How Does This Happen?

[questor]

Perhaps some of you biologists or biochemists can answer these questions.

let's say that you get a deep cut on your arm and have a few sutures, the wound will heal and all you will see as evidence of the cut is a scar. how do

the cells know how to fill on only (approximately ) to the proper level rather than growing out to a large bulge, or not growing at all? if you remove a tooth, the socket will fill with blood, the cells will organize, and the wound will heal over to the approximate level of the rest of the adjacent bone. how does it know when to stop? since the human being is made of atoms, most of them hydrogen and oxygen with some nitrogen, how does the body keep inside the atoms that should be inside and keep out the same elemental atoms

that are outside? why is there not an admixture of these atoms? of course the skin is a barrier to transfer, but when the barrier is lost, burns, cuts, or other means there is still no transfer of atoms.

[cwes99_03]

Part of that huge list of questions is biological in explanation but actually chemical in practice.

All of the allowance of molecules/elements into the body is controlled through chemical gateways. Of course how a body knows how to make these gateways is contained in the DNA. As for fixing of skin cuts and tooth sockets, some of it I would imagine to be abrasive. If you keep running a cloth over a cut in the wood that is being filled with epoxy then the epoxy will only fill the hole to such and such a height before the rag takes any excess away. Similarly gravity and abrassives cause any blood to pool but not build a bubble over a cut.

Now as the cut heals the scab will build up as the skin heals underneath, creating a raised area. It is my understanding that the skin layers themselves do not heal at the top, but layers underneath heal and the top layer that was cut eventually sloughs away without ever actually having repaired itself. Again how or why that happens would be genetic design.

[questor]

Cwess, thanks for the participation. i know it is chemical and biological and controlled by DNA. the question is how, through what dna coding? how can dna measure the exact height a tooth socket must heal to? what prevents your oxygen and hydrogen atoms from mixing with those in the air around you.

when you are swimming, why doesn't your body H2O combine with that of the water around you? do your atoms know that they should stay inside you?

why don't they merge with the atoms around you?

[cwes99_03]

Well if you know it is chemical then you know that your skin is a membrane. There is some evidence that water can and should exchange with water found in the layers of your skin through your hair folicles and pores.

In fact you know how your skin gets wrinkly, it's because it is absorbing water around it (that and the oils that are preventing this from happening are slowly being washed away.)

 

Otherwise you are probably looking for some super deep answer that simply can't be provided on a forum like this and I recommend taking a genetic biology class or a couple of them at the master's level.

[hallenrm]

I think it has to do something with communication between the cells:)

 

When cells neighboring a wounded get to know that some of their neighbors are missing, they get to work. They asseble all the resources necessary to repair the damage. Like all repairs after calamities, they do leave some signs of change!:eek_big:

[IDMclean]

If I remember my biology correctly, the cells release a chemical message that also acts like a toxic spill (analogy) at the same time, and the body responds by cleaning it up and replacing the cells, as the spill is soaked up and the ccells become replaced the bodies response also slows until there is nothing left and the wound is healed...

 

That maybe non-sense though, as I don't have the absolute most reliable memory.

[ronthepon]

Maybe I can give some light here.

 

The reason that some atoms stay in and the rest stay out is beacuse of the condition the atoms etc are.

 

Mort carbon, hydrogen, oxygen, nitrogen etc in our bodies is present in very complicated molecules.

 

In the case of elemental or randomly molecular presence of these atoms, they may or may not be able to enter our body. There are a few pathways that molecules can take such as dissolving in water(of the cells) or getting into some tissues.

 

Then, our body decides (this deciding is programmed into our DNA) wether we need or don't need these molecules.

 

If we don't need, either our defensive systems begin to destro these molecules, or they go out through our excertory system.

 

As for some basic molecules, like water as you said, they are usually absorbed and passed out as urine. Now if water gets on your wounds, there are chences that it won't be absorbed, because the cell memberanes disallow that and no blood vessels are present there. (Very very rare case)

[ronthepon]

I thought that I should post the answer I have to the other question here for clarity.

 

The reason that wound don't overgrow is perhaps because of various restraining factors (like blood clot for example) and the limited divisions allowed for our dedifferentiated body cells.

 

I have seen an example where a kid had utterly burnt his fingers and the inexperienced doc. just bandaged all his fingers together without separating them. Months later when the bandage was removed, three of the fingers had fused together by the skin.

 

Further, just for your GK, when wounds heal to form large bulges as you described, we call it tumors...

[questor]

i understand the mechanism of healing and i understand the fact that the body is a closed system which only allows absorption of specified substances. the thing that i am fascinated by is the information mechanism that prescribes the precision of healing to certain levels,given optimal conditions, and the information that prevents our bodily atoms from communicating with similar atoms outside our bodies. when the spark of life leaves our bodies, all this immediately changes, decay occurs and our bodies readily return to an un-assembled pile of inert atoms.

[ronthepon]

Even I am fascinated by the utter complexity of all the systems of the body.

 

Consider the systems separation of body from environment: defence mechanism.

 

Actually, even I would be interested in knowing just what processes make a dead body instantaneously different from a live one. I guess I'll just have to ask loud one day.

[niin]

how do

the cells know how to fill on only (approximately ) to the proper level rather than growing out to a large bulge, or not growing at all

The outmost cells of your body is specialized in layers.

Each cell in one layer is in contact with many other cells in that layer.

When nabouring cells goes away, it activate the cells and they grow in direction of the missing cells, untill they meet other cells.

Regenration happens sideways. So the layering of the layers stay the same.

Oh...and they can't (normally) grow into air. They need the hole filled with blood first.