Pathophysiology of Cell Injury
CAUSES OF CELL INJURY
Causes of cell injury are summarized into three components. Injury of the cell occurs as a result of:
- A DEFICIENCY of substances that are vital to the cell
- A presence of substances that inhibit with cell function. This is noted in cases of POISONING or INTOXICATION
- The loss of the cell’s structural integrity such as in cases of physical injuries or also termed as TRAUMA.
The life process of a cell is derived from a variety of chemical requirements, need for an energy supply and from its complex metabolism. Deficiency of these factors may contribute to inhibition of cell function hence, causing cell injury. Factors that may produce a deficiency of essential nutrients vital for the cell’s life process are the following:
- Primary nutrient deficiency
A lack of nutrients necessary for cell’s life process is called a primary nutrient deficiency. In cases where an individual is suffering from starvation a lack of dietary energy sources will result to cellular injury. Even in cases where an individual’s diet is adequate and even excessive in providing energy sources but when a certain nutrient is lacking cellular injury would still be the result. For instance, a person who lacks thiamine in his diet will result to damage on the nervous tissue as this vitamin is required for the normal carbohydrate metabolism in the tissue.
- Secondary Nutrient Deficiency
A secondary nutrient deficiency results from the inability of the body to absorb the substances that are present in the diet. In this case, the person’s diet is adequate not only in energy sources but also in vitamins and nutrients. However, there is a problem in the absorption of the substances that will still result to cell injury.
- Genetic defects
Injurious cell deficiencies can also arise as a result of genetic defects. The metabolic pathways of the cell contain substances that synthesized based on the encoded information from the genes that are present in the chromosomes. (See section on Anatomy and Physiology of Cells). Once chromosomes are damaged or injured a decline in metabolic intermediate occurs and the cell function is then compromised due to the lack or deficiency of these intermediates. Aside from that genetic control of metabolism is defective or inadequate when genetic defects are present. Thus, the resulting phenomenon is – CELL INJURY.
Deficiency state leading to cellular injury can also be caused by viral actions. Following infection of a cell by a certain virus, the virus causes the cells to produce new virus particles that are then released from the infected cell. Aside from that, infectious agents utilize the needed nutrients that the cell must use for its processes. Some cells may survive this situation however, a disruption in the cell’s metabolism occurs when a heavy demand for key metabolites in the production of new viral particles that results to cellular injury.