Nervous system and principles of device operation

The medical art appeared as not the fruit of theoretical reasons but, on the

contrary, people started thinking about theoretical reasoning when methods

of treatment had been already found.
A. Celsus, III-II B.C.

A disease, in fact, is informational disorder at different levels of
organization of physiologic systems, whereas maintaining the life
and health is, in fact, the controlled balance. 
G.G.Gvidott, 1990

The nervous system ensures adaptation of the body to the external environment. Under the constantly changing conditions of existence the nervous system regulates the living activity of all tissues and organs, connects organs and parts of the body, ensures the feedback of the body relative to the requirements of the external environment (homeostatic and behavioral acts).

The nervous system unites the body into an integral system. All its multiple functions are performed by 40-45 billion of nerve cells – neurons. That is why, the name of apparatuses contain the component “neuro”, which means “operating with the nervous system as the nervous system proper”.

Neurons possess the following unique abilities:

• get excited (active state) under the effect of physical or chemical stimulus;
• accept, cipher, process information about the state of the external and internal environment of the body;
• transfer information in the form of electric pulses and by other ways to other nerve cells or organs (muscles, glands, vessels, etc.) by establishing the link between them;
• store the copy of information in their memory (the ability of nerve cells to store information allows the human brain – frontal lobe – to store in the human memory all which took place during the entire life, the volume of this memory is such that it contains all genetic memory of ancestors.

Nerve cells are of different forms and sizes (from 5 to 10 microns). Each neuron has short processes (dendrites) and long processes (axon) (Fig. 1). Dendrites receive information from other nerve cells. The number of short processes of each neuron may varies from 1 to 1,500. The axon serves for the transfer of the processed information: in one cases, from receptor structures of nerve cells of the skin, inner organs and tissues to the central nervous systems, in other cases – from the central nervous systems to organs, tissues and skin. That is why, long processes of nerve cells are called pathways. As a rule, one neuron is connected with a large number of other nerve cells which ensures their interaction and the possibility of formation of complex structures which regulate these or that functions.

Fig – 1

A complex of neurons which regulates this or that function form the nerve center (for example, vasomotor center, center of speech, respiratory center, etc.). In order to organize the nerve center neurons are grouped thus forming the nucleus center. In a number of cases, due to the fact that the length of processes may reach 1-1.5 m, neurons are united in a single functional group being located in different anatomic zones.

The major part of neurons, nerve centers and nuclei are located in the brain and spinal cord, that is why the latter are distinguished as the central nervous system.

The brain is located in the cavity of the skull and is surrounded by three membranes which protect it against a damage. The brain regulates the hormonal, immune, cardiac activity, blood pressure, breath, temperature, location of the body in space, motor activity, the need in food and liquid, reflex interaction of the body and environment, internal state of the body (homeostasis), mental activity, training and memory, emotions and speech, behavioral reactions, thinking, sleepless and sleep, consciousness as knowing own mental and physical activity.

The spinal cord is located in the cavity of the spine, it is surrounded by three sheaths and strengthened by ligaments. It starts from the upper edge of the cranial vertebra and goes up to 1-2 lumbar vertebra. With the help of complexes of processes of nerve cells the spinal cord is connected with the brain. The link between the spinal cord (and the brain, respectively) and the skin, support-motor apparatus and inner organs is also effected with the help of processes of nerve cells which at the outlet from the spinal cord and brain get interlaced forming radices, nerve plexuses, nerve trunks, spinal nerves (Figs 2-4). The set of these nerve formations and their multiple branches forms the peripheral nervous system.

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Fig – 2	Fig – 3

 Fig – 4

Depending on their functions, all nerve cells may be divided into three groups:

1. which bring information signals from receptors of sensation organs (sensor systems of the body) to the brain and spinal cord. They are called sensitive or afferent;
2. which transfer information from the brain and spinal cord to all organs and tissues (executors). They are called motor or efferent;
3. which serve to interconnect neurons of the brain and spinal cord. They are called intercalary neurons (interneurons). These cells form the most numerous group of nerve cells and differ sig nificantly as to the form and function.

