Sorry if I don't know the right medical terms for this stuff, I just try to read as I go along.
I've never seen a good answer for these questions. After a woman gets pregnant or someone gains a lot of weight, they can get extra loose skin in lots of areas, especially the lower abs. What is that skin? Is it "extra" or is it "loose", or is it both?
I guess there's three skin layers, epidermis, dermis and hypdodermis. So pretend that someone gains a lot of fat around their midsection. The epidermis holds the subcutaneous fat, so that has to get bigger. The dermis holds the connective fibers like collagen, so that at least has to get stretched but maybe it doesn't get "bigger" as in more cells. The epidermis has more cells but that's only because the dermis is stretched out, right? Since it's getting replaced all the time if the dermis was smaller then the epidermis would be smaller.
So then pretend that person looses weight. The person gets lean enough where the subcutaneous fat is mostly gone, so the hypodermis must get at least a little smaller. I don't know what's true about keeping the same number of fat cells or gaining new ones. So, what is the loose skin? Is it, like, lots of extra hypodermis cells stretching out the dermis? Is it, the same number of dermis cells with broken down collagen, like the same amount of skin cells just with less elasticity? Is it both more cells and less elasticity?
Skin can look vascular. There's almost nothing between muscles underneath, the dermis has good elasticity, and the hypodermis is small with very little subcutaneous fat. So skin looses vascularity when it hangs because it's not elastic, has too much skin if that's possible, or has a big cushion of subcutaneous fat.
When mothers get the lower abdominal pouch, it was probably because the connective fibers got torn up, right? IT's not necessarily the case that they got a lot more subcutaneous fat, maybe some (Ok, maybe a lot sometimes), so the hypodermis only got stretched because it was being pushed up against. Maybe there's more cells there but it has to attach to the dermis, which is really the thing that's stretching. The dermis had to stretch and the connective matrix got torn up, and the epidermis gets bigger because everything underneath gets bigger. Then she gets loose skin after birth, but is that extra tissue, stretched out tissue, or both? Which layers are responsibile for the problem?
There's two kinds of loose skin I've seen, the kind with fat still attached and the paper thin kind. That's where a lot of internet arguments start about loose skin, because subcutaneous fat is really part of the skin so it can still be fat and loose. The only difference between the two I think is that the subcutaneous fat is gone in one case, really the fat cells are just empty. So the paper thin case is easier to talk about because you're really just wondering why the dermis either has too many cells or has the same cells as before and isn't elastic.
So what is true and what is myth about loose skin?
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