Alteration in Biology

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Alteration in Biology


changes in the structure and function of cells, tissues, and organs in response to harmful outside influences (mechanical, thermal, electrical, chemical, and others).

Alteration develops gradually. In its first stages its manifestations are reversible, but prolongation of the effect of the harmful agents may bring about the death of cells and tissues. Structural damage in alteration—paranecrosis—is due to changes in the state of the cellular colloids. Alteration of irritable tissues—nerve tissue and muscle tissue—is accompanied by changes in irritability. What is termed lesion potential occurs in response to the increased permeability to ions of cellular membranes in the altered region. This brings about the appearance of lesion currents.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.