What is the oldest part of the average human body and how old is it?

Question

Given that our bodies as we have them today are not exactly the same as what we had as children or even last week, and that cells are continuously being created and destroyed, what is the maximum age that a part of our body could be right now?

Or to put it in a different way, what is the oldest part of our body?

I'm guessing that bones dont change much, but maybe they do! Its easy to think of ourselves as unchanging, but since our hair is only as old as our last haircut + how many weeks it took to grow that much, maybe the same is true of our entire body!?!?!

Answer 1

I am an MD. This is a very interesting question. Another way of phrasing it might be, what is the longest time since any of your cells have divided. i.e. which cell in your body has existed the longest without dividing? Actually, every tissue in your body has a certain turnover rate, with your bone marrow being the fastest (several days) to your brain cells and muscle cells, which essentially don't divide at all after about age 19-22. This is why stem cell research is so valuable, since it carries the hope that the non-dividing parts of our bodies, such as brain and muscle and spinal cord, could be regenerated with the aid of stem cells.
As we get older, our cell turnover rate declines, and our tissues become laden with more and more elderly cells. This is pre-programmed into our cells, on purpose, for some reason. (see below). Of course the end result of this is that we die of "old age" which means we are really dying of lack of cell turnover. Some scientists feel that we may be able to disable this mechanism, to allow us to remain forever youthful. Sharks and catfish are like this, never aging even by the tiniest amount. However, the probable reason that we have a cell turnover "brake" built in may well be a compensation against cancer, which is a runaway reproduction of a single cell line that "goes crazy".
Anyway, it is an interesting thought.

Answer 2

Research fetal deveopment about eight weeks into pregnancy. That will let you know what's oldest. Since cells within bone structure and hair and every visible part of you changes and grows, I would think the oldest part would be the one first to start function, so my answer is the heart itself.

Answer 3

It's easy it's got to be your memory!

Answer 4

I'd like to think it's my nervous system, or more specifically my spinal cord. I think it was the first thing to develop when I was a fetus.

And I'd like to say that my spinal cord is 20 years old, going on 21. :)

Answer 5

yeah, its the nervous system, defo. i clearly remember. its about 8months and two weeks older than me