DEGENERATIONS (dystrophy)

Degeneration (dystrophy) is a pathological process due to disturbance of either cellular or tissue metabolism which causes changes in the structure of cells, tissues, etc.

Trophism mechanisms are cellular and extracellular:

cellular: autoregulation (enzymes)

extracellular: transportation systems (blood, lymph); endocrine regulation;

Morphogenetic mechanisms of degenerations: infiltration: abundant invasion of metabolite

products from the transportation system to the cell followed by their accumulation;

decomposition: destruction of cellular ultrastructure (lipoprotein complex from cellular membranes) with accumulation within a cell;

abnormal synthesis: intracellular synthesis of the substances which are not produced normally (e.g. amyloid);

transformation: formation of products of one type of metabolism from the common primary products, e.g. increased polymerization of glycogen from glucose.

Classification of degenerations

According to the localization:a) parenchymatous (intracellular accumulation),b) mesenchymatous (extracellular accumulation), c) mixed type.

According to the type of metabolism disturbance: a) albuminous (protein), b) fatty (adipose), (lipidosis),c) carbohydrate, d) mineral

According to the origin: a) acquired,b) heriteted.

According to propagationa) general, b) local.

Parenchymatous degenerations

Parenchymatous albuminous degenerations (dysproteinoses)

The modern classification of parenchymatous albuminous

degenerations:

1) hyalin-drop

2) hydropic (edematous, balloon)

Hyalin-drop degeneration

Microscopically: rounded, eosinophilic droplets, vacuoles, or aggregates in the cytoplasm

Macroscopically: not changes

Localizations: kidney, liver, myocardium

Hydropic degeneration

Microscopically: large vacuoles of cytoplasm fluid in the cytoplasm, the nucleus which displaced to the peripheral areas

Macroscopically: not changes

Localizations: kidneys, skin, liver, muscles, nerves

Horny degeneration

abundant formation of horny substance in keratinized epithelium (hyperkeratosis and ichtyosis)

appearance of horny substance in the places where is not found under normal conditions (leukoplakias)

Parenchymatous degenerations

Parenchymatous fatty degenerations

Manifestation

of disturbance of fat metabolism: appearance of fat in the place where it

does not appear under normal conditions (e.g. in the myocardium),

appearance of fat of unusual composition;

increase of fat amount in the places where it is present under normal conditions (e.g. in the fat depots).

Hypoxia - the main cause of fatty degeneration

disturbances in transportation systems (e.g. in patient with chronic cardiovascular and chronic pulmonary insufficiency);

chronic intoxications (e.g. alcoholism);cachexia, avitaminosis; infections (e.g. diphtheria, tuberculosis).

Parenchymatous degenerations

Parenchymatous carbohydrate degenerations

Glycogen metabolism disturbance

increase or reduction in the amount in the tissues where it is present under normal conditions,

its appearance in the areas where it is not present under normal conditions

Storage diseases(enzymopathy)

proteinoses lipidosis

glucogenoses

Thank you for your attention