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 The
Hair follicule
The
hair follicle develops and grows in cycles called anagen, telogen
and catagen defined by growth, rest and transition from growth
to rest, respectively.
The
quantitative relationship of anagen to telogen depends on an
individual cat's age, breed, body site, inherited factors, hormonal
factors and environmental factors.
The
longer hairs coming from those follicles with longer periods
of anagen. One of the most potent anagen stimulators is the
presence of sunlight (seasons with the greatest daily periods
of direct overhead sunlight correspond very closely to the maximum
growth activity of the feline hair follicle).
A
normally coated feline typically has a few types of coat hair:
The
Guard hairs are the longer and stronger of
the feline hair types, and they are typically the source of
each breed's coat color and pattern. The major differences between
the primary and secondary Guard hairs are the primary Guard
hair's greater overall growth rate and thicker shaft diameter
and the secondary Guard hair's greater overall numbers. The
categorical separation of these hair types can be visually defined
in breeds (Cornish Rex has secondary Guard hairs but not primary
ones). Their differences can be microscopically defined by looking
at their arrangement which consists of a centrally located primary
Guard hair being flanked radially by several Awn hairs in a
pattern reminiscent of a flower petal.
The
Down hairs are the shorter coat hairs which are characterized
by their soft texture and powerful insulating capability.
The
lanugo hair is present in utero and at birth
but is shed shortly thereafter, for 10 to 14 days after birth
as well as the expression of the coat specific for the kitten's
breed. After this hair is shed, the transtional stage begins
and is characterized by a growth of secondary hair emerging
at six to ten weeks and persisting to six months.
All
those sort of hair types could be see in the Siberian.
Differences
in hair appearance are heavily influenced by differences in
the genes coding for proteins necessary for the formation and
stability of hair strands and/or these genes' regulator sites
which control the speed and frequency in which hair develope
process occurs.
Feline
hair production involves much more than a single gene deciding
whether hair is present or absent. Thus, any consideration of
the growth (or lack thereof) of this system would be incomplete
without considering these many factors and, perhaps, others
which were not even think.
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