system
Given the following post, respond as if you're commenting on Reddit:
human
What do living organisms do to prevent bacteria from decomposing them that dead organisms are unable to do?

Basically why does decomposition begin after death?
gpt
Our bodies form many barriers that stop bacteria from entering our tissues. Even though we have bacteria on our skin, in our gut and many other places, we have very specialized cells lining these areas. They defend our bodies by numerous mechanisms: secretions that capture bacteria, cilia that push bacteria away from sensitive areas, VERY tight connections between cells that does not allow the passage of bacteria, and defence cells that ingest bacteria and bind antigens are some of these defences. When we die, our cells will also die as our heart stops and oxygen is no longer being delivered to the tissues. as the cells die, they can no longer perform these defensive functions. they may also lyse, releasing proteins and other molecules which the bacteria can thrive on. Consequently the bacteria and other microbes can cross our barriers and invade our bodies.