Cell Injury and Cellular Adaptations

Cells are the basic units of tissues, which form organs and systems in the human body. Traditionally, body cells are divided in to two main types: epithelial and mesenchymal cells. In health, the cells remain in accord with each other. In 1859, Virchow first published cellular theory of disease, bringing in the concept that diseases occur due to abnormalities at the level of cells. Since then, study of abnormalities in structure and function of cells in disease has remained the focus of attention in understanding of diseases. Thus, most forms of diseases begin with cell injury followed by consequent loss of cellular function. Cell injury is defined as a variety of stresses a cell encounters as a result of changes in its internal and external environment. In general, cells of the body have inbuilt mechanism to deal with changes in environment to an extent.

Homeostasis of Humanbody

                    Homeostasis is the condition of equilibrium (balance) in the body’s internal environment due to the constant interaction of the body’s many regulatory processes. Homeostasis is a dynamic
condition. In response to changing conditions, the body’s equilibrium can shift among points in a narrow range that is compatible with maintaining life. For example, the level of glucose in blood normally stays between 70 and 110 milligrams of glucose per 100 milliliters of blood. Each structure, from the cellular level to the systemic level, contributes in some way to keeping the internal environment of the body within normal limits.