General nosologyGeneral nosology (from the greek word "nosos" - disease) deals with the concept of disease and pathologic pro-cesses, the theory of the causes and conditions of their origin (etiology) and the mechanisms of their onset and development (pathogenesis). It also studies the organism's reactivity and its significance in pathology.Concept of diseaseOne of the most important problems of pathologic physiology is to elaborate a scientific definition of disease. A correct view of disease helps to establish the general regularities of its onset and development, which is in its turn necessary for prevention and treatment of diseases. It is difficult, however, to find a definition of disease that would take in all of its main features.The concept of disease was modified at each stage of the development of pathology, in keeping with the level of knowledge.The following definitions are confirmed in modern medicine.Definition of health.According to definition supposed by experts of World Health Service Organization the health is the state of full physical, psychical and social well-being of person.Disease is, a qualitatively new vital activity that is caused by special agent action and essentially has the fol -lowing characteristics:(i) functional and structural disturbances in different organs and organ-systems;(ii) combination of mechanism of not only injury but also of defense, compensation and recovery;(iii) impairment of adaptation of environment and reduced capacity for work and socially useful activity.It should be stressed that two closely associated phenomena must be distinguished in the picture of any disease - the injury and the organism's counteraction to the injury, or the "physiologic measures" against it, i.e. defen -sive physiologic adjustments. In higher animals and man these adjustments are ensured by the activity of the central nervous system and lead to restoration of functions.Often manifested as a complex of intensified or weakened physiologic processes the disease assumes a number of new qualitative aspects. It is qualitatively a new process. For example, the febrile process is conditioned by a quantitative disturbance in the ratio between heat loss and heat production, but the resultant fever is a specific process with specific features of metabolism and heat regulation. The peculiarities of heat regulation in a fever-ish patient are manifested, for example, in a lowered capacity for adjustment to variations in external tempera-ture.The concept of disease includes the concepts of a pathologic reaction, pathologic process and pathologic state.A pathologic reaction is the relatively short-term reaction of a separate functional sys-tem of organism in re-spose to unusial stimulation. This reaction oversteps the limits of physiological norm and may be manifestation of not only disorder but also of defensive and adaptive mechansms.A pathologic process is the relatively long organism response to pathogenic action and is based on a disturbed function, and not infrequently, structure. It manifests in changes of all organism and includes pathologic and defensive reactions. Disease is a more complex phenomenoii including different pathologic processes and reac-tions as its constituents.Thus, the pathologic process does not present a definite picture of disease and is only a constituent of a complex of phenomena characterizing a disease. For example, elevated arterial pressure in hypertensive vascular disease is one of the pathologic processes characteristic of this disease; the concept of hypertensive vascular disease in-cludes, in addition to elevated arterial pressure, other changes in different organs and systems of the organism.A pathologic state is the steady irreversible change of structure and function of an organ and tissue. As a rule it is a consequence of the previous pathologic process or disease. A pathologic state develops very slowly or does not develop at all.For example, a transition of the pathologic process to a pathologic state is observed in the change of the active progressive form of pulmonary tuberculosis to the fibroid form.A disturbance in the adaptation of the organism to its environment (for example, in cases of excessive func-tional load or infection) may lead to a change of a pathologic state to a pathologic process again.Manifestations of disease.Disease, pathologic process and pathologic state are characterized by certain manifestations. The following types of these manifestations are distinguished in accordance with their characteristics:1. with their origin: subjective and objective;2. with their character and diagnostic significance: speficic, pathognomonic, non-specific;3. with their significance in disease development: cardinal (guiding), assident, and impending;4. to the spreading of change: focal and general.

