I was curious as to what we don't know, or arn't too sure of, about the human body. Its because i've been wondering about the feasability of making organs. I know that the brain is too complex to recreate in a lab at this point but i don't see why its not possible to "build" body parts from synthetic or non-human growable materials. For instance- a simple lung could be made by wrapping a long length of nanotubing around a cylinder and then placed in a closed bell jar attached to a pump. The only problem that i can see with that is the blood- but if the nanotubes and cylinder were to be placed inside a humans thorax/chest the nanotubes could surely be attached to the persons blood vessels. I can't see why practically any organ can't be produced non-biologically (with the exception of any organ that relies on nerve endings to opperate such as the organ that processes smell).

So after all that stuff in the middle- what don't we know about human organs, or what are the problems with artificial organs?

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edit- typo

[This message has been edited by Chunkmiester (edited 01-14-2003).]

I don't know how far we've come at the present with artificial organs, but I know that in the past year a scientist had created an artificial that grew out of the back of a mouse.

If these synthetic materials were attached to the body then boy would you know about it. The body would see it as an invading colony of bacteria and try to destroy it. (Causing severe swelling) You would have to somehow work the patients DNA into the material.

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I don't know how far we've come at the present with artificial organs, but I know that in the past year a scientist had created an artificial that grew out of the back of a mouse.

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http://www.kidzworld.com/img/upload/article/a1087i0_bsc.jpg

Not necicarly, there are many materials that the body won't try to reject. Several plastics are often used, as is titanium.

Actualy there are experiments in progress to grow organs without a body. By using geneticaly engineered sourse material they can be exempt from rejection.

Some of the current experiments invlove a biodegradible sponge matrix where different cellular types are encuraged to grow on seperate surfaces. Thus you can get the intricate construction of a grown organ in a much faster time frame. Unfortunatly the complexity of the sponge matrix hasn't been developed far yet.

ummmmm i think nanotechnology will solve it. i mean in a few hundred year we can have tiny lil robots inside us to build new organs and fix up scabs abd cuts

Thanks for the responses. The thing about rejection and the body trying to fight it seems pretty valid- seeing as at this point the only substances that we can make (the equivilent of) one cell thick tubes are carbon and silicon.
As to the points about growing human parts- i don't really mean that sort of thing, i'm talking about building organs from non-organic or possibly plant "parts" as growing human parts is seen as unethical to some people.

Another thought that i had was about converting your body to run on substances other than oxygen and glucose. As far as i understand it the energy from glucose basically comes from its bonds. By breaking down the compound you release the energy in the bonds to be used elsewhere. Also- as far as i know- glucose is simply hydrogen and carbon. When the oxygen comes in contact with the glucose it breaks apart the carbon to form CO2 and then it breaks away the hydrogen to form water. The water is used elsewhere and the CO2 is taken away to the lungs. Therefore- wouldn't it be possible to perform a different displacement reaction, a more efficant one, in order to get more energy from less oxygen or other gas?

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Energy is derived from sugars for cells. Think about it and you will notice that each level of biochemical energy transfer gets more basic as the structures get smaller.

As an individual you eat carbohydrates, protiens, and fats for energy. These are broken down in the digestive system to sugars.

The sugars disolve in the bloodstream and travel to individual cells. Cells can't use sugar as-is so the mitochondrea combine it with oxygen for the energy to produce ATP, a form of chemical energy cells can use.

It is estimated that the body produces and destroys 17 pounds of ATP in a single day.

So no, an alternative energy sourse wouldn't be feasable even considering advanced technologys. The only way that could work would be to put the brain in a robotic body, with equipment to synthesize and suply a truncated circulatory system with sugars and biochemicals needed by the brain.

Thanks Prometheus- my knowledge in biology is quite limited so i thought that the process of converting glucose into energy was far simpler than that. Yet another thought that i had was would it be possible to add extra organs to your body? So for instance a swimmer could have an extra lung implanted so that he wouldn't have to take so many breaths or a sprinter could have a second heart so that the blood would get round the muscles quicker. I know that space inside the body might be an issue but still, if you can transplant organs- why can't you simply add them?

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Actualy in the instances mentioned it would be easier and more effective to play with things on the biochemical level.

For a swimmer there are blood compounds found in crocodiles that make it so that bodies can use oxygen more effectivly and tolerate a higher carbon dioxide level in the body.

With a runner extra blood flow wouldn't be as effective as you would think. The muscle cells can only absorb so much oxygen so fast. When muscles require more energy than can be suplied from the normal oxygen-sugar reaction they use another reaction. I forget the specifics, but the byproduct is lactic acid. A more effecint reaction would lessen muscle fatuge.

Your body breaks down carbohydrates into sugars,the proteins stay as proteins and the fats are kept as is or hydrolysed.

Just an FYI.

Actualy, proteins do not stay as proteins. They are either metabolized for energy (4 Calories/g) or they are broken down for the amino acids. While the human body can produce most of the amino acids it needs from other foodstufs, there are a few that it can not produce (notably Lysine). Usualy these amino acids come from metabolizing protiens. Vegitariens can't get their essential amino acids that way so it has to come from other sourses. Thus the popularity of soy, a plant with uniquily high quanitys of certian amino acids.

Fats can be stored without being metabolized as said. They are usualy metabolized (9 Calories/g) though.