: Why do human body respond in a “laugh”?

Question

I am assuming that laughter is body’s response to something funny, because we can’t control it. Even if we want to suppress it, it will eventually come out.
When we experience something funny or humorous, what exactly happens in the body biologically that causes it to respond in a way we call “a laugh”?
I’m asking biological terms. For example, sometimes when we’re (our muscle is) weak, it responds by muscle twitches which we can’t control.
So what happens in when experience humour? How the body/the brain perceives that situation which triggers the laughing response, something which can’t be controlled?

In: Biology