Why do we sometimes get long-term scars for minor wounds or even scratches? Like I still have a scar on my knee from a minor scratch on a fence 8+ years ago? Or a very visible scar was left behind from a shallow dog scratch from a year ago? I just always think of scars as something that comes from more major wounds or is that a made up thing?
In: Biology
Damage is damage. Big or small. If you zoom in on glass using a microscope and hit it lightly with a spoon, you can see micro cracks start to form.
It’s because when we heal from cuts, we don’t replace the area with the same type of tissue.
An open wound is a potential source of blood loss and a site for infection to enter the body, so we’ve evolved to get it closed and healed asap. Obviously first clotting occurs, but then something more permanent is needed. The area between the two surfaces gets filled in with a type of fibrous tissue to bind the edges together. This is simpler and therefore quicker for the body to make than somehow creating new differentiated cells of different types to close the various layers of the skin. That’s why with larger scars you won’t have much feeling within that area compared to the surrounding skin.
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You have different layers of skin. If the cut is shallow enough, the upper layers kind of inject cells similar to stem cells, to make new skin. If the cut goes deeper than the lowest layer of skin, the the body injects a different material, a little more like caulk, and it hardens as a scar.
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