Acid in your stomach

[BertiWooster]

The acid in your stomach is so concentrated that if you were to place a drop on a piece of wood, it would eat right through it.

So , how does your stomach keep from digesting itself?

[Clanad]

"There are cells in the stomach that secrete mucus and a base, bicarbonate. This mucus coat containing the base is able to neutralize the acid secreted by another group of cells. The stomach contents is acidic, but the acid is neutralized by the mucus if the acid trys to come in contact with the cells of the stomach." (Source: Natural Science News)

[woofgang]

The story of St Martin's stomach
http://www.guineapigz...m/AlexisStMartin.html

[jomifl]

yet strangely enough we cannot digest wood.

[squarebear]

You haven't tried my wife's cooking jomifl ;-)

[theprof]

Oh dear. Time for a definitive answer.

Firstly, the acid in the human stomach is indeed hydrochloric acid and has a pH of around one or two. Even at this concentration, hydrochloric acid will not burn through wood inside or outside the stomach no matter how long the acid is in contact with the wood. If you've read otherwise, you've read a pack of lies.

Secondly, the stomach constantly produces a bicarbonate compound that adheres to the mucus contained on the stomach wall. The bicarbonate neutralises the acid upon contact which means that the mucus plays a minimal role in preventing stomach wall erosion from hydrochloric acid exposure.

It is the combination of the bicarbonate and mucus that prevents the stomach from digesting itself. Some people are unable to produce sufficient bicarbonate to work with the mucus. Such absence of bicarbonate in the stomach mucus is the cause of a high proportion of gastrointestinal ulcers.

[BertiWooster]

Very interesting

What does pH means - and on the scale of potency ( if that is a correct word to
use ) is a pH of one , the lowest ?

On the scale of ' dangerous' acids , where does hydrochloric fits .?

[jomifl]

You could try googling pH, however if you want a quick and superficial explanation(I only do superficial) read on. pH is a measure of the hydrogen ion concentration on a logarithmic(base 10) scale. The scale is centred around 7(neutral) anything below 7 is acid, anything above 7 is alkali. Hydrogen ions (H+)and Hydroxyl ions(OH-) neutralise each other. Excess H+ is acid, excess OH- is alkali. pH1 is 10X more acid than pH2 etc. The strength of an acid depends not only on the amount you have in solution but also on how much the acid molecule forms H+ions(which cause the acidity).Hydrochloric acid is nearly 100% ionic so is a very strong acid, Weaker acids such as acetic form a low percentage of ions so can not give a very low PH even when at a very high concentration.

[johnheritage]

It constantly relines it's self, your body is continually repairing it's self at a rate that, if stopped, would mean you'd die not long after.

It's doing it at a molecular level as well, watching for errors in the transcription of DNA and free radicals escaping for the electron chains in the mitrochondria, and countless other places.

The prime reason for dying is being a live. Eventually the damage from things like metabolism and everyday activity gets too much, and disease appears. Alzheimers is just a build up of neuronal plaques that are cleared out of the way usually, but some isn't, and it collects.

pH drops very rapidly with a few drops of acid in water. But the pH alone isn't enough to say it'll digest a chunk of wood. I could have a solution with a pH of 1 with so little acid actually in it, it would barely do anything.

To reduce wood to carbon, for metabolism, you'd be after a strong dehydrating acid like sulphuric.

Acid's don't always behave in the way you'd expect them to. Hydrofluoric acid will dissolve laboratory glass, but can't escape a plastic cup.

I've used 98%, boiling sulphuric mixed with other things to clean laboratory glassware. It'll turn a big wad of tissue into a bubbling tar in a second or two, with lots of fun hissing and steaming. But then, the acid won't react with other things until it's diluted down a little.

There are also super acids, combinations of two components, that have pH's down to -25. One of the first one's was given the nickname Magic, because it could dissolve a candle; something a normal acid can't do.