Harnesting Chemical Power

[Cogman]

I just want to know, How come you dont hear much about converting chemical reactions from cells and such to electrical activity or mechanical activity. I mean, I've lived for 17 years and I have never had period where I ran out of power . Would it be highly ineffective? and could you make it more effective by using organic features, like growing a nerve for the sole perpouse of connecting houses? would the waist of energy be less then our modern technology?

 

[Jeff7]

Welcome to the matrix.
And it's either harvesting or harnessing.
I wonder that organisms are too inefficient - look at us. We eat food, and awhile later, a lot of it comes back out in an unusable form. That's pretty wasteful. Though I guess it could vary with what animal it is - I saw something that an octopus uses like 80-90% of the food it consumes; some very impressive number like that. I just don't know that the power output could be made very significant - or reliable. One virus gets in and the power grid's offline cause it's got the flu.

 

[Matt]

The modern body converts the energy gained by consuming food into a substance known as ATP which contain high energy phoshorus bonds. The process of producing ATP occurs in the mitocondria which are in essence small energy factories located in every cell.

When splicing one or two of these bonds and thus converting ATP into ADP or AMP a lot of energy is produced. This process occurs whenever and wherever energy is needed, for instance muscle activity, creating enzymes and all those other things the body does to keep itself going. This process of creating ATP out of food and then when needed converting it into energy is very efficient.

Deliberately though, the body doesn't create as many ATP as it could for the very reason that we need to keep the bodytemperature of 37C (98,6F). The inherent production of heat is thus not a flaw, instead it's a processs necessary for the body to keep the overall efficiency at it's maximum. (Most enzymes are optimized to work at 37C).
This is why for instance all mammals need a constant supply of energy as opposed to reptiles who don't heat their bodies through internal heat production. (Need to eat or use the prevalent fatty layer)

It is as explanied above for obvious reasons a waste of energy to use living organisms as energyproducers like in the film "Matrix".

One could though lower the amount of heating required if there are many ppl living in the same room since the body heat produced aids in keeping the room warm.




/Matt, MD

 

[dejitaru]

Welcome to the matrix.

That movie was bullshit.

just want to know, How come you dont hear much about converting chemical reactions from cells and such to electrical activity or mechanical activity. I mean, I've lived for 17 years and I have never had period where I ran out of power .

Some people do run out of power (starve to death).
It would be very inefficient, as most of the energy is used.
You could capture the excess solar or thermal energy from the light bulbs in your house, but why bother?

 

[KenGr]

As I recall there has been some research into life forms (microbes) which eat hydrocarbons and emit hdrogen or hydrogen rich compounds, retaining a lot of the carbon. The net result would be a fuel with less CO2 emissions and a bunch of carbon based microbe carcasses.

 

[dakels]

hey Dr. Matt, is heat output actively/reactively controlled on a sub-cellular level? I thought the mitochodrial heat output was pretty much the same no matter what external conditions were. Therefore its bodily processes which control overall heat. If it's 110 degress out then your body reacts by sweating to release heat. If it's 60 degress out your body then starts to shake to create muscular heat and also on a cellular level metabolize more sugars to create more energy/heat?

Also whats the deal with the electrical signals transmitted via the never fibers, then converted to a chemical signal across the dendrites? then back to chemical.

 

[Matt]

Hi, dakels

You are right in terms of that the relative degree of heat produced by the mitocondria is the same at all times. It is the level of body activity and thus the degree of mitocondria activation that determines how much heat that is produced. As correctly mentioned we need to sweat to cool down or shiver to increase the temperature in order to regulate the body temperature.

The only exception is in the so called "brown fat" which is prevalent in infants only. In that perticular fatty tissue the mitocondrial membranes are short-circuited and no ATP is created, only 100% heat. This is a protective mechanism against hypothermia. Unfortunately this tissue is absent in adults. Imagine going into a cold room and just watching the fat melt away. The process of shivering to increase body temp is not at all as effective as this method.

The so called "electric "signal is actually not a real current produced by the nerves. The "signal" produced by nervous cells is actually a brief depolarisation of the chemical potential that exists in all living cells. The chemical potential is due to different concentrations of mainly Na,K, Ca extracellularly vs intracellularly. The depolarisation is the result of an opening of ion channels in the cellmembrane allowing selective amounts above all K and Ca to move through the membrane. The depolarisation triggers different events in the body, for instance release of neurosubstances in the neurons and contraction of muscles in muscular tissue.

