Table of contents:
- The autonomic nervous system: definition
- Functions of the Autonomic Nervous System
- Parts of the Autonomic Nervous System
- Difference between sympathetic and parasympathetic nervous system
- Function of the Sympathetic Nervous System
- Parasympathetic Nervous System: functions
- Diseases of the sympathetic and parasympathetic nervous system
- Summary of the anatomy and functions of the Autonomic Nervous System
- 1. Anatomy
- 2. Functions
- 3. Differences between SNS and SNP
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Both our body and the mind itself are regulated by the brain and all the connections that it contains. The nervous system is in charge of conducting signals between neurons and thus coordinating all the actions of the body. The human nervous system can be divided into two large parts: the central nervous system (or CNS), made up of the brain and the organs closest to it, and the peripheral nervous system (or PNS), made up of the nerves and neurons that they are outside the central nervous system.
In this Psychology-Online article, we will focus on a very specific part of the SNP: the autonomic nervous system (ANS). In addition, we will explain the main functions and differences between the sympathetic and parasympathetic nervous systems: two large ramifications of the ANS that are very important in our own survival as human beings.
You may also be interested in: Differences between central and peripheral nervous system Index- The autonomic nervous system: definition
- Difference between sympathetic and parasympathetic nervous system
- Diseases of the sympathetic and parasympathetic nervous system
- Summary of the anatomy and functions of the Autonomic Nervous System
The autonomic nervous system: definition
As we have commented previously, the ANS (also known as the vegetative nervous system) is located in the periphery of the nervous system, despite being activated by areas such as the hypothalamus, most of its activity is centered in the spinal cord, the nerves peripherals and brainstem. The nerves that leave the brain and go directly to all the organs of our body (efferent fibers) are part of the autonomic nervous system.
This anatomical organization is due to the fact that it receives and sends information from the viscera and many of the organs of our body to be able to regulate and correctly stimulate its vegetative functions.
Functions of the Autonomic Nervous System
This system has been shown to control the muscles that surround our organs, regulate the excretory system (sweat, urine, and other secretions), and participate in the following processes:
- Control of reflexes and involuntary actions
- Blood pressure
- Breathing
- Digestion
- Erection and ejaculation
- Involuntary muscle contraction and relaxation
- …
So that we understand it better, and as a summary, everything that our body does and that we do not usually pay attention to, is controlled by the autonomic nervous system.
Parts of the Autonomic Nervous System
This organization of nerves and neurons is divided into three main parts:
- Sympathetic Nervous System: responsible for regulating the body's activation responses
- Parasympathetic Nervous System: responsible for returning to a state of balance and conservation after the activation of the sympathetic system.
- Enteric Nervous System: also known as the "second brain" this system is the least known of the three, it is responsible for generating emotional responses from the secretion of neurotransmitters such as serotonin, dopamine and endogenous opioids. Thanks to this system, we better understand the relationship between neurotransmitters and emotions.
Next, we will develop in depth the concepts of the sympathetic and parasympathetic nervous system: their main differences and functions.
Difference between sympathetic and parasympathetic nervous system
Now that we know that we have a built-in system responsible only for controlling the involuntary functions of our body, it is normal to want to know more, what is each system in charge of? While it is true that each of those named above has a specific function, it is important to know the close relationship that exists between the sympathetic and parasympathetic nervous systems.
Both are different sides of the same coin, they are responsible for keeping our body in balance or homeostasis in the face of different external stimuli. However, the main difference lies in their functions: while one is responsible for activating our body, the other is responsible for relaxing it and returning to the natural state of the body.
Function of the Sympathetic Nervous System
The nerves, fibers and neurons of this system are responsible for putting our body in a physiological state of alert. When the brain sends an alert signal or cortical activation due to a stress situation, the SNS sends a message to the muscles and glands of our body so that they can start our body in the following way:
- The adrenal gland releases adrenaline throughout our bloodstream
- Dilate the pupils
- Speeds up the heart rate
- Opens the airways to increase oxygen in the blood
- Inhibits the digestive system to concentrate efforts on attack and flight tasks
- Maintains muscle tone
- Stimulates orgasm
Parasympathetic Nervous System: functions
In contrast to the SNS, we find the SNP. This system is responsible for returning all previously activated organs to our natural state. To do this, it sends signals to the brain so that it releases acetylcholine and reaches the neurons responsible for relaxing the muscles and organs. The parasympathetic nervous system has the following main functions:
- Constriction of the pupil
- Reduced volume of the lungs
- Decreased heart rate
- Stimulation of the digestive process
- Muscle relaxation
- Stimulation of sexual arousal (in this case, it is not the opposite response to the SNS, but rather complements it)
Diseases of the sympathetic and parasympathetic nervous system
As we have seen, this set of neurons and nerves is extremely important for our survival. Presenting a disease in either system can be a serious problem and we must detect it as soon as possible.
An imbalance in the SNS or SNP will be related to our ability to generate adequate bodily responses to our environment, the main examples of diseases of the sympathetic and parasympathetic nervous system are the following:
- Fibromyalgia: when the parasympathetic nervous system does not work properly, this disease characterized by enormous pain with no apparent physical explanation can appear.
- Multiple sclerosis: this neurodegenerative disease can appear due to the interaction of different factors, one of them is a failure in the autonomic nervous system.
- Parkinson's: although the appearance is not directly related to a failure in the ANS, the fact of presenting this disease can lead to a serious dysfunction in said system.
- Idiopathic orthostatic hypotension - also known as pure autonomic failure
- Diabetes: This endocrine imbalance is closely related to a malfunction of the parasympathetic nervous system. As we have seen previously, the parasympathetic nervous system is responsible for regulating some of the functions of the digestive system as well.
- Other diseases such as botulism, leprosy and Chagas disease can cause nervous system failures.
Summary of the anatomy and functions of the Autonomic Nervous System
By presenting so many names and technicalities, we have found it necessary to create a simple summary in order to correctly understand both the ANS and the sympathetic and parasympathetic nervous system:
1. Anatomy
The ANS is part of our peripheral nervous system, it is in charge of generating responses in our brain and controlling most of our organic functions. We therefore understand that the ANS is distributed throughout the body and is anatomically different from the Central Nervous System due to its position on our body map.
The nerves, the brain stem, the spinal cord, and some parts of the hypothalamus are the areas most involved in the autonomic nervous system. In turn, we divide the ANS into: sympathetic, parasympathetic and enteric nervous systems (SNS, SNP and SNE)
2. Functions
The main function of the ANS is to control our unconscious and vegetative functions. For example, we are not aware of the digestive process, however, there is a part of our system in charge of regulating it. The same goes for involuntary muscle tension, breathing, and many more adaptive responses.
3. Differences between SNS and SNP
The sympathetic and parasympathetic nervous systems are responsible for keeping our body in constant balance, while the SNS is responsible for activating alert functions when a stimulus produces stress, agitation or we perceive danger, the SNP is the one that directs our body to a state of tranquility and conservation.
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.
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