How does the human body differentiate between abrasions and cuts or stretch marks? And if the body sees them similarly, why do they heal differently?


How does the human body differentiate between abrasions and cuts or stretch marks? And if the body sees them similarly, why do they heal differently?

In: Biology

Not sure what you mean? It depends on the depth/extent of the injury. If the damage reaches to the basement membrane separating the skin from the underlying tissue, the skin can’t repair itself properly so it “paves it over” with a bunch of collagen fibers, forming a scar.

A stretch mark is essentially the skin tearing itself from the underlying tissue growing too quickly.

I think what you are asking is more about how they heal, and what concerns you have for each. Stretch marks are of no concern, think of it more as scarring from quickly growing skin.

An abrasion, which could also be called a cut in some cases, generally has a “slice” look. A flap, if you will. You want to get into the wound and clean it out to avoid festering bacteria causing infection. Then, in some cases, stitch it back to hold it closed and aid in the healing.

A puncture is a little trickier. It usually plunges bacteria much deeper, and creates a sort of suction on the way out, closing the wound. Often you’ll want to make sure to bandage and use antibacterial ointment on these for several days.

Tetanus is also a factor for any dirty wound.

So it is less about how your body “views” the injury, and more about what to watch for in wound care.

an organ reacts to stress that is acted upon it

the degree of damage is what dictates the pathway of healing, the two pathways of healing are “regeneration” and “repair”

when stem cells of the organ die, and thus normal organ cells cannot be regenerated, that is when the body decides to heal with the “repair” pathway, utilizing fibroblasts, myofibroblasts, and capillaries, it lays down granulation tissue, which ultimately forms a scar.

easy example to understand these concepts, you can have a small cut to your skin, where you dont even remember being cut, but it leaves a mark, and it dissappears over a couple days as your body regenerates new cells (keratinocytes)

or you can have a cut that is just a bit deeper, which reaches the basal cell layer of the epidermis; the basal cell layer of the epidermis contains the stem cells of your skin, when these stem cells are damaged, the regenerative capacity is now gone, so the only way by which the skin can heal itself, is through scar formation.

The injuries you listed are healed by the same process, your body doesn’t differentiate. If you get cut or scratch or abrasions or a complete amputation your blood clots up and starts the healing process. Stretch marks occur when there is intense and fast expansion of skin, the middle layer of your skin tears showing deeper layers and tissue, so u see the stretch marks. The broken parts will eventually re connect similar to how a cut re connects over time. But will still leave a scar

Cutting is cutting, abrasions are abrasions and stretchmark are from stretching.

Every one of them is caused by something else. A cut is the skin being damaged by something sharp sliding on the skin and causing damage. Abrasions are from rubbing against something (for exampld the skin of your hands on the sidewalk when you fall). It’s caused by friction. And stretch marks are from stretching the skin relatively slowly (gaining weight, growing up. Stretching fast enough so the skin can’t keep up with regenerating, but slow enough so the skin doesn’t break. Well, imagine the scenes from all the movies where there is some kind of alien/monster growing inside a human really fast. The skin becames thinnier (like a stretchmark) but at some point the alien grows too fast (or tries to escape the body – stretches his arms and legs so he takes more space) so the skin has to stretch really really fast and breaks.

Human skin is pretty elastic so it doesn’t break that easily and we are able to have stretchmarks.

Human body “sees” these damages differently. Cutting parts pieces of skin, abrasions are like layers of skin being rubbed of, and stretchmarks are healing fast enough so you don’t really notice getting them and healing. Mostly.