Help understanding Threads and their scope

[epete]

I have several settimers in a script. I want one of them to be "Critical", and put "Critical" in the settimer function.
1) Is each settimer a complete "thread"?
2) If the settimer is a function, and that function calls other functions, which calls other functions - is the entire thing a single thread that is protected by the parent "Critical"?
3) i.e., will other settimers run during this chain of a "Critical" thread?
4) In essence, I want all other settimers to wait until the critical settimer is done doing it's thing.

[mikeyww]

Why not test it? You could answer all of your questions in just a few lines. Please take no offense; testing seems like a good idea.