FAO Radiation

[Ex-RoNiN]

You said this:

i read that about every 7 years as we grow and our cells get replace we are physically a completely different person,

...in the thread about the little boy.


Do you have any scientific links on this

 

[aardvark]

You said this:



...in the thread about the little boy.


Do you have any scientific links on this

its true but i think its less - maybe 4 years ( i can't remember) - but yes, all cells get replaced, even brain cells, bone cells, everything.

 

[yak.h'cir]

I've heard this as well, only it was every 11 years.

 

[aardvark]

certainly, human cells can only divide about 50 times before they die.

that means the theoretical maximum lifespan could be 550 years (for the 11 years turnaround) or 200 years (for the 4 years turnaround).

of course its doubtful you could ever approach this in practice.

 

[CF93]

Doesn't skin completely replace itself every 60 days or something like that?

 

[MaxPower]

Doesn't skin completely replace itself every 60 days or something like that?

Mine does it daily, I have eczema.

 

[CF93]

Mine does it daily, I have eczema.

Have a little bit myself, nothing really bad these days, though it used to be worse. You have my sympathies, cause I know how bad it can be!

 

[D.P.]

Its important to not that neurons don't replace themselves, they are more or less fixed from birth. Hence babies are born with massive heads because their brains are fully developed and will not change. Only the skull lengthens changing the face from rounded to elongated. Learning is done by adjusting connections nad connections strengths between existing neurons.

When a neuron dies, thats it. Hence why if your spinal cord is severed it wotn grow back.

 

[D.P.]

Doesn't skin completely replace itself every 60 days or something like that?

I beleive thats correct, the dead skin makes a large proportion of dust in an everage house...

 

[aardvark]

Its important to not that neurons don't replace themselves, they are more or less fixed from birth. Hence babies are born with massive heads because their brains are fully developed and will not change. Only the skull lengthens changing the face from rounded to elongated. Learning is done by adjusting connections nad connections strengths between existing neurons.

When a neuron dies, thats it. Hence why if your spinal cord is severed it wotn grow back.

i believe that current research shows that even neurons replace themselves many times over during a lifespan - how the information is retained (or even stored) is a bit of a mystery at the moment.
its different when the cells are actually destroyed, as in a spinal cord severance.

 

[Radiation]

You said this:

Quote:
i read that about every 7 years as we grow and our cells get replace we are physically a completely different person,

...in the thread about the little boy.

Do you have any scientific links on this

I read it many years ago and also heard it again on some documentary but i can't remember what or where now, i did some searching and could only really find this, there were related bits on other sites but they lacked detail.

http://www.newton.dep.anl.gov/askasci/mole00/mole00482.htm

 

[p4radox]

Surely eggs in ovaries don't get replaced? I thought they were present from birth...

Unless you punch them obviously

 

[iCraig]

Surely eggs in ovaries don't get replaced? I thought they were present from birth...

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Eggs get replaced yes, it's called a period.

 

[Anim]

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Eggs get replaced yes, it's called a period.

you might want to go back to yr8 sex.ed.

Eggs in the ovaries may be one of those few items of the body that dont get replaced but thats me only remembering something i heard a long way back. So probably entirely unnacurate

 

[aardvark]

you might want to go back to yr8 sex.ed.

Eggs in the ovaries may be one of those few items of the body that dont get replaced but thats me only remembering something i heard a long way back. So probably entirely unnacurate

yeah eggs don't get replaced - i forgot about that - but they do have about 300,000 of them - plenty to go around.

 

[iCraig]

you might want to go back to yr8 sex.ed.

Eggs in the ovaries may be one of those few items of the body that dont get replaced but thats me only remembering something i heard a long way back. So probably entirely unnacurate

Well if you think it could be so inaccurate, why are you so sure that it's me who should retake sex ed?

The eggs are replaced in the definition that the same egg isn't recycled per menstrual cycle. It's shed away and another from the ovary replaces it.

 

[Anim]

people werent talking about the position in the body of cells, which is what the menstrual cycle is about. The question was whether the eggs in the ovaries were replaced or not, absolutely nothing to do with a period.