Apoptosis is a program mechanism of cell death, every cell has a time to live and die, and there are two ways in which they die, by injury or suicide.
If a cell is damage by injury or a toxic substance, the its call necrosis. If this is the case they undergo a seeries of changes, like, they swell becasue of the ability of the plasma membrane to control the passage of ions and water is disrupted. Also, the cell contents can leak out, causing inflammation of the surrounding tissues.
If a cell is induced to commits suicide then it is call apoptosis. When this happens cells shrink, have their DNA and protein in their nucleus degraded, have their mitochondria break down with the reales of cytochrome c. In mammalians cells release ATP and UTP.
These nucleotides bind to receptors on wandering phagocytic cells like macrophages and dendritic cells and attract them to the dying cells.
The phospholipid phosphatidylserine, which is normally hidden within the plasma membrane, is exposed on the surface.
This "eat me" signal is bound by other receptors on the phagocytes which then engulf the cell fragments.
The phagocytic cells secrete cytokines that inhibit inflammation.
There are two reasons why cells commit suicide. One is that there is a need to destroy cells that represent a threat to the organism. And second, is needed for proper development as mitosis is.
Some examples of cell that represent a threat to the integrity of the organism are:
- Cells of the inmune system
- Cells infected with viruses
- Cells with DNA damage
- Cancer cells
i did not knew a lot of apoptosis but i had read about necrosis it is interesting that cells know what to do when they have being contaminated with a toxin or virus. they either be destroy by the virus or it destroy themselves. plus the video help even more to understand how the process is done.
ReplyDeleteUnlike you, I had never really heard about apoptosis. When the book was talking about it I got a little confused because it wasn't in depth. Your post helped me understand a lot. Especially the diagram of how apoptosis works. After reading your post I have learned that the reason the cells "commit suicide" is being one they're trying to stop a threat and two it is sometimes needed for development.
ReplyDeleteAs always it is interesting to me to read about something my body does that I am unaware of. We go through life each day in our bodies however, most of us have no clue what our body is doing. To think that we have cells in our body that take the initiative to commit "suicide" in the thought process of pretty much "utilitarianism" (do what is best for the majority) pretty much is amazing. While reading your blog and watching the video as you can see from my previous statement it is easy to start picturing our insides as a sort of community. All of the different functions work together in order to make one thing work (our body).
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