Atrophy

Atrophy is to reduce the volume and weight of body tissue with reduction function.
When atrophy occurs reducing the size parenchymal cells or reduction of their number due to the fact that tissue cells are dying faster than normal, and their decline is not fully compensated by the formation of new ones. Atrophy should be distinguished from hypoplasia, in which the body is reduced as a result of violations of its development.
There are atrophy of the physiological and pathological. Physiological include atrophy of the thymus gland in adults, atrophy of the sex glands, bones, muscles, skin, intervertebral cartilage and other organs and tissues in old age. Pathological atrophy occurs when insufficient flow in the body or body of nutrients (for example, when starvation) or violations of their learning at various painful conditions (cancer of the stomach, some infectious diseases, disorders of the endocrine organs, the Central nervous system and others). Such atrophic processes can be common and limited.
When common atrophy (see Cachexia) weight loss occurs due mainly to reduce the amount of adipose tissue and skeletal muscle. Fatty tissue becomes ocher-yellow, sometimes impregnated serous fluid. Skin becomes thin and dark. In the organs (heart, liver, muscles and other) accumulated brown pigment (brown atrophy); the amount bodies decreases.
Limited atrophy may occur when the disruption of the body with nerves (trauma, inflammation, tumor spreading) - neurogenic atrophy. Atrophy of the body comes also extended inactivity due to circulatory disorders (for example, brain or kidneys), mechanical pressure (bone loss in pressure on her cysts or tumors), excessive physical (radiant energy) and chemical exposure. Atrophy may be accompanied sclerosis body - the growth of connective tissue, making it thick and wrinkled. Sometimes simultaneously with atrophy parenchyma is growth in the bodies of fat tissue; the size of the body is not reduced.
In some cases atrophy - reversible process and in the elimination of causes atrophy, is restored to the original condition of the organ and its function. Recovery does not occur only with advanced atrophy. Cm. also Degeneration of cells and tissues.

Atrophy (gr. atrophia, from atropheo - wasting away, fade) - reducing the volume of tissue or organ under the influence of different impacts. Atrophy - process purchased, i.e. when it decreases the amount structures, till developed normally in accordance with the specific physiological and age peculiarities of the organism. This is the fundamental difference atrophy from the formally similar processes hypoplasia (see). From atrophy in her pathological sense, one should distinguish between physiological age involution of the body, such as age atrophy (involution) the thymus gland. On the border with physiology is senile atrophy of many organs (skin, bones, and other).
In the basis of atrophy is the reduction of the sizes and later the major cellular elements of the body. Wasting cells remain the main structural elements of the kernel with the cytoplasm (without visible change their tinctorial features on General methods of colouring). This creates the impression of a purely quantitative volumetric processes A. without deep violations of cell metabolism, unlike tissue dystrophy. In reality A. can be considered as a kind of tissue dystrophy with relatively slow development, where the prevalence of catabolic processes over anabolic leads to the gradual reduction of the sizes of cells until their disappearance. Degenerative nature A. emphasizes a common education in wasting cells brown pigment lipofuscin - product violated lipidnog-pigmentary exchange, giving the affected organ brown (brown atrophy of the liver, myocardium). Cytological and electron microscope study reveals a number of structural changes in the organelles in the cytoplasm and in the nucleus of cells exposed A. Ordinary uneven coverage atrophic process of the cells of the affected organ, and the cytoplasm and nuclei of individual cells creates large cell polymorphism.
A. characterized not only reduced volume and weight of the body, but also a change in the quantitative relationships between its various elements. Factors atrophy, causing havoc to the parenchyma of the authority not to act on stroma, and it remains unchanged (sometimes even growing quantitatively). Therefore, parenchymatous organs (liver, spleen) at A. buy wrinkled appearance, edge liver Ostrovsky consists of connective tissue. The vessels on the surface of the heart when it is A. are tortuous, corkscrew view, because of their length becomes too large for the reduced size of the authority. Trofimovna mucosa (stomach, intestines) thinned, deprived of normal folding, stomach histologically States and morphological reconstruction, bringing the structure of the mucosa to the structure of the intestinal mucosa ("interesate" the mucous membrane of stomach). Fatty tissue (especially epicardial) at the degree of atrophy impregnated serous fluid and acquires sizepolicy (the so called serous A. fatty tissue).
The causes of pathological atrophy varied, but they all involve malnutrition organ or tissue. The most important of them are: prolonged mechanical pressure on tissues, insufficiency of blood circulation to the body, General cachexia, trophic violations of innervation, the fall of the functions of an organ or tissue (called A. from inaction), violations of neurohumoral regulation tissue trophism. Cm. also Degeneration of cells and tissues.