system
Given the following post, respond as if you're commenting on Reddit:
human
What physically happens to the body in a morphine overdose?

I know that its used in regulation to negate pain but what physically happens to a body when a large amount of morphine is given to kill someone.
gpt
Painkillers (such as morphing, heroin, OxyContin, etc) relax muscles as well. In large enough doses, the person is literally unable to move a muscle, voluntarily or otherwise. 

This means that the diaphragm, which is the muscle used to breathe, cannot contract. The person suffocates because the brain can not activate the diaphragm muscle to contract(breath in). 

In even larger doses, the heart can stop as well, though most people die from suffocation rather than their heart stopping. 

Don’t do drugs, kids.