I believe that it could be possible in the future to create circuits that respond to these signals and possibly even biocomputers or organic neural networks. The major cons of using neural fibers are the vulnerability of the fibers and the fact that the process of depolarisation and repolarisation of membranes are extremely energy consuming. In comparison: 1/5 of of the blood flow of the heart goes through the brain in order to supply it with adequate amounts of sugar and O2, eventhough it only weighs about 1/50 of the total bodyweight.
With this in mind you quickly realize that you can't transport electricity, only a 1/0 signal.
Compare this to the loss of energy when transporting information using an ordinary copper cable or fiber optic cable which is nominal.

The answer is like Occam's principle. The easisest solution is the viable one.


/Matt

 

[Matt]

Sorry, this is more biology than technical stuff but I think it answers the question.

Damn... I also write long posts... typical for a doctor not to be able to keep it brief. LOL

I hope that this makes it a little bit more clear or like the old expression: "Still confused, but at a higher level"



/Matt

 

[dakels]

heh Thanks Doc. Now I know more and feel dumber.

Anyways I am curious now. You say the nervous system doesn't actually use electrical signals? I am somewhat familiar the NA+K bonds and other chemical attractions that power alot of sub cellular functions but I thought the nerve cell itself carries an electrical signal. The public is always told something to that effect, I guess to dumb it down.

Where are these electrical impulses coming from then? Is it from the nerve cell to the muscle tissue to then make the muscle react? If so it seems possible to me that if you were able to have a computer+sensor system understand the feintest electrical responses, nerve signal commands could then be applied to mechanical motion. Muscle is like a pulling motor anyways. You could apply these tiny motors built into a prothetic that would attach to the stump. Sensors reading information to the stump could then be relayed to control certain motors in the prosthetic. The more refined those sensors get and complex and small the motor system, the more realistic the prosthetic.

Sound right?

Also the opposite basically happens already as far as I am aware. We can hook up electrodes to make muscles react to the commands coming from a computer. It may not be very accurate but it does show the mechanics.

 

[Matt]

Hi again.

The nerve impulse is actually a wave of depolarisation that propagates through the nervous fibers. If you wish to call the propagation of depolarisation an eletrical current I really don't mind but it's a change in chemical potential. (Ions moving across a membrane rather than electrons moving along the length of a conducting material.

When the depolarisation reaches the synapse (nervous ending) various transmittorsubstances with a short half-life are released, connection to receptors on the target cell.
The resulting action is depending of the function of the target cell. For instance, muscle cells react by releasing Ca into the intracellular space causing muscle contraction.
I don't know how far the researchers have come in terms of establishing a durable interface between neuron and a non-organic sensor but it would surely be a revolution for the prosthetic technology.

In terms of the opposite, muscle contraction can be induced by a strong electrical current but it's through a different mechanism than mentioned above.

Phew... that pretty sums up my current knowledge on neurochemistry. (Was a few years since I studied it)

Anyone out there who know more about the next-gen prosthetic limbs?

/Matt

/Matt

 

[Howard]

The body is very efficient in changing chemical energy into another type of chemical energy that it can use - it's just that no food is 100% digestible and the useless portions must be rejected.

 

[dakels]

well of course I figured if you could exactly explain a functioning bridge between neurochemical and mechanical then you probably would be the richest man on Earth.

I was curious about the relationship. Thanks for the info doc. I'm kinda surprised you even remember as much as an MD and not a researcher.

 

[Matt]

Thanks for the compliment. It's always nice to revive old knowledge. Maybe I should be a researcher within the field of neurology. Time to reconsider perhaps... $$$




/Matt

 

[NogginBoink]

Originally posted by: Cogman
I just want to know, How come you dont hear much about converting chemical reactions from cells and such to electrical activity or mechanical activity.

That would be cool. Heck, we could make one and call it a "battery."

That's what a battery does: converts chemical energy to electrical energy.

 

[dakels]

Originally posted by: Matt
Thanks for the compliment. It's always nice to revive old knowledge. Maybe I should be a researcher within the field of neurologi. Time to reconsider perhaps... $$$




/Matt

Well I know a bunch of PHD researchers and they don't make that much money, well all relative of course. The real money makers are those PharmD's working for pharmaceutical companies.