausarano.it/sistema-nervoso-autonomo-e-vegetativo/
• Chetta, G. (2019). Vegetative nervous system. Recovered from: http://www.giovannichetta.it/sistemanervoso.html#snvegetativo
• Humanitas (2020). Autonomic nervous system. Recovered from: https://www.humanitas.it/enciclopedia/anatomia/sistema-nervoso/sistema-nervoso-periferico/sistema-nervoso-autonomo