Auto Parts: Parking brake, rear brakes, rear wheels

Question
Hi,

I have two questions.  
Firstly, I have been told that the parking brake is on the same system as the regular brakes you use when using the pedal.  I found this to be odd.  I have been told (in the past) that should my regular brakes fail for some reason that I should pull up on my parking brake and it will help.  This is conflicting to what I recently heard about the two being connected and if one fails the other fails as well.  
The other question I have is I left my parking brake on while driving ....I crinched and wondered what could be causing my car to not have the pick up it had before...then I noticed the parking brake was on.  What if any damage could I have caused?  Would it have only been damage to the brake ....just some wearing?  Or could I have cause some major damage?  I had it on for about 5 minutes of driving and pushed on the gas a little because it was going slower than normal...I noticed the brake being on before getting on the highway however which is a good thing.

Thank you for your expertise,
Shelly  

Answer
    In the old days, the parking brake used the same parts as the regular brakes, but only acted on the rear wheels.  There are some cars today, although only a few (such as the Explorer) that use a separate parking brake shoe or pad.  The only damage you may have done is to overheat the rear brakes, causing them to wear out too soon.  It all depends on how long you left the parking brake on and how hot they got.  If the car still stops OK, then you are probably in the clear.  Next time you have your car serviced, get them to check the rear brakes.  But don't tell them what you did.  If you do, they'll for sure try to sell you new brakes, whether you need them or not.