Deep Question my little HL2.net geniuses...

[Sulkdodds]

Wow, this was such a deep question.

Wait, no, it was a question with an easy factual solution, not a deep question at all. Kudos to otherguy for giving a deep answer.

 

[Saturos]

Wow, this was such a deep question.

Wait, no, it was a question with an easy factual solution, not a deep question at all. Kudos to otherguy for giving a deep answer.

:arms:

 

[VirusType2]

:borg arms:

 

[jverne]

Life is an intricate balance between the forces of growth and repair, and decay. The body can easily repair any and all damage and decay it encounters. The body's repair system is so good that, barring any disasters or serious illnesses, a human being could survive for many hundreds of years. "Wear and tear" is not the cause of aging. Environmental factors can influence aging, to be sure, but they are not its cause. The human body's repair mechanisms are too good for that.

However, the human body's repair mechanisms are almost too good for survival. Unfortunately, the same mechanisms that allow our cells to robustly repair damage and replace parts is the same mechanism by which cancer operates.

Individual cells really don't care what happens in the body. They are just along for the ride. They take in resources, they output what their genetic code tells them to output, and they reproduce when the enzymes in their environment and inside the cell wall match up with the DNA code for reproduction. However, if the DNA code for replication is too lenient--allowing the cell to reproduce at just about any time--then the cell will continue to multiply until all the resources in its environment are used up by its children. The body's mechanism for repair is to alter the amount replication hormones in the blood-stream, carefully controlling which areas experience the most rapid growth, and which ones' growths have been slowed.

However, the failure of this system is that the cells, and the cells alone, are responsible for their own reproduction. They don't have to vote with the rest of the cells in the body to get the right to reproduce, they simply reproduce when they are told to do so by their genetic code. When a mutation happens in the reproduction mechanism of the cell, there is the possibility that a cell will simply start reproducing like crazy. It will form a cancerous tumor which invades other tissues, continually expanding with near-immortal cells that reproduce continually. This eventually kills the entire body.

Thus, to avoid cancer, the body has evolved a system that ensures runaway cancerous cells stop reproducing--and die. Part of this system is the reduction of telomeres-- strands of "buffer" DNA that wear down with each replication. When the buffer dies down after too many replications--like the wick of a burning candle, the cell's offspring are rendered infertile, and die of excessive mutation. In this way, cancerous tumors can quickly die off, and most go unnoticed, as they rarely reach dangerous sizes.

Unfortunately, this system has also introduced aging to the human body. After a certain number of years, most of the body's cells have already reproduced as much as they can. Their offspring are infertile mutants with poor reproductive systems and poor production. Repair slows. Decay creeps in. Soon, the body can no longer keep up with the damage, and disease, and finally death sets in.

Since humans had usually reproduced before aging began to set in, or may have died long beforehand, aging was never selected against in evolution. There was little significant benefit to living over 40 those many thousands of years ago, when few people lived past 20.

Thus, now that medicine and easy living keeps us alive long past 40, we see the effects of age on our bodies, and many people suffer great hardships.

Maybe someday, geneticists will discover a way to circumvent aging while also avoiding cancer, and promote treatments to slow or stop the aging process. There is no reason why humans can't remain as twenty-year-olds for hundreds of years--as long as cancer and runaway mutation is kept in check.

you can officially have my babies! i love you

 

[jverne]

Oxygen isn't toxic, It's just extremely flammable. I saw a thing on The Science Channel about the air and what makes it up, and scientists, to prove that the air isn't pure oxygen, placed a mouse in an environment with only pure oxygen. The mouse lived much much longer then the other mice, but was extremely flammable.

oxygen is not flammable. oxygen is oxidizing.
methane is flammable and uses oxygen to reduce itself.

 

[VirusType2]

oxygen is not flammable. oxygen is oxidizing.
methane is flammable and uses oxygen to reduce itself.

Fire is fueled by oxygen though.

 

[Eejit]

oxygen is not flammable.

That's like saying water doesn't become wet.

 

[jverne]

That's like saying water doesn't become wet.

well yeah...sort of.

but you can't just throw oxygen into a combustion engine and except it to compress and ignite.

 

[Saturos]

That's like saying water doesn't become wet.

jverne is right.

If you've ever picked up a welding/brazing torch before and tried holding a flame to an open oxygen valve, nothing will happen. You need acetylene.

 

[VirusType2]

Let's clarify. Without oxygen you cannot have fire.

In a car engine, it burns gasoline and oxygen. Without both, the spark from the spark plug will not ignite anything.

 

[jverne]

Let's clarify. Without oxygen you cannot have fire.

In a car engine, it burns gasoline and oxygen. Without both, the spark from the spark plug will not ignite anything.

oh yes you can...why do bullets "explode" then?



hint: nitrogen

 

[theotherguy]

Interesting.

So things I described as wear and tear that come with aging, like worn out joints, eyes that no longer lubricate themselves properly causing blindness are an effect of telomeres?

Well, its not like you have a little bit of lubrication in the beginning of your life and it wears down like machine oil. In the joints , specialized cells produce collagen, cartilidge and other materials. It stands to reason that if these materials are produced constantly, "wear and tear" would be quickly repaired. However, whenever it is repaired after a major trauma, cartilidge sets like bone. You have to wear a cast when breaking a leg to avoid abnormal bone growth--the same goes for joints. Over time, small amounts of damage are repaired in the joints, but it is rarely noticed, and can set incorrectly, leaving open patches of bone that aren't lubricated. Some forms of arthritis are caused by autoimmune diseases and infection. Other forms of arthritis are indeed caused by inefficient production of cartilidge as cells age and can no longer reproduce. Wrinkling is largely caused by the inability of cells to produce collagen.

However there are some things in the body wear or don't repair themselves like the brain and teeth, for example.

That's very true. Treatments that end aging in these organs will require more drastic changes to the genome or perhaps stem cell therapy. Another interesting genetic engineering treatment that we may have in the future is the ability to regenerate nervous tissues and even entire limbs (both of these are holdovers from our amphibian past, but are disabled by other genes involved in fast scarring.)

So many things old people have problems with later in life, like heart, kidney failure, liver failure, and brittle bones are an effect of telomeres, else they would repair themselves.

Sometimes.

 

[VirusType2]

Another interesting genetic engineering treatment that we may have in the future is the ability to regenerate nervous tissues and even entire limbs (both of these are holdovers from our amphibian past, but are disabled by other genes involved in fast scarring.)
.

Yeah, I remember hearing about this, didn't they use a pig?

 

[Krynn72]

theotherguy is dominating. I never knew about telomeres, or how we age and its fascinating.

 

[VirusType2]

oh yes you can...why do bullets "explode" then?



hint: nitrogen

because nitrogen is an oxidizer.

 

[Raziaar]

theotherguy is dominating. I never knew about telomeres, or how we age and its fascinating.

I briefly covered telomeres in this college biology book I was reading... but **** me if I would ever remember it or most of the other shit going on there, or remembered it long enough to even recall it beyond the pages it was on.

God damn there's too much info!

Apparently it's not even one of the terms I bothered adding into my poorly maintained notes of terms that I had going before I took my GED test. Can't even quote that here, it's much too long.

 

[Slug Advisor]

What makes us age?

Jews.

Spoiler

Kudos to theotherguy for knowing stuff.