1) Objective manifestation of disease are registered by investigator or with registering instruments; subjective ones are the patient's sensations and complaints.2) Specific manifestations of disease are caused by specific action of nosopoietic agent. They define the charac-ter of disease and allow to diagnosticate it.Specific sign that is met with alone concrete disease is called pathognomonic sign. For example, multiple tophi are the pathognomonic sign of gout. The tophus is a tissue node, contaiting crystals of sodium urate.Non-specific manifestations are found in different diseases. They usually deal with nervous and hormonal regu-larities of defensive and compensatory reactions ensuring limiting and elimination of lesions.Combination of signs and symtoms characterizing the given concrete disease is called symptom complex. For example, tachicardia, heightened basal metabolism, irritability, exophthalmia each taken separately may be met with different diseases but their association characterizes thyrotoxicosis.Combination of the interdependent in their development changes in two or more organs or systems of organism is called syndrom. For example, cardiopulmonary syndrome may be met with the diseases in the heart and lungs. An another example is a hepatolienal syndrome. Some disease were described by investigators as syn-dromes and keep their names.Periods and duration of disease.The following principal periods in the course of disease may be distinguished:1) latent, 2) prodromal, 3) period of marked manifestations and 4) outcome.Such development of disease is called typical and usually appears in infectious disease.The latent period lasts from the begining of the action or entrance of the infective agent to the manifestations of the organism's reaction in the form of detectable morbid phenomena or symptoms. In infectious disease this pe -riod is known as the incubation period. The latent period varies in its duration from several minutes to several months and even years. It is apparently determined by the organism's reaction to the action of the causative agent, its ability to overcome the resultant disturbances by means of its defence mechanisms. (Intoxication oc-curs almost instantly or within several minutes only after the action of powerful poisons). Ascertainment of the latent period is of great practical importance for the prevention and treatment of the disease.The prodromal period (from the Greek word "prodromes" - running before) lasts from discovery of the first sings of the disease to its complete manifestation. For example, the onset of infectious disease is often charac-terized by indefinite manifestations, such as general indisposition, sometimes chills, headache, inappetence, rise in temperature, etc.The period of marked manifestations usually follows the prodromal period. It is the period of development of all the principal morbid phenomena. Some diseases, especially infectious diseases, run a rather definite course. (For example, typhus usually lasts 13-16 days, measles - 8-10 days). Other diseases, particularly chronic dis -ease, do not have a definite duration.Outcome of disease.In some cases the disease ends in restoration of functions and complete recovery. However, complete restora-tion may only be imaginary. Thus, after infection the properties of the host alter just the same; the host acquires a state of immunity to the given infection (for example, smallpox, scarlet fever, typhoid fever) or, on the con-trary, becomes more susceptible to it (for instance, erysipelas).If the functional disturbances caused by the disease have not completely disappeared the cure is incomplete. Sometimes structural and functional changes persist; for example, the heart valves retain lesions after inflam-mation, or a joint remains immobile as a result of a tuberculous process in it.If the organism cannot adjust itself to the altered conditions of existence, its adaptation mechanisms become ex-hausted, further vital activity becomes impossible, and the third possible outcome of the disease - death - en-sues.Atypical disease development.Atypical disease development is a deviation from above destribed periodicity. The following basic forms of atypical disease development are known: relapse, remission, exacerbation, complication, abortive form and slight form.Relapse (or recidivation) is a recurrence of the morbid phenomena after seeming recovery. Cause of relapse is the same as one of the primary basic disease. Relapse may be often observed1) in infectious diseases not providing the steady immune resistance;2) as a consequence of action of provoking factors decreasing organisms resistance (for example, professional and other intoxications, overcooling, psychic strain, bad conditions of life and etc.);3) as a result of incomplete cure.To prevent relapse of disease it is necessary:

