How does the Sense of Smell Work?

@Emilski - I'm not an animal expert, but your reasoning makes sense. I do know cats have pretty good smell, though. Sometimes if they get the sniffles, they won't eat, because they can't smell the food.

As far as I know, smell is still one of the senses that we don't understand very well, at least as far as knowing how the chemicals react in our bodies to produce the sensation of smell. With touch and sight it's a little easier to understand how the nerve impulses could give the different sensations. It's odd the think that those same impulses have to be generating smell.

One of the few things I remember from taking organic chemistry in college is that esters are responsible for a lot of fruity smells. I don't remember what their exact structure is, but I remember mixing different chemicals to produce esters. Some of the combinations we made smelled like bananas and apples.

I always wondered how smell worked. This was really interesting. I don't know that I ever really made the distinction between human noses and dog noses either. Dogs typically have much longer noses, so it makes since they could have a larger smell reception area. As far as dog smell or any animal smell goes, though, does the length of the nose always predict smell?

I'd say it's probably true for dogs, at least. If you think about a basset hound or dachshund or any other dog bred to hunt or track, they have longer snouts. Pugs and dogs not meant to hunt generally don't have long noses. As far as other animals go, though, what about horses, do they have good smell? Can't a cat smell well, though? They don't have very long noses.

@parsleypea - I would think that remembering smells just depends on the memory associated with it. I have smelled thousands of things in my life, but there are only a few smells that I specifically associate with a certain memory. Of all the ones I can think of, they are all associated with good things, which is unsurprising.

Whenever I smell those few smells, I automatically get a picture of a certain scene in my life. In contrast, if I smell chili powder or something, I recognize what it is, but I don't link it to anything significant, just food.

There are even some great moments in my life that probably had distinct smells, but that I don't remember. It guess our minds or just selective about what it chooses.

@parsleypea - I think the opposite would usually be true as far as smelling food. At least when I smell food, I get the urge to want to eat. I think that is just a basic human instinct. At least for me, it doesn't even have to be real food cooking that makes me hungry sometimes. There have been instances where I have been out in the woods and smelled a flower or something that kind of smelled like a spice, and it reminded me of a food, and I was hungry.

Thinking about it more, though, I think smelling food might have a brief effect. There have been times when I was really, really hungry to the point of feeling sick. Whenever it came time to finally eat, and I knew I was going to be getting food, the smells actually calmed my stomach down. I guess it is because my body new it would be getting food in a couple of minutes.

How long does the memory of a scent remain with the person. Can a scent spur the mind to remember such details/memories that were not retrievable prior to the "re-living" of that particular scent? Does the memory of a scent linger within the person infinitely...does the memory never leave the person?

Can the sense of smell, in a kitchen, where a cook is cooking something delicious, create an appetite and can the sense of that smell create a sense of being full as well? In other words, can the very scent of food that stimulates appetite also give a feeling of satisfaction that would suffice as much as the actual consumption of that food in their presence?