My dog has no nose. How does he smell?

The morning after a delightful evening at which my wine-writer friend supplied the drink and my affineur friend the cheese, I opened the fridge to get butter for toast. Even though the fridge door was only open for perhaps thirty seconds, this was long enough for an invisible fume of dank, drain-like smell to escape, hover a minute or so in the kitchen, then wind its poisonous way through the flat to the bedroom, where it woke up the Man quicker than I’ve ever seen him come to consciousness on Sunday morning before!
The cheese, wrapped though it was in several layers of waxed paper, was not asleep.
What is the relationship between smell and taste? The theory is that we have tastebuds for just five flavours: salt, sweet, bitter, sour and umami. All the other delicate arrangements of flavour that we experience while eating are actually through the olfactory bulb in the nose.
If this is the case, why do we experience the smell of so many food stuffs as so different from their flavour?
As a child, coffee seemed repellent to me to taste, but I used to go out of my way coming home from school in order to sniff the air next to the coffee stall on the market. Durian fruit is notoriously bad-smelling, but pleasant to eat. And cheese can smell like a teenage boy’s gym kit but be absolutely delicious.
I think (and this is based on nothing more than personal observation and wild speculation) that there must be some change in how we perceive things that are inside our mouths. The smell may be the same, so the olfactory experience is technically the same, but it is now combined with a mouthfeel (cool, salty, fattiness in the case of cheese) and our expectations of the sensation is altered.
By this latter, I don’t just mean that we expect the époisses to taste good, but that it fills our sensory horizons so we no longer have a standard of non-smell to compare it with. When I worked in the cheesemongers, many customers (not all under 8) would wrinkle up their noses on entering the shop and perform amusing mimes of themselves vomiting at the smell. If they didn’t immediately flee in fits of laughter, we were always able to cure their nausea. A taste of cheese, ideally Montgomery’s Cheddar, would instantly dispell the tyranny of the air heavy with the aroma of dozens of cheeses.