How Apoptosis Occurs in Your Body

Why Some Cells Commit Suicide

Cancer Cell Apoptosis
This colored scanning electron micrograph (SEM) shows a cancer cell undergoing programmed cell death, or apoptosis. Credit: Steve Gschmeissner/Science Photo Library/Getty Images

Apoptosis, or programmed cell death, is a naturally occurring process in the body. It involves a controlled sequence of steps in which cells signal self-termination, in other words, your cells commit suicide. 

Apoptosis is a way for the body to keep checks and balances on the natural cell division process of mitosis or continued cell growth and regeneration.

Why Cells Undergo Apoptosis

There are several instances in which cells may need to self-destruct.

In some situations, cells may need to be removed to ensure proper development. For example, as our brains develop, the body creates millions of more cells than it needs; the ones that do not form synaptic connections can undergo apoptosis so that the remaining cells can function well.

Another example is the the natural process of menstruation that involves the breakdown and removal of tissue from the uterus. Programmed cell death is necessary to start the process of menstruation.

Cells may also become damaged or undergo some type of infection. One way to remove these cells without causing harm to other cells is for your body to initiate apoptosis. Cells may recognize viruses and gene mutations and can induce death to prevent the damage from spreading.

What Happens During Apoptosis?

Apoptosis is a complex process. During apoptosis, a cell triggers a process from within that will allow it to commit suicide.

If a cell experiences some type of significant stress, such as DNA damage, then signals are released which cause mitochondria to release apoptosis-inducing proteins. As a result, the cell undergoes a reduction in size as its cellular components and organelles break down and condense.

Bubble-shaped balls called blebs appear on the surface of the cell membrane.

Once the cell shrinks, it breaks down into smaller fragments called apoptotic bodies and sends out distress signals to the body. These fragments are enclosed in membranes so as not to harm nearby cells. The distress signal is answered by vacuum cleaners known as macrophages. The macrophages clean away the shrunken cells, leaving no trace, so these cells have no chance to cause cellular damage or an inflammatory reaction.

Apoptosis can also be triggered externally by chemical substances that bind to specific receptors on the cell surface. This is how white blood cells combat infection and activate apoptosis in infected cells.

Apoptosis and Cancer

Some types of cancers persist as a result of a cell's inability to trigger apoptosis. Tumor viruses change cells by integrating their genetic material with the host cell's DNA. Cancer cells are usually a permanent insertion in the genetic material. These viruses can sometimes initiate the production of proteins that stop apoptosis from occurring. An example of this is seen with papilloma viruses, which have been linked with cervical cancer.

Cancer cells that do not develop from viral infection can also produce substances that inhibit apoptosis and promote uncontrolled growth.

Radiation and chemical therapies are used as a mode of therapy to induce apoptosis in some types of cancers.

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Your Citation
Bailey, Regina. "How Apoptosis Occurs in Your Body." ThoughtCo, Mar. 11, 2018, Bailey, Regina. (2018, March 11). How Apoptosis Occurs in Your Body. Retrieved from Bailey, Regina. "How Apoptosis Occurs in Your Body." ThoughtCo. (accessed March 22, 2018).