HYPOTONIC SOLUTION

[thriller13]

When we go for a swim, the water in the pool is hypotonic to the cells in our body. How come our cells do not absorb the water and burst? any help would be greatly appreciated. thanks

[Fried Zygote Sandwich]

Well, the outer layer of skin cells is usually dead anyway I believe. There is also a substance that is secreted, keratin I think?, that makes our skin waterproof. Overproduction of this makes the skin not stick to itself and causes dandruff.

[Poison]

There is a wax like substance above the outer layer. You can test it by dropping some water on your skin. It stays as a sphere like structure. Plus outer layer does not allow water to pass easily.

[Navin]

Sometimes the water enters and the cells expand causing those wrinkles.
However they do not burst as they are closely packed.

[chicoguardian]

water being hypotonic does not play a big role with cells, water flows in and out a cell in certain was depending on the concentration, it will get rid of the water not burst

[Terry K.]

Yeah, that it why you get pruned, it's actually your cells secreting the jellious material, I also think it's keratin, that is used to withhold some of the water, the keratin acts as a sort of exterior membrane to the skin because of the secretion. Also, the secretion is made of lipids, and lipids are insoluble, so there you go.

[mith]

In plant cells there's the cell wall there to prevent the cells from expanding too much, in our skin cells, they're probably limited in size by fibers such as collagen and elastin.

[MrMistery]

Epitelial tissue has very few fibers, practically non-existent...

[mith]

hmm, our bio teacher showed up skin tissue the other day and said it was dense connective tissue made with collagen. Im inclined to think he's wrong...again :\

[Fried Zygote Sandwich]

Plant cells prefer a hypotonic solution so they stay turgid. Animal cells burst because they don't have a cell wall.


But here's a quote from wikipedia that backs up what I said previously about keratin.

Keratin is a tough, insoluble protein found in the outer layer of the skin of human beings and many other animals. This outer layer of skin is called the epidermis. The outermost layer of cells of the epidermis contains keratin. The keratin in these cells makes the skin tough and almost completely waterproof. In places where the skin is exposed to much rubbing and pressure – such as parts of the hands and feet – the number of cells containing keratin increases and a callus develops. Cells that contain keratin are constantly being shed and replaced by new ones. The condition known as dandruff results when the scalp sheds such cells.

[thriller13]

thanks soo much everyone

[MrMistery]

hmm, our bio teacher showed up skin tissue the other day and said it was dense connective tissue made with collagen. Im inclined to think he's wrong...again :\

Oh boy, structure of the skin. Ok, here it goes:
Skin is composed of 3 layers: epidermus, dermus and hypodermus.
The epidermus is a pluristratified squamos keratinised epithelial tissue formed from 20-25 cell layers. These are divided into 5 regions(also layers): base layer, spine layer, granular layer, lucid layer and the 5th one whch i can not translate. The first 2 make up the germinating blanket and the last 3 make up the rigid blanket. It is estimated that it takes aproximately 3 weeks for a cell to reach the top layer from the base one.
The dermus is made out of dense connective tissue. This is made out of the papillary dermus and the reticulary dermus. In the papillary layer you can find the dermic papiles(duh!) which are more obvious on your hinger and which give you fingerprints. In the reticular dermus you can find many colagen fibers, along with a lot of intercelular substance and few cells.
The hypodermus is made out of connective tissue(we call it "lax" in romanian but i don't know how it's called in english)with a variable number of fat cells that form adipose padicules(around 200-400) around blood vessels and nerve endings. Here you can also find the hair folicules according to some biologists(others place it in the dermus) and the glomerule of the sweat glands.

So you see, Dave, your teacher knows some biology, but something tells me i would do a better job than him