The nervous system is a kind of apparatus that connects all organs, creates a relationship between their functions, which guarantees the smooth operation of the human body as a whole. The main element of this complex mechanism is a neuron - the smallest structure that exchanges impulses with other neurons.
Basic vegetative processes in the body
The organization of the autonomic nervous system (ANS) is available not only in humans and vertebrates. The term "vegetative" was introduced by scientists, based on the fact that this complex mechanism, consisting of chains of neurons, is also inherent in primitive organisms, regulating the elementary processes of their vital activity.
An English physiologist called the autonomic nervous system autonomous, since its functions are not amenable to conscious control or termination. In mammals, which, in fact, includes humans, it is responsible for several vital biological processes:
- work of the cardiovascular system;
- regulation of blood circulation;
- implementation of digestion, respiration;
- selection functions;
- reproduction and metabolism.
Departments of the autonomic system: physiological features
If we consider the autonomic system from an anatomical point of view, it can be conditionally divided into two subsystems: sympathetic (SNS) and parasympathetic (PNS). Their efferent pathways are based on a serial connection of neurons emanating from the central nervous system (CNS).
Anatomical differences between the sympathetic and parasympathetic nervous systems lie in the location of neuronal cell bodies - belonging to the SNS are located in the spinal cord of the thoracic and lumbar vertebrae, and those belonging to the PNS are grouped in the medulla oblongata and sacral parts of the spinal cord. The second neural circuit is located outside the CNS, it forms the ganglia in close proximity to the spine.
The role of the metasympathetic division
The sympathetic and parasympathetic divisions of the nervous system have a fundamental influence on the functioning of most internal organs through the so-called vagus nerve. If we compare the transmission rates of impulses of the central and vegetative systems, the latter is significantly inferior. The uniting SNS and PNS can be called the metasympathetic department - this area is located on the walls of the organs. Thus, all internal processes of the human body are controlled thanks towell-established work of vegetative structures.
The principle of operation of the vegetative departments
The functions of the sympathetic and parasympathetic nervous systems cannot be classified as interchangeable. Both departments supply the same tissues with neurons, creating an indestructible connection with the central nervous system, but they can have an absolutely opposite effect. The following table will help you visually verify this:
Organs and systems |
Sympathetic system |
Parasympathetic system |
| Pupils | expanding | tapering |
| Salivary glands | causes a small amount of thick liquid | intense production of watery secretions |
| Lacrimal glands | does not work | causes increased production of secretions |
| Contractility of the heart muscle, rhythm | induces an increase in heart rate, increases contractions | weakens, reduces heart rate |
| Vessels and circulation | responsible for the narrowing of arteries and increased blood pressure | virtually no effect |
| Respiratory Organs | helps to strengthen, expand the lumen of the bronchi | narrows the lumen of the bronchi, there is a decrease in breathing |
| Muscles | tones up | relaxes |
| Sweat glands | activates sweat production | does not work |
|
The work of the gastrointestinal tract and digestive organs |
slows down mobility | activates mobility |
| Sphincters | activates | slows down |
| Adrenals and endocrine system | production of adrenaline and norepinephrine | does not work |
| Genital organs | responsible for ejaculation | responsible for erection |
Sympathicotonia - disorders of the sympathetic system
The sympathetic and parasympathetic divisions of the nervous system are in an equal position, without the predominance of one over the other. In other cases, sympathicotonia and vagotonia develop, which is manifested by increased excitability. If we are talking about the predominance of the sympathetic department over the parasympathetic, then the signs of pathology will be:
- febrile condition;
- palpitations;
- numbness and tingling in tissues;
- irritability and apathy;
- increased appetite;
- thoughts of death;
- absent-mindedness;
- decreasesalivation;
- headaches.
Disorder of the parasympathetic system - vagotonia
If, against the background of weak activity of the sympathetic department, parasympathetic processes are activated, then the person will feel:
- excessive sweating;
- lower blood pressure;
- change in heart rate;
- short-term loss of consciousness;
- increased salivation;
- fatigue;
- indecision.
What is the difference between SNA and PNS?
The main difference between the sympathetic and parasympathetic nervous system lies in its ability to increase the body's capabilities in case of a sudden need. This department is a unique vegetative construct that, in an emergency, gathers together all available resources and helps a person cope with a task that is almost on the verge of his capabilities.
The functions of the sympathetic and parasympathetic nervous system are aimed at maintaining the natural functioning of internal organs, even in critical situations for the body. Increased activity of the SNS and PNS helps to overcome various stressful circumstances:
- excessive physical activity;
- psycho-emotional disorders;
- complex diseases and inflammatory processes;
- metabolic disorders;
- development of diabetes.
When a person experiences emotional upheavals, the autonomic nervous system begins to work more actively. The sympathetic and parasympathetic divisions enhance the actions of neurons and strengthen the connections between nerve fibers. If the main task of the PNS is to restore normal self-regulation and protective functions of the body, then the action of the SNS is aimed at improving the production of adrenaline by the adrenal glands. This hormonal substance helps a person cope with a suddenly increased load, it is easier to endure dramatic events. After the sympathetic and parasympathetic divisions of the autonomic nervous system have used up possible resources, the body will need rest. For a full recovery, a person will need 7-8 hours of sleep at night.
Unlike the sympathetic nervous system, the parasympathetic and metasympathetic vegetative divisions have a slightly different purpose associated with maintaining body functions in peace. The PNS works differently, lowering the heart rate and the strength of muscle contractions. Thanks to the parasympathetic component of the vegetative system, digestion is stimulated, including when the level of glucose is insufficient, protective reflexes (vomiting, sneezing, diarrhea, coughing) are triggered, aimed at freeing the body from harmful and foreign elements.
What to do if there are violations of the autonomic system?
Noticing the slightest violations of the functionalitysympathetic and parasympathetic divisions of the autonomic nervous system, you should consult a doctor. In advanced cases, violations lead to neurasthenia, gastrointestinal ulcers, hypertension. Drug treatment should only be prescribed by a qualified neurologist, but the patient is required to eliminate any factors that excite the sympathetic and parasympathetic nervous system, including physical exertion, psycho-emotional shocks, worries, fears and concerns.
To establish vegetative processes in the body, it is advisable to take care of a cozy homely atmosphere and receive only positive emotions. In addition to the above, physiotherapy, breathing exercises, yoga, and swimming should also be included. This contributes to the removal of the general tone and relaxation.