1) rational treatment of the primary acute disease,2) elimination of actions decreasing organism resistance and using of ones increasing it.Remission is weakening of morbid phenomena in result of successful clinical cure or hightening of non-specific resistance of organism. In infectious and psychic disease remission may be natural phase of the disease and a constituent of its cyclic development. The following types of remission are known: (i) complete or incomplete; (ii) long (stable) or short-term.In chronic disease stable and complete remission may last for several years but it should not regarded as recov-ery. So the physician have to undertake measures for prevention of relapse.Excerbation (or acute condition) is enhancing of disease manifestation. As a rule it is peculiar to chronic dis-eases but may also occur in acute ones. It arises as a result of cure stopping and decreasing in general organ-ism's resistance.Complication is a quite new disease arising in the organism weakened in result of the primary basic disease. It may arise during of the periods of marked manifestation and the recovery.For example, influenza virus decreases in resistance of the pulmonary tissue and in result of it pneumococcus may cause pneumonia as the complication of influenza.To prevent complication it is necessary to provide:1) rational cure of basic disease;2) maintanence of defensive possibilities or organism;3) favorable conditions of functioning of open to injury organs.Slight (effaced) forms. Weak expression of detectable morbid phenomena even in the period of marked signs characterizes the slight (effaced) form of disease. In this case it is difficult to diagnosticate disease correctly and begin the treatment in time.Abortive form. Short duration of pathologic manifestations in the most of diseases. In this case it is necessary to take into consideration that structural changes in tissues and organs may persist for a long period after disap-pearance of disease manifestations. Therefore, appropriate treatment and regimen must be continued in due manner.The main principles of disease classification. Diseases are divided according to:1) etiology into infectious, uninfectious, traumatic, professional and etc.;2) primary pathogenesis mechanism into diseases with primary physiological mechanism of pathogenesis and diseases with primary genetic lesions;3) level of injury to functioning structures into: molecular, chromosome, cellular, tissue, organ and systemic diseases;4) changes of immune reactivity into allergic, non-allergic, immune defficiences;5) prevalent injury of organs and systems or organism into: diseases of the heart and vessels; the respiratory diseases, diseases of degestive system and so on;6) clinical cure method into: surgery diseases, therapeutic diseases and so on;7) patient's age into: infantile diseases, children's diseases, diseases of adults and etc.;8) sex into femal and male diseases;9) disease duration into acute, subacute and chronic; 10) international statistic classification.Acute diseases last a short time - from several days to 2-3 weeks, subacute - from 3 to 6 weeks; chronic dis -eases are last more infrequently results of acute disease and last more than 6 weeks. However, these periods cannot be definitely fixed. The duration of a disease depends on the characterstics of the infective agent and the intensity and duration of its action on the given organism, as well as onthe properties of the infected organism.The international Statistic Classifiction of diseases was affirmed by World Health Service Organization in 1975. It is the certain system of distribution and grouping of diseases and pathologic states according to special criterions, namely: the etiology, morbid anatomy, basic localization of changes in organs and systems. The statistic classificaton of diseases is used for analysis of disease incidence and mortality of population in differ-ent countries over the world.DeathDeath is extinction and stopping of vital functions of organism. This is a process having certain dynamics. The principal periods of dying are called "terminal states". They are: 1) pre-agony, 2) terminal pause, 3) agony, 4) clinical death (reversible), 5) biological death (irreversible).Pre-agony has different duration (hours, days). Dyspnea, drop in arterial pressure, tachycardia, disorder in con-sciousness characterize this period. Pre-agony is followed by agony.

Agony (from the Greek word "agon" - struggle) is charactarized by the progressive ex-unction of vital func-tions, namely, by disordered activity of the central nervous system and disturbances in all the vital functions of the organism - irregular and intermittent respiration, weakened heart action, relaxation of the sphincters, drop in temperature and, not infrequently, loss of consciousness. Agony preceeds clinical death and may last from sev-eral minutes to hours.Clinical death is the state when all vital functions are stopped and the signs of life are disappeared. This state is characterized by the deepest depression of the functions of CNS. The metabolic processes are noticeably dis-turbed, the energy reserves become depleted, but the changes in the tissues are still reversible, for which reason restoration of the vital functions of the organism is sometimes possible during clinical death which lasts 5-6 minutes. But with the appearance of irreversible changes in the tissues, which first occur in the higher parts of CNS, a state of biological or true death sets in.

GENERAL PATHOGENESIS

The study of pathogenesis requires investigation of all stages in the development of pathologic

phenomena, their succession and interconnections. The basic factors determining the character

and peculiarities of a disease are: (i) the character of cause, (ii) the localization of primary dam-

age, (iii) the character of primary damage.

The significance of the localization of primary damage depends on (i) the vital importance of

the damaged organ and (ii) the character of afferent nerve imputation from its receptor field.

The main kidns of primary damage which influence the peculiarities of the development and

the course of a disease are:

1) structural damage to tissues and organ,

2) the excessive stimulation of receptors of the damaged tissue;

3) generalized disturbances in metabolism;

4) terimary disorders in the activity of regulatory systems.

A disease is the affection of total organism often characterized by predominant localization of

damages to one or another organ. In some cases a damages to one or another organ. In some

cases a disease may begin with local injuries, in other ones pathologic changes in tissues of or-

gans arise after the appearance of the general manifestations of the disease.

