Waves are heard crashing on a beach.
The video starts with a man floating
in the water in an inner tube.
His upper torso and arms
are exposed to the sun.
The skin uses sunlight
to help manufacture vitamin D,
which is important
for normal bone formation.
But there’s a downside.
The sun's ultraviolet light
can cause major damage to the skin.
The man's head is shown
in the upper right of the screen.
A cross section of skin
showing the individual
cells is enlarged on the left.
Some dark cells
containing melanin are shown.
The sun is shown shining
on the cross section of skin.
The outer layer of the skin
has cells that contain the pigment melanin.
Melanin protects skin
from the sun's ultraviolet rays.
These can burn the skin
and reduce its elasticity,
leading to premature aging.
Dark spots of melanin
spread up through the cells,
turning all the cells darker.
When the melanin gets
to the top it disappears and
the skin returns to its normal color.
People tan because sunlight causes the skin
to produce more melanin and darken.
The tan fades
when new cells move to the surface
and the tanned cells are sloughed off.
Some sunlight can be good as long as
you have proper protection from overexposure.
But too much ultraviolet,
or UV, exposure can cause sunburn.
The skin layer reddens
as it burns and the surface
of the skin shrinks and sags
The UV rays penetrate outer skin layers
and hit the deeper layers of the skin,
where they can damage or kill skin cells.
People,
especially those who don’t have much melanin
and who sunburn easily,
should protect themselves.
Fewer melanin containing
cells appear in the skin
You can protect yourself
by covering sensitive areas,
wearing sunblock,
limiting total exposure time,
and avoiding the sun between 10 am and 2 pm.
A layer of sunblock
covers the surface of the skin.
A clock also appears
showing the hours of 10 am and 2 pm
The skin layer return
to the first undamaged view
Frequent exposure to ultraviolet rays
over many years
is the chief cause of skin cancer.
And skin cancer
should not be taken lightly.
The surface of the skin becomes darker
and the cells become more uneven.
Large dark spots appear
in the center of some cells.
Check your skin regularly
for suspicious growths or other skin changes.
Early detection and treatment are key
in the successful treatment of skin cancer.
The video ends with the opening image
of the man in the water.