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Author Topic: types of skin  (Read 4778 times)

Offline ukmicky

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types of skin
« on: 28/10/2006 19:53:14 »
Why is it the soft tissue in our mouths can withstand hotter water than the skin on our hands, when the skin on our hands is tougher.

Why can we pour boiling hot coffee in our mouth without pain but not on our hands.


 

Offline neilep

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Re: types of skin
« Reply #1 on: 28/10/2006 20:16:29 »
Hi Michael,

Do I even need to say I'm not the expert here  ?...but surely the fact that the mouth is wet must have something to do with it...
it may have a coling effect !

just a thought...
 

Offline iko

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Re: types of skin
« Reply #2 on: 28/10/2006 20:51:40 »
Best guess,
hot coffee is istantly diluted in saliva and distributed on a wider surface.
Mucosa is actually more exposed to burns.
Does it make sense?
May be we do not need to wikiped this time!
Have fun

ikod
 

another_someone

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Re: types of skin
« Reply #3 on: 28/10/2006 21:02:03 »
It is not about whether the skin can take more or less heat, it is about how many heat sensitive pain sensors exist in an area of our body.

I have heard a story of a man, some centuries ago, fighting a fire in a lighthouse that had a leaden roof, had molten lead drop into his mouth and this he swallowed.  He felt no pain from the hot lead, because there were no heat sensitive nerves in the intestines, but the lead solidified and blocked his intestines, so he died from starvation.
 

Offline neilep

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Re: types of skin
« Reply #4 on: 28/10/2006 21:25:59 »
Well, and thereby goes a happy tale !  ;) ;D
 

another_someone

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Re: types of skin
« Reply #5 on: 28/10/2006 21:45:37 »
And the moral of the story is that if you are fighting a fire in a building with a leaden roof, do not look up and open your mouth at the same time.

BTW, the reason why you have more heat sensors on your hand than in your intestines is because you are far more likely to try putting your hand in the fire than to indulge in unintended fire eating, so your body gives you more protection against the former than the latter.
« Last Edit: 28/10/2006 21:47:58 by another_someone »
 

Offline iko

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Re: types of skin
« Reply #6 on: 28/10/2006 22:02:35 »
Hey hey hey,
before the intestine there should be tongue and palate...
Lots of sensors up there!
Didn't you like the dilution solution of the problem?
Saliva+various fluids make up over 1000mL per day...
The 'lead drinker' story too should follow the old rule:
1 case is just one case
2 cases are a coincidence
3 cases make up a scientific paper
...still far away from proven evidence.

ikod
« Last Edit: 28/10/2006 22:07:06 by iko »
 

Offline ukmicky

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Re: types of skin
« Reply #7 on: 29/10/2006 02:12:47 »
Hi iko, Neil ,George and everyone and thankyou for all your replies.

Firstly a mouth full of hot coffee isn't going to get diluted much by a little bit of Silvia and rather than acting as a barrier wouldn't it act as a transport mechanism transferring the heat of the hot coffee directly to the skin quicker than if there was no Silvia.

Also as the Silvia is produced by two small glands underneath your tongue the top of the tongue and the roof of the mouth ain't going to get much protection.

Secondly the mouth, throat and especially the tongue is full of sensors which are capable of feeling pain.

The skin in the mouth also seems to be hardier even though its softer than normal skin which is weird as hot water which would blister the skin on the back of your hand does nothing to skin anywhere in your mouth.


PS i love this spell check
« Last Edit: 29/10/2006 02:20:36 by ukmicky »
 

another_someone

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Re: types of skin
« Reply #8 on: 29/10/2006 02:37:59 »
Secondly the mouth, throat and especially the tongue is full of sensors which are capable of feeling pain.

Not all pain sensors are the same.

http://www.madsci.org/posts/archives/aug2000/967653140.Ns.r.html
Quote
Somatic (i.e. body) sensory perception can be divided into 4 basic categories:
  • Tactile sensations elicited by mechanical stimulation applied to the body surface (touch etc.).
  • Proprioceptive sensations elicited by mechanical displacements of muscles and joints (i.e. how the body senses its position and the position of its limbs relative to one another).
  • Thermal sensations including separate cold and warm senses.
  • Pain sensation elicited by noxious stimuli.
Each of these modalities uses a particular type of receptor which can encode the features (quality and frequency) of a given set of stimuli. Pain sensation is mediated by "nociceptors" (from the Latin nocere, to injure). These are divided into separate receptors for mechanical pain, heat pain as well as nonspecialized "polymodal" receptors which respond to multiple types of noxious stimuli. To activate a receptor, a stimulus must be of a suitable intensity as well as of a suitable quality. Thus the answer to your question is that the intensity of a stimulus will determine the number of pain receptors which can be activated even though the repsonse by any given neuron will be identical. This is not always the case though as pain receptors are connected to neuronal axons of two particular fibre types- A(delta) and C fibres. A(delta) fibres carry fast pain sensations (abrupt, sharp pains) as their conduction velocity is higher than for C fibres which carry slow pain (the sickening burning sensation which sometimes follows fast pain) signals.

Remember, these receptors and the fibres that they are connected to are in the periphery. The signals that are generated travel up eventually to the central nervous system and are extensively processed along the way- as is the response WHO eventually results in movement or action aimed at ending the pain. What determines the specificity of the initial signal though is the receptor type (or types ) activated by the stimulus. For example, there are 5 different receptor types for tactile sensation as well as multiples types involved in sensation of pain, proprioception and temperature.

The skin in the mouth also seems to be hardier even though its softer than normal skin.Hot water which would blister the skin on the back of your hand does nothing to skin in any part of your mouth.

I think this really is down to saliva (both providing a protective layer, and through evaporation - you could probably do the same by making sure that the back of your hand is covered in cold water before you pour the hot water onto it, and make sure it is continued to be supplied with cold water while the hot water is there).

I don't think that the skin in the mouth is any less likely to blister, although I do think it tends to heel faster when it is damaged.
« Last Edit: 29/10/2006 02:40:52 by another_someone »
 

Offline iko

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Re: types of skin
« Reply #9 on: 29/10/2006 07:32:14 »
Hi iko, Neil ,George and everyone and thankyou for all your replies.

Also as the Silvia is produced by two small glands underneath your tongue the top of the tongue and the roof of the mouth ain't going to get much protection.

...two sublingual glands are small, but parothid glands (just under your ears) are bigger and squeeze saliva through a little tube (duct) directly into your cheeks.
There is enough saliva and mucosa surface to maximize dilution and spreading, cooling off efficiently hot sips.
ikod
 

Offline neilep

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Re: types of skin
« Reply #10 on: 29/10/2006 17:06:18 »
Michael,


Forget about the above responses the real answer is it's because of The Numskulls living
in your head http://en.wikipedia.org/wiki/The_Numskulls









They are there to cool things down when you shovel hot food and drink into your gob !!


Sheesh !!..I really wonder sometimes !!....It's obvious isn't it ?


 

Offline ukmicky

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Re: types of skin
« Reply #11 on: 29/10/2006 17:48:44 »
So its all down to Cruncher , i should have known ::) :)
 

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Re: types of skin
« Reply #11 on: 29/10/2006 17:48:44 »

 

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