Lozalization of pathologic changes is determined by:

1) application of primary action of the causative factor;

2) the ways of releasing of toxic substances from the organism;

3) the changes in reactivity of organs;

4) the peculiarities of biochemical processus in tissues and organs.

The significance of the site of penetration of pathogenic agents. The gate of entrance of the

pathogenic agents and the site of their initial effect play a very important part in pathogenesis.

For example, the perentration of gonococci to the urethral mucosa gives rise to gonorrheal ure-

thritis, whereas the action of the same microorganism on the mucosa of the eye produces gonor-

rheal conjunctivitis (blennorrhea). Subsequently these two processus greatly differ in their de-

velopment. Of the factors that determine the mechanism of action of pathogenic stimuli an im-

portant part is apparently played by the anatomophysiological and biochemical properties of the

organs and tissues, their functional state and the characteristics of their receptor fields.

Pathologic processes predominantly affect particular organs, not only according to the point of

entry of the pathogenic agent, but also to the physiological pecularities of the entire organism.

For example, osteomyelitis (the inflammation of bone marrow and bone marrow and bone)

most frequently begins in the metaphyses of tubular bones. This is accounted for, not only by

the characteristics of capillaries, but also by the regulation of the blood flow which provides an

abundant blood supply to the given part of the bone where the best conditions are apparently

created for contact of the tissue with the toxins of bacteria brought in by the blood flow.

Sometimes the effect of the etiologic factor is predominantly manifested in the parts of the or-

ganism which suffered injury. By damaging tissues, injuries produce nutritional and metabolic

disorders in them, reduce the general resistance of the organism and facilitate the penetration

and spread of the noxious agent in it. Thus, and injury to a lung may stimulate the development

of purulent inflammation in it, an injury to the limbs - development of tuberculosis of bones.

The Spreading of pathogenic agents.

To disclose the pathogenesis of diseases and understand their development it is also necessary

to investigate the spread of pathogenic agents in the organism after their penetration into its in-

ternal environment. As a result of the spread of pathogenic agents the pathologic process may

involve the adjacent and, not infrequently, distant organs and tissues. The pathogenic agents

may spread:

1) the extension and contact,

2) through the vascular (circulatory and lysphatic) system and

3) through the nervous system.

The spread by extension occurs as a result of the action of the pathogenic agent, which affects

one part of a tissue on the adjacent normal part, for example, the spread of herpes over the skin

or of infection along the urinary tract.

Closely resembing the aforedescribed route of spread is the intracanalicular spread, for exam-

ple, along bronchi or excretory gland ducts. Thus infected masses preading along bronchi from

some tuberculous focus in the lungs cause the development of a pathologic processes in other

parts of the Jungs.

The spread may also be a result of contact of an affected surface with a healthy surface. In in-

flammation of the gallbladder the inflammatory agent sometimes affects the serous coat of the

stomach causing its inflammation (perigastritis).

The penetration of pathogenic agents (microbes, toxins and poisons, cells of malignent tumors,

etc.) into the blood stream leads to their spread throughout the organism. For example, after af-

fecting the entire organism and weakening its defence mechanisms bacteria and toxins may at

first gain entrance into the tissue fluid and then through the lymphatic vessels into the lymph

nodes where they may be stopped or carried further by the lymph into the venous system. This

route of spread through the lymphatic system is called lymphogenic.

In other cases bacteria and toxins penetrate, for example, together with emboli into the blood

stream and are quickly transported by the latter; this route of spread by the circulatory system is

known as hematogenic. Microbial metabolites or tissues catabolites may spread from the focus

of infection and cause general intoxication and a febrile process. Some infectious agents, for

example, the rabies virus or tetanus toxin, which act selectively on nervous tissue, spread along

nerve trunks.

The spread of pathogenic agents must not be conceived mechanistically, as a phenomenon de-

pending only on the direction of the vessels or nerves. Here we have a complicated biological

process, i.e. a complex of unstable, continuously varying physiological states of the organism,

particularly the environment into which the pathogenic principle gains entrance.

Interrelation between the local and the general phenomena in pathogenesis. The pathologic

process may at first manifest itself in the injury of the tissue at the point of the application of

the stimulus mechanical, chemical, thermal, infectious, etc. The process gives rise to distur-

bances in metabolism and the structure of the tissue.

