Humans are said to be able to distinguish 10000 different odors.

I really enjoy this question. The simple answer is no there is not a different receptor for each smell. All association and differentiation happens inside the brain. From my understanding the olfactory nerve just detects that there is a smell and sends the info to your brain. Which then goes to an association area, which pulls in all previous experience and memories of smell to let your brain know what you are actually smelling. When you smell a new smell your brain tries to find the thing closest to it.

For example: I woke up one morning during Christmas and my mom had made beef stew for lunch and pancakes for breakfast. However, to my nose it smelled like cookies. My brain had never experienced those combination of smells before so my brain found the closest thing which happened to be cookies. To someone else it might have smelled completely different. I'm sure many of you have experience things phenomena.

So to answer the question (based on my understanding) there is really only 1 smell receptor via the olfactory nerve. The distinguishing of smells occurs in the association area of the brain, which needs memories, experience, and other sensory info to make a decision (such as taste).