Are we really all no more than 2 years old?

I just had an epithawhatsit. That person 3 years ago who’s memories I have. That wasn’t me! None of the atoms in my current self were in that person.

Or were they? Is the brain the exception to the no older than 2 (or whatever the figure is) years of the body’s cells?

I’m trying to find a coherent question somewhere in here.

I don’t think there are any reliable studies on how often all your atoms turn over. I’d bet you still have a lot of original issue ones though.

And many cells last for your lifetime.

I beleive that once you’re an adult brain cells no longer regenerate. However, current research shows that that may not be true in certain areas in the brain.

Epidural? Epiphyseal fracture? episcleritis? Episiotomy? Epispadias? Epistaxis? Epithalamus? Epithelial cyst?

I’m going with epiphany.



We just had a simuldoohickey.

While the turnover of many compounds in your body is quite rapid, it’s statistical. Even with the most rapidly turned over elements and compounds (like Water and oxygen) you still have many atoms from three years ago.

With slowly turned over atoms, like the calcium in your bones, you probably have most of the atoms you had many years ago (once you reach adult size). Calcium turnover in bones is primarily done by “remodelling” at the surface, so a small number of the atoms are exchanged often, but most remain locked in: you’ll still have them when you die. your bones also have most of your body’s phosphate (-P04) and a sizeable fraction of your carbonate (-CO3) thou phosphate and carbonate in your cells and blood often turnover rapidly, and by urine excretion, replaced via your diet (phosphate) and respiration (carbonate)

That may sound like a quirk that shouldn’t count, but your bones are a large fraction of your chemical dry weight. Most of your other tissues are mostly water. Of course, osteoporosis and other conditions can change the amount of bone minerals you retain over the decades

Try looking at is as symbolic: despite all the activity of life, your basic framewiork remains for years, down to the atomic level.

Excellent reply. Thankyou. :slight_smile:

People don’t change, their atoms do.

Does anybody have any idea how this question applies specifically to brain and other nervous cells?? I know it’s been said that brain cells do not regenerate - ie, they do not divide themselves and multiply to make up for other cells that might have died.

But brain cells, like all other cells in the body, are constantly changing, taking in water and other chemicals, expelling others. How much of the content of my brain cells has changed over a two year period? :wink:

LOL. And I don’t mean that in the much overused sense, I mean, LOL.

It wasn’t so much the line itself, it was the timing.

Except that it wasn’t one. Brainstorm maybe, but not epiphany.

(Sorry, couldn’t resist.)

**Epiphany: ** (3).1 a sudden manifestation or perception of the essential nature or meaning of something
.2 an intuitive grasp of reality through something usually simple and striking

(Definitions taken from mirriam-webster online.)

I would think that his brainstorm could have led to an epiphany, in either of those senses. :slight_smile:

Only some of us, & then only in maturity.

‘I’ am a function, not an object.

Men, maybe. Us ladies have cells in our ovaries that will only go away one or two at a time, month by month.

Even so, those cells being alive, they will be exchanging fluids, salts etc with the rest of your body. They aren’t in stasis.

Good luck finding an answer to that one. I spent the better part of an afternoon trying to find the answer to a simple question like how long it takes blood to completely replenish in the answers were all over the place.

I think I might be able to help a little, though. Water comes and goes, that’s for sure, and the glucose your cells “eat” is combined with oxygen and expelled, so that stuff is always churning. Things like proteins are incorporated into the cells themselves, so barring damage or cell death, I don’t know if ANY of those atoms are ever swapped out, or if they are, only rarely. After all, you bump an atom out of a protein, you have a brand new compound that probably acts ina completely different way.

And finally, there’s the DNA. IANA geneticists, but it seems to be that that would HAVE to stay stable as long as a cell is alive. Knocking around atoms there leads to cell death or cancer. So stuff like water and carbon may have totally swapped out the last couple of years, but the DNA in your long-lived cells is the same.