system
Given the following post, respond as if you're commenting on Reddit:
human
What exactly is 'shock', and how does one die of it?
gpt
"Shock" is medically known as Hypoperfusion, which is inadequate perfusion of oxygen to the body systems. 

There are a number of different ways that hypoperfusion can occur, such as a sudden, massive loss of blood (known as hypovolemic shock). Edit: removed some incorrect information here. See the clarifying comment below.

In simplest terms, shock is when oxygen doesn't get to the vital body systems necessary to support life. Without oxygen, cells (especially brain cells) will die very quickly.