[Jacob-list] horney noses

[Pbs123 at aol.com]

Whenever an area of the integument (skin) is regularly subjected to abrasion 
or trauma it undergoes "sclerification"; that is, some of the tissue hardens 
in response as a protective measure. Our own skin produces callouses which is 
a type of sclerification. Callouses are made of epidermal cells that are 
"cornified." The cornification process pushes skin cells outward after 
depriving them of cytoplasm and cell nuclei etc.
This is the same process by which horn material is produced, but horn 
cornification results in "hard" keratin while our callouses are composed of 
"soft" keratin.
The area including the face and forehead in sheep has the ability to produce 
horn material when induced to do so. Likewise the area around the antlers or 
deer can be experimentally induced to produce additional antler material. The 
specialized cells that generate horns and antlers extend beyond the immediate 
vicinity of the frontal appendages.   

Peter S






-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.pairlist.net/pipermail/jacob-list/attachments/20010925/fd8f7566/attachment.htm