Andy-san, マイケルsan, 子狼san,
kon'nichiwa
This is typical of Japanese language, perhaps.
It's not really the matter of "one hair" or collection of hair. We might not really think of
"difference" between those two.
There are several reasons why we use "kami no ke" over "kami" or just "ke".
1. The word "ke" is too short and difficult to catch.
2. The word "ke" can be hair of any of body parts.
3. The word "kami" has exactly the same sound with words meaning "up" (上), "paper" (紙) and "god" (神).
4. The word "ke" gives (somewhat) dirty image.
etc. etc.
Some people might use "kami" for more "hair style" or entire image and "kami no ke" for more its condition
or characteristics. However, in linguistic view, there's no such definitions.
There are several stories behind "kami no ke", and most of them have something to do with body parts or
old way of writings or meanings.
Hope this helps!
Natsuko (奈津子),
Team JapanesePod101.com