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AJI

Original Poster:

2,675 posts

104 months

[news] 
Tuesday 2nd October 2012 quote quote all
The 'simple' act of being able to smell something.
Sounds straight forward but having watched a TV program aprarently it is not.

To set off the process a molecule of a certain substance would have to travel up the nose and reach the smell receptors that are linked to your brain.
These smell receptors 'grab' the molecule and 'investigate' it.

As the brain works on the motion of electrons in order signals can be sent and received it is assumed that electrons will do the 'investigation' of the molecule.
But how does a single (or multiple) electron(s) 'investigate' a molecule in order to then send some 'information' about it to the brain?

The TV program showed the electron 'passing through' the molecule in a simple animation, but this just left the question as to what has changed to that electron in order it now posesses information about the molecule?


Any more insight from the knowledgable?

annodomini2

5,109 posts

138 months

[news] 
Tuesday 2nd October 2012 quote quote all
http://www.bbc.co.uk/news/science-environment-1282...

Basically they're still not quite certain.

GokTweed

3,724 posts

38 months

[news] 
Tuesday 2nd October 2012 quote quote all
That sounds weird. I would have thought that the nose only posesses receptors for certain molecule types and when these are fired the brain then processes the information to find out the composition of the smell. Humans are crap at this because our smelling area of the brain is st. Dogs are miles better.

Simpo Two

60,413 posts

152 months

[news] 
Tuesday 2nd October 2012 quote quote all
GokTweed said:
Humans are crap at this because our smelling area of the brain is st. Dogs are miles better.
I'll take 'opposable thumbs' over 'good sense of smell' smile

GokTweed

3,724 posts

38 months

[news] 
Tuesday 2nd October 2012 quote quote all
Simpo Two said:
GokTweed said:
Humans are crap at this because our smelling area of the brain is st. Dogs are miles better.
I'll take 'opposable thumbs' over 'good sense of smell' smile
Bet your wife's pleased wink
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Shaolin

2,683 posts

76 months

[news] 
Tuesday 2nd October 2012 quote quote all
As far as I'm aware it's about molecular receptors.

Molecule sniffed up conk binds/fits to a particular receptor protein which fires off an action potential if it's the right shape. A range of receptors send their messages to the brain which analyses them all and comes up with a decision such as "bacon" or "fart".

Having an enhanced smell bit of the brain results in being able to cross reference associated smells and probably compare them to past smells. As our sense of smell is so poor we probably can't imagine what it is like for dogs who have a much greater experience and sensitivity any more than we can imagine a fish lateral line sense.

GokTweed

3,724 posts

38 months

[news] 
Tuesday 2nd October 2012 quote quote all
Shaolin said:
As far as I'm aware it's about molecular receptors.

Molecule sniffed up conk binds/fits to a particular receptor protein which fires off an action potential if it's the right shape. A range of receptors send their messages to the brain which analyses them all and comes up with a decision such as "bacon" or "fart".

Having an enhanced smell bit of the brain results in being able to cross reference associated smells and probably compare them to past smells. As our sense of smell is so poor we probably can't imagine what it is like for dogs who have a much greater experience and sensitivity any more than we can imagine a fish lateral line sense.
The lateral line in fish detects water pressure changes, our fingertips are quite good at this but i see your angle.

Shaolin

2,683 posts

76 months

[news] 
Tuesday 2nd October 2012 quote quote all
The brain wiring is probably quite different though, so I imagine the perception is totally different.

Our skin touch, pressure and pain receptors are all pretty much identical but where they connect to in the brain determines whether we percieve pleasure or pain depending on the depth in the skin of the receptor.

Simpo Two

60,413 posts

152 months

[news] 
Tuesday 2nd October 2012 quote quote all
Ah, Pacinian corpuscles eh?



Not a lot of people know that...

GokTweed

3,724 posts

38 months

[news] 
Tuesday 2nd October 2012 quote quote all
Shaolin said:
The brain wiring is probably quite different though, so I imagine the perception is totally different.

Our skin touch, pressure and pain receptors are all pretty much identical but where they connect to in the brain determines whether we percieve pleasure or pain depending on the depth in the skin of the receptor.
Actually they are quite different in some respects. Some have large fields of sensation some have small. Some are dedicated pressure sensors some are just free nerve endings. The free nerve endings tend to be pain wheras nerves like pascinian corpuscles are dedicated pressure sensors and have a relatively complex structure.

Shaolin

2,683 posts

76 months

[news] 
Tuesday 2nd October 2012 quote quote all
The basic wiring is the same though.

Bet

GokTweed

3,724 posts

38 months

[news] 
Tuesday 2nd October 2012 quote quote all
Shaolin said:
The basic wiring is the same though.

Bet
Well yeah they are all nerve fibres, some myelinated some not. There are different pathways they take to get to the brain and obviously different parts they eventually terminate in.

AJI

Original Poster:

2,675 posts

104 months

[news] 
Wednesday 3rd October 2012 quote quote all
Shaolin said:
As far as I'm aware it's about molecular receptors.

Molecule sniffed up conk binds/fits to a particular receptor protein which fires off an action potential if it's the right shape. A range of receptors send their messages to the brain which analyses them all and comes up with a decision such as "bacon" or "fart".

Having an enhanced smell bit of the brain results in being able to cross reference associated smells and probably compare them to past smells. As our sense of smell is so poor we probably can't imagine what it is like for dogs who have a much greater experience and sensitivity any more than we can imagine a fish lateral line sense.
Sounds very plausible.
The TV program that I saw however showed it on an electron level whereby the receptors within the nose sent electrons 'through' the scent molecules in order they could be 'interrogated'. Maybe this is what you mean when you say "action potential"?

The message from the TV program being that it relied on the uncertainty principal (schrodinger's cat and all that) in order the electron can be both sides of the scent molecule in order that the correct signal could be sent back to the brain.

How this method works over any another method was not highlighted within the program but as the Science topics of late have been discussing such details I thought this may 'fit in'.



FarmyardPants

2,564 posts

105 months

[news] 
Wednesday 3rd October 2012 quote quote all
Shaolin said:
As far as I'm aware it's about molecular receptors.

Molecule sniffed up conk binds/fits to a particular receptor protein which fires off an action potential if it's the right shape. A range of receptors send their messages to the brain which analyses them all and comes up with a decision such as "bacon" or "fart".
Yes I think this is how it works. It's the particular combination/ratio of firing receptors that are recognised as a particular smell. I draw this conclusion from the fact that two chemicals with very similar molecular structures can smell very different from one another, plus of course lots of familiar smells are made up from a cocktail of molecules. As we experience new smells in early development we add them to our database, in the same way that we learn to recognise things with our other senses. Some chemicals are odourless (to humans) which would indicate no receptors that fit. Presumably we have evolved these receptors to avoid danger or otherwise help us survive, which might explain why some things are odourless (air, water,..) while things like burning trees, bad food etc stink smile. Other chemicals can impair our sense of smell temporarily - presumably until we can shed/renew the receptors (achoo!) that have been bound up by those molecules. The sense of smell is the first to degrade as we age, perhaps because it needs a good rate of cell regeneration to keep it working effectively (which is neatly explained by the bound-molecule-to-receptor hypothesis).

Funk

15,387 posts

96 months

[news] 
Wednesday 3rd October 2012 quote quote all
Shaolin said:
A range of receptors send their messages to the brain which analyses them all and comes up with a decision such as "bacon" or "fart".
I can't explain why, but this sentence made me laugh out loud..hehe
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