Pathologic processes are never stictly localised. On the one hand, the character of their develop-

ment is determined by the properties of the organism as a whole; on the other hand, once aris-

ing, these processes also affect, in their turn, the entire organism. Such a local pathologic

process as inflammation depends on its origin and development on the general condition of the

organism and is a local expression of its general properties. For example, furunculosis is often a

result of nutritional and metabolic disorders and concomitantly lowered immunity.

Other diseases involving changes in the entire organism also produce local changes, such as

functional and structural disturbances in some particular organ. Thus, typhoid fever, although a

disease of the entire organism, is characterised by peculiar changes in the small intestine. Ath-

erosclerosis which develops as a result of general metabolism disorders is marked by changes

in the walls of large arteries.

Owing to the integrity of the organism and the interaction of its parts, local processes must not

be considered apart from the entire organism. At the same time, originating in a particular part

of the organism, at a certain stage of its development the pathologic process becomes the start-

ing point of new relations between the local and the general and affects of entire organism. For

example, an inflammatory focus evokes a general leukocyte reaction and visibly alters the sen-

sitivity of the entire organism to foreign proteins and infectious agents. The mechanisms of in-

fluence of local process on the entire organism:

1) reflex mechanism: CNS receives from the receptors signals pertaining to the" state of the or-

ganism internal environment and affecting state of CNS,

2) humoral mechanisms: the damaged tissue releases the biologically active substances, me-

tabolites, changed proteins, toxins of microbes and etc., which affect the activity of regulatory

systems (CNS, endocrine system).

The mechanisms of inluences of the entire organism on the local processes:

1) CNS realizes the functional and trophic influences on the damaged tissue and also affects its

blood supply,

2) hormones influence the metabolism and functions of damaged tissue.

Thus, the local and the general must be understood in their dialectical unity. Disclosure of these

interrelations makes it possible to gain a deeper insight into the pathogenesis of the disease.

Correlation of function and structural manifestations of disease.

Disease always manifests itself in functional disorders while structural changes often are not re-

vealed. Lack of disparity between stuctural and functional disturbances may be explained by

1) slight expression of the structural changes,

2) their reversibility,

3) local character of the structural changes.

4) unequal significance of different organ parts for its function,

5) impossibility to reveal some structural changes in cells and tissues,

6) development of compensatory reactions.

On the basis of the expression and prevalence of structural or functional changes organic and

functional diseases are distinguished. An organic disease is characterized by expressed struc-

tural disorders which can transform into steady irreversable changes. Functional diseases de-

velop without marked structural disorders and usually deal with temporary disturbances in ner-

vous and humoral regulation of functions.

Destructive and defensive mechanisms in pathogenesis.

Each disease manifests itself in the destructive and defensive mechanisms. The destructive re-

actions arise in result of the direct action of the causative factor and defensive ones - in the re-

sult of mobilization of regulatory systems and development of adaptation reactions. The defen-

sive functions of the organism manifest themselves variously: in production of immunity (in in-

fectious diseases), in elimination of the pathogenic agent (for example, in the vomit, urine,

sweat), in bleading of the tissue defect (in traumas, wounds), etc.

The defence reactions during different stages of the development of a disease are not equally

strong and sometimes reach an intensity which may even prove harmful to the organism. For

example, proliferation which is usually one of the defence mechanisms may be as intensive as

to prevent the repair of the damaged part of the tissue; fever which is conductive to elaboration

of immunity becomes dangerous to the nervous and cardiovascular systems when the tempera-

ture rises too high; vomiting occurring in many forms of intoxication helps to rid the organism

of toxic products, but intractable vomiting in toxemia of pregnancy may imperil life.

An important role in the defense physiologic reactions of the organism of higher animals and

man is played by the higher divisions of the CNS, especially the cerebral hemispheres, the ap-

paratus which adjusts and regulates all functions of the organism.

The role of the CNS in the processes of restoration of functions impaired by disease is particu-

larly easy to observe in cases of deep anesthesia or cerebral trauma, which results in

diminished efficiency of the organism and reduces of compensatory reactions in cases of in-

flammation; proliferation and regeneration of damaged tissue notically decrease; after the loss

of blood restoration of blood pressure is retarded; in disorders of cardiac activity hypertrophy of

the heart muscle develops fully and the blood circulation is impaired.

