So in my biology classes we’re starting to talk about tissues. As I was reading about the different sorts of skin I stumbled upon this page that summarized every type. Here’s what it says:
OK, from my own limited experience I can understand how mouth/vaginal lining are probably the same. But normal skin? I’ll guess I’ll just come out and say it – why is vaginal/mouth lining pinkish or light red and normal skin is, well, whatever demographic the owner belongs.
The only things I can think of:
Some sort of pigment.
Oxygenated blood vessels very close to the surface.
Normal skin has a stratum corneum, a layer of keratinous tissue that protects it against damage. The internal epithelia that you mention have no such covering. The lips and other marginal areas have very thin skin.
Maybe I shouldn’t say anything before reading my textbook further, but does that mean there are actual differences between mouth/vaginal and normal skin cells or do the former skins simply not form that layer until before/after they die? The skin of the vagina/mouth does slough off, right?
And, AFAIK, the skin doesn’t form that keratinized layer until the cells get closer to the top. Nametag used the term “stratum corneum”, so I’d listen to what he says.
I have to admit I wouldn’t be nearly as interested in this if it didn’t meantion vaginal lining.
So the vaginal/mouth and ‘normal’ skin is identical except for the keratin which makes the skin on most of our body a harder layer. What causes the lack of this in the vagina and mouth?
Well, squamous cells don’t produce secretions, AFAIK. I believe that all of those are done with cuboidal cells. (Shut up about goblet cells in columnar.)
I think a lot of it would have to do with elasticity that’s necessary, and for less friction.
