How does our nose sense different smells?

Answer 1

Hey there...

Up on the roof of the nasal cavity (the space behind your nose) is the olfactory epithelium that has to do with smelling. The olfactory epithelium contains special receptors that are sensitive to odor molecules that travel through the air.

These receptors are very small and there are hundreds of different odor receptors, each with the ability to sense certain odor molecules. An odor can stimulate several different kinds of receptors. The brain interprets the combination of receptors to recognize any one of about 10,000 different smells

Answer 2

The nose allows you to make scents of what's going on in the world around you. Just as your eyes give you information by seeing and your ears help you out by hearing, the nose lets you figure out what's happening by smelling. It does this with help from many parts hidden deep inside your nasal cavity and head.

Up on the roof of the nasal cavity (the space behind your nose) is the olfactory epithelium. Olfactory is a fancy word that has to do with smelling. The olfactory epithelium contains special receptors that are sensitive to odor molecules that travel through the air.

These receptors are very small - there are at least 10 million of them in your nose! There are hundreds of different odor receptors, each with the ability to sense certain odor molecules. Research has shown that an odor can stimulate several different kinds of receptors. The brain interprets the combination of receptors to recognize any one of about 10,000 different smells.

When the smell receptors are stimulated, signals travel along the olfactory nerve to the olfactory bulb. The olfactory bulb is underneath the front of your brain just above the nasal cavity. Signals are sent from the olfactory bulb to other parts of the brain to be interpreted as a smell you may recognize, like apple pie fresh from the oven. Yum!

Identifying smells is your brain's way of telling you about your environment. Have you ever smelled your toast burning? In an instant, your brain interpreted the smell and a problem and you knew to check on your toast.

You learned to associate a certain smell with burning and now your brain remembers that smell so you recognize it. Your sense of smell also can help you keep safe. For example, it can warn you not to eat something that smells rotten or help you detect smoke before you see a fire.

Answer 3

Our nose contains chemoreceptors which are activated by certain chemicals in the air. These chemoreceptors, when activated give off an action potential (electrical current in a way, which travels to the olfactory part of the brain), this part of the brain is specific for interpreting action potentials as the smells of the chemicals which correspond to each receptor.

Basically the signals going to the brain are ALL the same, but where they go to is different.

Answer 4

Every time we inhale, currents of air swirl up through the nostrils, over the bony turbinates, to a “sheet” about the size of a small postage stamp that contains millions of olfactory receptor neurons. This is the olfactory epithelium.

Each of the millions of olfactory neurons has minuscule filaments (cilia) extending from its knob. This knob is located at the tip of the olfactory neuron and the cilia project from the knob directly into the atmosphere. This is the only part of the brain that projects into the atmosphere. The cilia contain olfactory receptors, specialized proteins that bind low molecular weight molecules (odorants). One of the big breakthroughs of the past 15 years was the discovery by L. Buck and R. Axel of a large multi-gene family that encode for these olfactory receptors. Each receptor has a pocket (binding site) that is just the right shape to bind either a specific molecule or a group of structurally similar molecules. The interaction of the right molecule with the right receptor causes the receptor to change its shape (structural conformation). This conformational change gives rise to an electrical signal that goes first to the olfactory bulb and then to the areas of the brain that convert the electrical signal to a smell.

In 1996, Peter Mombaerts found that olfactory neurons containing the same olfactory receptor, while randomly scattered within one of four spatial zones of the olfactory epithelium, project to only two specific areas (glomeruli) in the olfactory bulb. These findings suggest that the bulb transfers information that is broadly distributed in the olfactory epithelium into a highly organized information map that is in essence a map of the information provided by the different olfactory receptors. Systematic studies have shown that different odorants are represented by distinct spatial activity patterns in the glomerular layer of the olfactory bulb. These results in turn suggest a combinatorial mechanism for olfactory coding wherein the responses of olfactory receptors to odorants produce spatial patterns of olfactory bulb activity that are characteristic for a given odorant or blend of odorants, e.g. a perfume. Thus, it appears that these spatial patterns of activity create the information that leads to recognition of odor quality and intensity and discrimination between odors. This information is processed at higher levels of the olfactory system and in the brain giving rise to the perception of smell.

Answer 5

olfactory nerves in our noses

Answer 6

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