Main mechanisms of pathogenesis

The main known mechanisms of pathogenesis are follows: nervous, hormonal, humoral, im-

mune, genetic.

Importance of nervous mechanisms in pathogenesis. The organism is adjusted to its en-

vironment by means of its nervous system which controls the functions, blood supply and

metabolim of all its organs and tissues. By acting on the organism of higher animals and men

the pathogenic agent first stimulates the nerve endings (extero- or introceptors) whose sensi-

tivity is many times as high as the sensitivity threshold of the other tissue elements. The re-

ceptors are the initial link of reflex arcs by means of which the organism reacts to the patho-

logic influences exerted on it by its external or internal environment

The direct and limited disturbances, owing to the simultaneous stimulation of the receptors

which send signals to the CNS, lead to a general reaction of the organism, based on the reflex

mechanism, which can be observed, for example, in the experiment with the production of a

burn. The action of a thermal agent applied to the surface of the body causes injury of the tissue

and a simultaneous reflex elevation of arterial pressure, change in hemopoiesis and metabolism,

disturbance in respiration, etc. The reflex mechanism is very important in the pathogenesis of

trophic disorders of the skin and (oral) mucosa.

In addition to reflex action, pathogenic stimuli may affect the CNS directly; these stimuli may

be carbon dioxide accumulated in the blood or microbial toxins or toxic metabolites.

Depending on the etiological factor, the site of its action and properties of the organism, the

pathogenesis of a disease may be connected with changes in the functions of various parts of

the nervous system - from peripheral endings of afferent nerves to the cerebral cortex. Thus,

respiratory disorders may arise in one case as a result of stimulation of the peripheral endings of

the pulmonary branches of the vagi, in another - as a result of injury to the medulla oblongata or

certain parts of the diencephalon, and in still another - as a result of a disturbed function of the

cerebral cortex (for example, dyspnea during excitement or disturbance in higher nervous activ-

ity).

In other words, the pathologic process may be engendered in different parts of the organism.

The sequence and degree of the functional disorder of the particular part of the nervous system

are of certain importance in the character and rate of development of the given pathologic

process. However, owing to reflex activity, the pathologic process in the end inevitably in-

volves other divisions of the nervous system, parts of which are most intimately interconnected.

To elucidate the participation of the higher parts of the nervous system in the pathogenesis of a

disease it is also important to study its basic regularities: typological properties, correlation of

the processes of excitation and inhibition, phenomena of parabiosis (after We-densky), domi-

nant (Ukhtomsky), trace reactions, etc.

An important part in pathogenesis is played by disturbances in the interrelations between the

CNS and the internal environment of the organism. The dependence of the functions of the in-

ternal organs on the activity of the higher parts of the CNS was repeatedly observed by clini-

cians. On the one hand, we know about the effects of various emotional experiences on the

heart action, respiration and digestion; for example, we know of cases of cardiac paralysis

caused by distressing experiences, changes in the respiratory rhythm due to sudden fright, di-

gestive disorders connected with mental depression and chronick lack of appetite. On the other

hand, there are very well known examples of bodily afflictions overcome by positive emotions.

By his many years of studies of the cerebral cortex activity Pavlov demonstrated that the func-

tions of the internal orgnas, regulated by subcortical structures, also had their "cortical repre-

sentation". For example, be observed a prolonged disturbance in the motor and secretory func-

tions of the stomach of dogs as a result of disturbances in the functional state of the higher parts

of the brain caused by a clash of the processes of excitation arid inhibition. Disorders of higher

nervous activity were also shown to play an important part in altering the functions of other in-

ternal organs - gastric secretion, bile secretion, blood pressure, excretion of urine,

hematopoiesis.

Other researchers have showed the possibility of forming conditioned reflexes involving the

functions of the internal organs and the importance of interoception of these processes.

They demonstrated the possibility of conditioned reflex polyuria (passage of an excessive

quantity of urine) and anuria (arrest of urinary output), conditioned reflex bile secretion, con-

traction of the spleen, vasoconstriction and vasodilatation, changes in respiration, metabolism,

etc. These studies formed the basis of the concept of feedback relations between the activity of

the cerebral cortex and the function of the internal organs (corticovisceral relations, according

the internal environment of the organism, but in its turn is also under continuous influence of

impulses coming from the periphery.

