In other cases, hypertrophy or hypoplasia is the compensatory mechanism for this situation. The altered cellular activities may lead to metaplasia, dysplasia, or neoplasia because aging cells are more susceptible to destruction of their DNA, RNA and vital proteins. Extremly low temperature is able to form crystals inside the cell. Mild decrease in temperature causes paralysis of vasomotors and an increase in permeability of vessels. Blood viscosity rises proportionally with the lowering temperature and cells are destroyed by hypoxia.
Low temperature acting for a longer time provokes the destruction of myelin in exposed area.
Microthrombi are produced in vessels and they are the cause of gangrene . High temperature increases the permeability of cell membranes. Very high temperature is responsible for the coagulation of vessels and denaturation of vital biopolymers, especially proteins. According to the dose and the way of exposition ionizing irradiation may primarily damage haematopoietic, gastrointestinal or neural tissues. Whole-body irradiation produces nonspecific immunosupression which is the cause of increased sensitivity to infection.