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Sunlight and Sun Damage for Skin
SUNLIGHT - A glaring danger
Skin colour depends on a natural brownish pigment called
melanin. Melanin is produced by cells called melanocytes,
situated at intervals between cells in the dermis. All skins rom Scandanavian pale to Ethiopian mahogany, contain the
same quota of melanocytes, but the melanocyte cells of some
skins are more efficient producers of melanin than others.
The function of melanin is to act as a natural sunscreen
that absorbs and filters ultraviolet rays so they cannot reach
and damage the dermis. Sunlight stimulates the melanocytes to produce melanin to stave off UV radiation. Consequently,
people who originate from nearest the equator have the most
efficient melanocytes, while those of Northern European origin have the most inefficient, and are therefore at greatest risk
from sun damage. Freckles indicate unevenly distributed
melanin and poor protection against ultraviolet damage.
Is IT WORTH Getting a tan?
Whereas moderate sunlight enables the skin to synthesize vitamin D, excessive sun is the single greatest threat to skin
health. Dermatologists estimate that 80 per cent of lines,
wrinkles, sagging and coarsening are directly caused by ultra-
violet light. Countless comparisons between the weatherbeaten
faces of octogenarians and their smoother, seldom exposed
body zones show how a lifetime under the sun leaves its mark.
Sunlight ages the skin and creates a potential cancer risk.
it used to be thought that only the "burning" ultraviolet-B rays
posed a threat. Now it is known that whereas 95 per cent of
these short-wave rays are absorbed by the epidermis, 80 per
cent of so-called "tanning' ultraviolet-A rays penetrate down
to the dermis. Here, they undermine the skin's structure by
distorting DNA and RNA at the cell's nucleus and distorting
collagen and elastin arrangements. This damage is both
cumulative and largely irreversible. Distorted cells reproduce
inefficient mutations, resulting in an increase in the number
of lines and wrinkles, a decrease in firmness and elasticity and an epidermis that no longer retains moisture as it should.
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