As soon aL, impulses from the extero- and interoceptors reach the cerebral cortex, the latter sets

off a complex process of analysis and synthesis and creates the correlations between the pro-

cesses of excitation and inhibition which determine the character of its influence on the func-

tions of the internal organs. Disturbances in the normal relations between the cortex and subcor-

tical region not infrequently underlie a number of diseases.

These data have shaped new conceptions of the role of the CNS in the pathogenesis of a mem-

ber of diseases, for example, ulcers, hypertensive vascular disease, bronchial asthma and coro-

nary insufficiency.

The influence of the higher part of the CNS is exerted through its lower parts. The pathogenesis

of diseases of the internal organs may also be primarily connected with disturbances in the

functions of the subcortical region, particularly the region of the subcortical region, particularly

the region of the hypothalamus which contains the centres that regulate, by means of efferent

neurons, the processes operating in the internal environment of the organism.

Studies in the physiology of the cerebral hemispheres have established the role of cortical inhi-

bition as a defence reaction of exhaustion and great damage to or destruction of nerve cells.

This inhibition is conducive to restoration of cortical activity and is, according to Pavlov, a

safeguard. It often comes into play in the course of various pathologic processes as a defence

reaction to noxious agents and the damage caused by them, for example, in cerebral anemia,

various forms of poisoning and infectious diseases.

Production of defensive inhibition underlies the use of prolonged natural or artificial (induced

by medication) sleep (if the latter closely resembles natural sleep). Prolonged sleep therapy is

now indicated in some cases of traumatic shock, hypertensive vascular disease, ulcers, etc.

Humoral mechanisms, especially neuroendocrine and endocrine regulation, also constitute a

very important link in the regulation of functions. Through their various functions endocrine

glands determine, in close interaction with the nervous system, the reaction of the complex or-

ganism to the action of the stimulus. For example, disorders of urinary output may occur

through subcortical vegetative centres and their connection with the posterior lobe of the hy-

pophysis which secretes an antidiuretic hormone that influences water reabsorption in the kid-

neys.

With the evolutionary development of organism the neuroendocrine relations assume increasing

importance in pathologic reactions. The cortico-diencephalohypophyseal correlations and the

hypophyseal-adrenal function closely connected with them play a particularly important role in

higher animals and man. This system actively praticipates in the adaptability of the organism, in

its nonspecific reactions to the action of any pathologenic stimulus.

In addition to the hormones produced by endocrine glands, tissue hormones may also take part

in the pathogenesis'of disease; these hormones, for example, active polypeptides and proteins,

histamine, acetylcholine, serotonin are physiologically active substances. They may also partic-

ipate in disturbing the regulation of functions, which is often discovered in pathologic pro-

cesses.

Recovery (convalescence)

Recovery is the active process consisting of the complex of reactions which (i) arise in the Be-

ginning of disease and (ii) provide normalization of the organism's functions and (iii) compen-

sation of disturbances in its relationships with external environment.

Mechanisms of the recovery include:

1) elimination of the cause of the disease,

2) disruption of the cause-and-effect relations,

5) enchancing of defensive and adaptive reactions,

4) formation of compensatory reactions,

5) adaptive changes of the regulatory system functions.

The main mechanisms of restoration of destroyed functions in the organism are the compensa-

tion (i) and regeneration (ii).

Compensation makes up structural and functional disorders.

Mechanisms of the compensation:

1. involving of the reserve possibilities of organ;

2. increasing in the function of the vicarious organ;

3. change of metabolism and increasing in activity of normal part of the organ or replacement

of one part of a single functioning system by another.

The main stages of the development of compensation: (i) formation, (ii) fastering, (iii) exhaus-

tion.

Regeneration is the kind of compensation characterized by structural repair of damaged organ.

Regeneration is called true if it develops by means of cell proliferation. Regeneration •s called

partial if it develops by means of hyperthophy of preserved cells in the damaged organ.

The main principles of treatment of diseases.

The main tasks of disease treatment are:

to prevent the mortal outcome

to achieve recovery;

to restore capacity for work and social useful -1 activity.

Medical measures providing the elimination or neutralization of the causative factor are called

etiotropic therapy.

Medical measures acting on mechanisms of disease, development and also providing elevation

of organism's resistance and restoration of its functions are called pathogenetic therapy

These measure correspond to the recovery mechanisms.