How does skin and hair shed?

[scilearner]

Hello guys,

 

I know they are dead cells, but how come all the dead cells don't fall and only some do. If these cells are attached by cell adhesion molecules how do they fall? Are these adhesion molecules broken or something?

 

Thank you

[Mr Skeptic]

The skin and hair cells are intentionally dead, as they can be hardened by having less water and more keratin/collagen. I imagine that they wear off or are eaten by the microfauna on your body. Certainly a lot more can be removed as a beauty/softening treatment.

[scilearner]

The skin and hair cells are intentionally dead, as they can be hardened by having less water and more keratin/collagen. I imagine that they wear off or are eaten by the microfauna on your body. Certainly a lot more can be removed as a beauty/softening treatment.

 

Thanks for the response Skeptic So skin cells shred primarily not because they are dead, even living cells wear off like bone, is that what you meant by emphasizing dead cells?

[Mr Skeptic]

Well living cells have self-repair. Dead cells do not. Inside the body, if a cell does die it is recycled and (if all goes well) replaced. On skin, we just keep producing more skin cells pushing the previous ones outward, which creates a moving barrier, a flow that carries away anything within it unless it moves faster than the flow. Our mucous works in a similar manner, we produce a constant flow of mucous that keeps almost everything out.

[scilearner]

Well living cells have self-repair. Dead cells do not. Inside the body, if a cell does die it is recycled and (if all goes well) replaced. On skin, we just keep producing more skin cells pushing the previous ones outward, which creates a moving barrier, a flow that carries away anything within it unless it moves faster than the flow. Our mucous works in a similar manner, we produce a constant flow of mucous that keeps almost everything out.

 

So new skin cells push out old cells making them fall, then why does hair grow very long, wouldn't the new cells produced push the old ones and make them fall?

[Mr Skeptic]

Hair cells are tougher, and are arranged in such a way as to be extruded into a long cylinder. (If your skin was made of the same stuff as hair but in one solid block, you'd be armored but have a lot of difficulty moving.) Making hair in this way takes a little more effort than just piling on the cells: http://en.wikipedia.org/wiki/Hair_follicle

 

Also note the complex structure of each hair:

Edited April 7, 2010 by Mr Skeptic

[scilearner]

Hair cells are tougher, and are arranged in such a way as to be extruded into a long cylinder. (If your skin was made of the same stuff as hair but in one solid block, you'd be armored but have a lot of difficulty moving.) Making hair in this way takes a little more effort than just piling on the cells: http://en.wikipedia.org/wiki/Hair_follicle

 

Also note the complex structure of each hair:

 

Thanks skeptic I appreciate your time in answering my questions