Regeneration

Regeneration (pathology) - restore the integrity of tissues, violated any painful process or external detrimental effect. Recovery is due to the propagation of the neighboring cells, filling young cells of the defect and the subsequent transformation into a Mature tissue. This form is called reparativee (recovery) recovery. Thus there are two options regeneration: 1) the loss is indemnified cloth of the same type that killed (regeneration); 2) loss replaced by young connection (granulation) cloth, turns into scar (partial regeneration), which is not regeneration in the proper sense, and the healing of a tissue defect.
Regeneration precedes the release of this area from the dead cells by enzymatic their fusion and absorption in the lymph or blood or by phagocytosis (see). Products melting is one of the promoters of reproduction neighboring cells. In many organs and systems, there are sites whose cells are the source of reproduction of cells regeneration. For example, a bone this source is periosteum, whose cells are reproducing themselves, constitute the first osteology cloth, later turning into a bone, in the mucous membranes of cells deep glands (crypt). Regeneration of blood cells occurs in the bone marrow and out of it in the system reticular tissues and its derivatives (lymph nodes, spleen).
The ability to regenerate have not all fabrics and not to the same extent. So, heart muscle cells are not capable of reproduction, culminating in the formation of Mature muscle fibers, so each defect of the muscles of the myocardium is replaced by scar (in particular, after a heart attack). When the death of brain tissue (after hemorrhage, arteriosclerotic softening) the defect is not replaced nervous tissue, and is formed of the frame.
Sometimes occur when the regeneration of tissue structure differs from the original (atypical regeneration) or its volume exceeds the volume of dead tissue (hyperresonance). Such a regeneration process may lead to tumor growth.

Regeneration (lat. regenerate - revival, restoration) - the restoration of the anatomical integrity of an organ or tissue after the death of the structural elements.
Under physiological conditions regeneration processes taking place continuously with different intensity in different organs and tissues, respectively intensity ugiwania cellular elements of that organ or tissue and replacing them with the newly formed. Steadily replaced by the formed elements of the blood, the cells surface epithelium of the skin, mucous membranes, gastrointestinal tract, respiratory tracts. Cyclic processes of female genital sphere lead to rhythmic exclusion and updating of the endometrium by its regeneration.
All these processes are physiological prototype pathological regeneration (it is also called reparative). Features of development, the course and outcome of reparative regeneration are defined by the sizes of the death of the tissue and the nature of pathogenic influences. The latter is especially necessary to keep in mind, since the conditions and causes of death of tissue, are essential for the regeneration of the process and its outcomes. So, for example, the specific nature have the scars of skin burns, different from the scars of different origin; syphilis scars rough, lead to deep vtjazhenija and mutilation of the body of it. D. unlike the physiological regeneration, reparative regeneration covers a wide range of processes leading to compensation defect caused by the loss of fabric due to its damage. There are full of reparative regeneration - restitution (substitution of the defect cloth of the same type and the same structure as that of the deceased) and incomplete reparative regeneration (filling defect cloth with large plastic properties than lost, i.e. conventional granulation tissue and connective tissue with further conversion it into scar). Thus, in pathology under the regeneration often mean healing.
With the concept of regeneration is also the concept of the organization as the basis of both processes are General patterns of tumor tissue and the concept of substitute, i.e., displacement and substitution newly formed tissue tissue predshestvovali (for example, substitute clot fibrous tissue).
The degree of completeness of regeneration is determined by two main factors: 1) regeneration potency of this tissue; 2) the volume of the defect and the single or the diversity of species of dead tissue.
The first factor is often associated with the degree of differentiation in this tissue. However, the concept of differentiation and the content of this term is very relative, and comparison of tissues on this topic with the establishment of quantitative grading of differentiation in functional and morphological relations impossible. Along with tissues with a high regenerative potency (for example, the liver tissue, mucous membranes, gastrointestinal tract, the blood-forming organs and others), there are bodies with negligible potential for regeneration, in which regeneration is never completed a full restoration of the lost tissue (for example, the heart, the Central nervous system). Extremely high plasticity have connective tissue elements of the walls of the smallest blood and lymphatic vessels, peripheral nerves, reticular tissue and its derivatives. So plastic irritation, which is a trauma in the broad sense of the word (i.e. all its forms), first of all and most fully stimulates the growth of these tissues.
The volume of dead tissue is essential to the completeness of regeneration, and empirically more or less known quantitative border tissue loss for each body, determining the degree of recovery. Think for a complete regeneration not only is the amount as a purely quantitative category and complex diversity of dead tissue (this applies especially to the death of tissue caused toxicoinfections impacts). To explain this fact should, apparently, to appeal to the General regularities of stimulation plastic processes in conditions of a pathology: stimulants are themselves products of tissue death (hypothetical "necroharmonic", "mitogeneticheskie rays, Trevone', and so on). Some of them are specific stimulants for cells of a certain type, other, non - specific to promote the most plastic fabric. Non-specific stimulators are decay products and activity of leukocytes. Their presence reactive inflammation, developing always with destruction not only of parenchymatous elements, but soudanese stroma, contributes to the reproduction of most plastic elements - connective tissue, i.e. development in the end of the scar.
There is a General scheme of sequence of regeneration processes, regardless of the area where it happens. In conditions of a pathology regeneration processes in the narrow sense of the word and healing processes are of various kinds. This difference is determined by the character of the death of the tissue and electoral orientation of the action pathogenic factor. Clean form of regeneration, i.e. the restoration of fabrics, identical to the lost, are observed in cases when under the influence of pathogenic impact die only specific lung elements of the body under the condition of their high regenerating potency. An example of this is the epithelium regeneration renal tubular selectively damaged by toxic effects; regeneration of epithelial mucous membranes with desquamation; regeneration of alveolocytes easy when desquamative Qatar; the epithelium of the skin; regeneration of the endothelium of blood vessels and the endocardium and others In these cases, the source of regeneration are remaining cellular elements, reproduction, maturation and differentiation, which leads to the complete replacement of missing parenchymal cells. When the death of complex structures to restore the lost tissue is of particular areas of the body, which is a kind of centers of regeneration. In the intestinal mucosa, the endometrium those centers are glandular crypt. Their reproducing cell cover the defect first one layer of undifferentiated cells that are then differentiated cancer and restored the structure of the mucous. Osseous system in such a centre regeneration is periosteum in the top flat epithelium - malpighian layer in the system of the blood, bone marrow and extramedullary derivatives reticular tissues.


