It involves a controlled sequence of steps in which cells signal self termination. Apoptosis works to keep the body's natural process of cell division or mitosis in check.
There are several instances in which cells may need to be destroyed. Cells may need to be removed to ensure proper development.
For instance, the natural process of menstruation involves the removal of tissue from the uterus.
Cells may also become damaged or undergo some type of infection. One way to remove these cells without causing harm to other cells is through apoptosis.
During apoptosis, a cell triggers a process that will allow it to "commit suicide." In this process, the cell undergoes a reduction in size as its cellular components break down and condense.
Bubble shaped balls called blebs appear on the surface of the cell.
The cell then breaks down into smaller fragments called apoptotic bodies. These fragments are enclosed in membranes so as not to harm near-by cells.
Other cells, known as phagocytic cells, engulf and destroy the apoptotic bodies without causing an inflammatory reaction.
CancerSome types of cancers persist as a result of a cell's inability to undergo apoptosis.
Tumor viruses change cells by integrating their genetic material with the host cell's DNA.
This is a permanent insertion in that the genetic material is never "removed." These viruses initiate the production of proteins that stop apoptosis from occurring.
An example of this can be seen with papilloma viruses, which have been linked with cervical cancer.
Even cancers that do not involve viruses produce substances that inhibit apoptosis and promote uncontrolled growth.