Receptors are endings of processes of sensitive nerve cells in the body which are evolutionary adapted for acceptance of certain stimulus from the external or internal environment and for transformation of its physical or chemical energy into the form of nerve excitation. All receptors which accept stimuli (signals) from the external environment relate to exteroreceptors; these accepting stimuli from muscles, tendons, joints and ligaments, to propri-oreceptors; from inner organs, to interoreceptors.

In the sensor system, signals are coded (ciphered) by the binary code, i.e. by availability or absence of the electric pulse in this or that period of time. Such method of coding is extremely simple and stable to interference. Information about the stimulus and its parameters is transferred in the form of single pulses as well in the form of groups, batches of pulses. The amplitude, duration and shape of each pulse are similar but the number of pulses in a batch, their repetition rate, duration of batches and intervals between them, also the time pattern of the batch differs and depends on characteristics of the stimulus. The sensor information is also coded by the number of simultaneously excited neurons and by their location in the neuron layer. As distinct from telephone and television codes which are decoded by restoration of the initial form of a message, in the sensor system such type of decoding does not take place.

The entire nervous system is conventionally divided into two main sections – somatic sensor (animal) and vegetative (visceral).

The somatic sensor nervous system provides the skin and sensation organs with sensitive nerves, it is responsible for functioning of the support-motor apparatus (bones, joints, muscles).

The vegetative nervous systems is responsible for regulation of functioning of the cardiovascular system, respiratory organs, digestive apparatus, endocrine glands, urogenital organs, it also controls feeding of muscles (Fig. 5). Same as the somatic sensor, the vegetative nervous system has its representation in the brain and spinal cord (central section) and peripheral, or out-of-brain, section (ganglions, nerve trunks and nerves going to inner organs). The vegetative nervous system is divided into two parts: sympathetic nervous system and parasympathetic nervous system.

Fig – 5

Sympathetic-parasympathetic duality by which either stimulation or brake of working organs is induced contributes to preservation of the dynamic balance of corresponding functions (Table 4).

Parasympathetic stimulation causes the inhibition action in some organs and the stimulation effect in others. Also, sometimes, the sympathetic system is of the stimulating character, sometimes, of inhibition. Though often sympathetic activation causes the change of functioning of the corresponding organ opposite to the effect of parasympathetic activation it is not correct to look at interconnection of two sections of the vegetative nervous system and antagonistic. On the contrary, together they ensure the complete adaptation of the body to the changing conditions of environment, i.e. act in the final end as synergists (collaborators).

Table 4
Responses of Organs at Stimulation of Sympathetic and Parasympathetic nerves (Tabeev D.M., 2001, pp 92-93)

Organs	Parasympathetic system	Sympathetic system
Heart frequency heartbeat force conductivity Vessels skin muscles peritoneo-pelvic organs inner organs coronary lung brain salivary glands external genital organs	inhibition – –   – – dilatation constriction – dilatation – –	stimulation – –   constriction dilatation constriction dilatation – constriction – –
Flat muscles   esophagus cardiastomach pylorus bowels rectum sphincter muscle of anus urinary bladder (detrusor) cystic sphincter ureter bronchus iris ciliary muscles pilomotor muscles third eyelid penis uterus gravid uterus non-qravid uterus	contraction dilatation relaxation tonus and peristaltic increase relaxation tonus and peristaltic contraction increase contraction increase contraction constriction constriction contraction – – erection varies depending on type of living and functional state – –	increase contraction tonus and peristaltic decrease contraction tonus and peristaltic decrease relaxation contraction relaxation – dilatation – – relaxation – – ejaculation varies depending on type of living and functional state contraction relaxation
Glands  salivary nasal gastric pancreatic sudoriferous islets of Langerhans brain layer of epinephros lever main metabolism	stimulation – – – – stimulation – – –	stimulation inhibition – – stimulation – – glycogenolysis improvement

The vegetative nervous system coordinates and adapts by the nerve and humoral way the activity of all organs, takes part in preservation of the dynamic balance of living functions.

It seems that ancient eastern ideas about the balance of the body achieved as the results of the harmony of two opposite phenomena apparently can be considered as the dynamic stability of homeostasis of the body which is ensured due to the functioning of the vegetative nervous system (D.M. Tabaeva, 2001).