The General law of regeneration is the law of development, according to which in the process of tumors arise young undifferentiated cell derivatives, in the future, passing the stages of morphological and functional differentiation up to formation of Mature tissue.
The death of the sections of the authority consisting of a complex of various tissues, causing reactive inflammation (see) on the periphery. This adaptive act as inflammatory reaction is accompanied by redness and increased tissue metabolism, which contributes to the growth novoobrazovany cells. In addition, cellular elements inflammation of the group getoperation are plastic material for tumors of the connective tissue.
In pathology often anatomical healing is achieved by granulation tissue (see) - stage tumors fibrous scar. Granulation tissue develops in almost all of reparative regeneration, but the degree of its development and the final outcomes vary widely. Sometimes it is hardly distinguishable microscopic examination of the delicate parts of fibrous tissue, sometimes coarse thick strands galinadiamond brigittines scar tissue, often exposed to calcification (see) and of ossification.
In addition to the regeneration potency of this tissue, the nature of its defeat, volume, important in the recovery process have common factors. These include the age of the subject, character and habits, General reactivity of the organism. Disorders of innervation, beriberi ordinary course of reparative regeneration distorted that most often expressed in slowing down the process of regeneration, lethargy cellular reactions. There is also the concept of fibroplastic diathesis as constitutional features of an organism to respond to various pathogenic irritation increased formation of fibrous tissue, which is manifested by the formation of keloid zone (see), peritoneal commissures. In clinical practice it is important to consider common factors for the creation of optimal conditions of completeness of the recovery process and healing.
Regeneration is one of the most important adaptive processes, which restores the health and survival in extreme circumstances created by the disease. However, as with any adaptive process, regeneration on the famous stage and under certain development paths can lose adaptive value itself to create new forms of pathology. Disfiguring scars, deforming body, dramatically alter their function (for example, scar transformation of the heart valves in the outcome of endocarditis), often create serious chronic pathology requiring special treatment. Sometimes the newly formed tissue quantitatively exceeds the amount of the deceased (superregenerative). In addition, at least the regenerate are the elements of atypism, a sharp expression of which is the stage of tumor development (see). Regeneration of separate organs and tissues - see the relevant articles about the organs and tissues.