Can someone help me understand how cells "remember"?

I understand the concept of the blueprint that is “me” being stored at a cellular level. I get the concept that most of the cells in my body are being replaced and that there is enough continuity in the replacement process to ensure that I still remain essentially “me”.

Clearly though, the blueprint is modified to some extent during that replacement process. While aging is the most visible sign of that modification, it can also be demonstrated through the scars I have from various injuries throughout my lifetime. Somehow, at a cellular level, those injuries are “remembered” and my blueprint is modified to express them in the physical legacy of scars.

What I don’t quite get is why sometimes the blueprint gets modified as a result of damage, and sometimes it doesn’t (not all injuries scar, for instance).

Can anyone suggest some sites which explain this process in relatively simple terms?

I’m not a biologist or a doctor, but I’m under the impression that scarring has absolutely nothing to do with your DNA. Nothing internally gets damaged for a scar to occur. It’s just that when your body tries to restore itself, there’s damage that the building parts of your body can’t repair. It does the best it can with the uneven edges, but the damage was too great for the healing to completely restore the blueprint, so scarring occurs. This abnormality in the physical structure of the skin is what causes it to stay. However, after hundreds of regenerations, sometimes the abnormality is eventually healed, which is why most scars fade over time.

Jman

You’re pretty much right there, Jman.

When you get an injury, damaged cells release proteins that cause blood to clot (so that you don’t just carry on bleeding). Fibrinogen molecules in your blood start to bind together to form fibrin - as the name suggests, this is a protein that occurs as long fibres, which create a kind of meshwork that helps form a good solid blood clot. Over the next few days, white blood cells, fibroblasts etc begin to remove the clot and lay down fibres of collagen - a very strong fibrous protein.
At first the collagen is laid down fairly haphazardly, and this scar tissue is much weaker than normal skin and looks different.
Over more time, the scar tissue itself is gradually removed and replaced with a more organised structure of collagen fibres. This process is repeated again and again, so tht your scars will gradually shrink and the scar tissue itself will become much stronger.

This process is all controlled by the normal operation of your immune system, endothelial cells (lining of blood vessels)and cells in the dermis of your skin (mainly fibroblasts). There aren’t any changes in the actual DNA of any cells - the scar tissue looks different than your normal skin because it isn’t made up of the normal mix of epithelial cells and proteins - it’s mainly collagen.

What external injury does not cause a scar? If your skin (epithelial cells) is cut or damaged, it will heal with scar tissue. The blueprint does get modified, sometimes resulting from damage: e.g., melanomas from excess sun. If your body receives such an insult, the DNA can be modified or damaged.

Mistakes are made all the time in the ongoing mitosis process. The body, however, has mechanisms for snipping out the mistakes. Sometimes a mistake will slip through the highly sophisticated damage control mechanism.

Yep. Keep in mind that injury healing is a completely different process from the original growth. You’re not really regrowing the original tissue - it’s more like slapping a patch on a tear. Instructions for both methods are in the DNA and are expressed when appropriate.