Functioning of somatic sensor, sympathetic and parasympa-thetic parts of the vegetative nervous system is effected with the help of the complex reflex activity aimed at self-regulating by the body of the stability of the internal environment.

Reflex, the response of the body to any stimulus, represents a functional units of the activity of the nervous system. The diagram of simplest reflex: “stimulus – response”. However, as far as the human being is concerned, the reflex activity is the result of complex processing of information. For the optimal response to the stimulus the control for the result of this response is necessary. This control is effected by a system which transfers from the executing organ (effector) to command centers information about the fulfillment of the command by the effector and whether the useful for the internal environment of the body results is obtained. At this, receptors accept not only the primary (reason) stimulus but also the response to this stimulus. Availability of such control turns the reflex arch into the reflex ring via which nerve pulses are permanently circulating (direct link and feedback). This allows registration of any abnormality and making corrections. According to experimental data, during only 1 second nerve cells per-form 100 trillion elementary operations (the latest computer version is capable of making only one billion).

Due to the constant instantaneous receiving of information from the outside and from all organs and tissues of the body as well as due to quick processing of this information the nervous system every second regulates the functioning state of all organs and sys-tems by increasing or decreasing their functional activity to the optimum level in order to maintain stability of the internal systems of the body.

For example, in the case of an increase in the body temperature due to external (hot weather) or internal (infection) reasons, a normally functioning body will not overheat. The temperature of the body is regulated by neural feedback mechanisms which operate primarily through the hypothalmus (which contains not only the control mechanisms, but also the key temperature sensors.)

The mechanism of this self-regulating phenomenon is summarized as follows:

1. interoreceptors register an increase in the internal temperature beyond the safe level for the human body;
2. electric pulses sent via afferent paths transmit this information to the central nervous system (Fig. 7);
3. there it is analyzed, a decision reached and the command for implementing this decision is transferred to the executive section of the brain (see Fig. 6);
4. via efferent conducting paths, electric pulses from the brain send the solution to the organ executors;
5. after receiving the command, skin blood vessels are dilated, and at almost exactly 37 degrees sudoriferous glands begin functioning (Fig. 8);
6. as a result, the skin operates as a radiator by losing heat from the expanded vessels to the environment;
7. sudoriferous glands produce abundant sweat, and evaporation, as known by the lays of physics, increases the heat transfer;
8. by these means, the high temperature is decreased and normalization of the body’s internal environment is restored;
9. feedback (back afferentation) to the central nervous system of the adjusted condition has been occurring throughout the remedial process, until finally the measured temperature is comparable with the standard, and the intense functioning of efferents (blood vessels and sudoriferous glands) ceases (Fig. 9).

Fig – 6

Fig – 7

Fig – 8

Fig – 9

At the effect of excess or permanent similar stress stimuli as well as at any pathological state or disease resynchronization, disagreement of functioning of the nervous system takes place. Regulatory systems of the complex reflex activity do not ensure the optimal functioning of organs and systems of organs. A persons starts feeling bad all the time, frequent acute diseases develop, chronization of diseases and derangement of metabolism take place.

Under these conditions the use of the unique signal (batches of pulses) of apparatus of DENS-therapy DENAS which operation is based on the principle of the “biological” feedback leads to the recovery of regulatory abilities of the nervous system and recovery of a man.

For example, at disturbance of nerve regulation of children an increase in the body temperature due to distortion of information flows does not result in dilatation of peripheral blood vessels and activation of functioning of sudoriferous glands. The necessary heat transfer does not occur. As the result, the skin of such patients is pale and cold, their feeling gets worse significantly up to vomiting, delirium, algospasm and loss of consciousness. If under these conditions you apply electrodes of apparatus DENAS to a certain skin zone, the neuron-like signal via conduction tracts of the nervous system will reach the central nervous system and form their the necessary in this situation response. After that, the command (signal) required for normalization of the body internal environment will go to organ executors which will result in normalization of the body temperature and improvement of the patient state (Fig. 10).

Fig – 10

In a similar way, application of devices of DENS-therapy on other certain biologic energy informational zones and influence on the receptor system of the skin lead to elimination of other functional disorders of the body.