Cellular Pathology

CELLULAR THEORY

74 both in the sense of an increase in quantity or a qualitative change in the normal chemical ingredients of the cell. In particular, this includes everything related to the pathological deposition and appearance of fatty substances in cells (see Fatty degeneration), the deposition of glycogen in the protoplasm and nuclei of cells (see Glycogen infiltration), the mucinous degeneration of cells, and the appearance of various pigment substances in cells. Most cellular changes expressed in morphological, physical, and chemical disorganization, except those accompanying cell death, are essentially reversible changes; in other words, if the disorganization of the cell has not reached a very significant degree, the cell can return to its normal state. On the other hand, cell disorganization can reach such a degree that the cell already dies (see Necrobiosis). The pathology of the cell also includes various irregularities in cell reproduction, both in the sense of pathological forms of cell division and in the sense of the formation, under various pathological forms of cell reproduction (e.g., in inflammatory and regenerative cell proliferations and especially in tumors), of various abnormal, atypical forms of cells in morphological, chemical, and biological senses (see Anaplasia, Atypical growth and structure, Giant cells, Tumors). In addition to all of the above, concerning the pathological manifestations on the part of the cells themselves, one can also speak of irregularities in entire cell complexes in the sense of changes in the ratio between cells due to a violation of the bond existing between cells, which determines the specific character of cell complexes, i.e., tissues. Depending on various causes acting on cell complexes either mechanically or in the sense of disrupting the normal state of the substance cementing cells to one another, separation of individual cells from the complex occurs (see Desquamation) or complete disruption of the complexity of these cells (see Dissociation). The disruption of ratios between cells can also be expressed in the phagocytosis of some cells by others, for example, the engulfment of erythrocytes, leukocytes, and lymphocytes by reticular and endothelial cells in lymph nodes, the spleen, and follicles, or the phagocytosis of some epithelial cells by others in a cancerous tumor. The functional significance of pathological changes in cells varies. While cell death and severe degrees of degeneration result in the complete cessation of cell functions, minor cell disorganization may lead only to a weakening of its function, as is observed in the majority of degenerations. Some pathological changes in cells (e.g., hypertrophy) may be accompanied by an enhanced function. Finally, in a number of cases, a qualitative impairment of the functions of pathologically altered cells may take place (e.g., the production of abnormal secretions and incretes in glandular cells, a complete perversion of the biological manifestations in the cells of certain tumors). A. Abrikosov.