Download How fingerprints are formed and why they are unique

How fingerprints are formed
and why they are unique
No match
If two faces can be
exactly similar, why can’t
two fingerprints be
exactly the same?
Our fingerprints start developing at 10 weeks
when the fetus is between 1-3 ½ inches in size
Fingerprints are fully developed
around 4 monthes of age
Skin has 3 layers – the outside, or epidermis.
The inside or dermis. And underneath the skin
is the fatty tissue, called the subcutaneous
tissue.
Skin also
contains hairs,
nerves, and
blood vessels
epidermis
Basal layer
Dermis
When your
fingers are
forming, there
is a basal layer
between the
dermis and
epidermis
epidermis
Basal layer
Dermis
The basal layer grows
faster, so it strains
against the other
layers for space.
This pressure causes
the skin to buckle,
forming folds of the
epidermis into the
dermis
These folds are
random
These folds show up as
ridges on the outer skin
These ridges are also formed on the palms
of hands, soles of feet, and lips!
But this is not
the entire
story. The skin
of a fetus is so
soft and
delicate that
even the
slightest touch
will also create
a pattern in the
ridges
No match
So even identical
twins will not have
identical
fingerprints!
The FBI has nearly 50 million fingerprint records in
its computer database and has yet to find an
identical image belonging to two different people
Since fingerprints are actually deep
underneath the epidermis, they don’t
change much as you age. The
friction ridges will become less visible
because aging skin gets thinner
There are rare genetic conditions where people
are born without fingerprints. These people
typically also lack sweat glands in their skin.
•Adermatoglyphia
•Dermatopathia
pigmentosa reticularis
They cannot pick up
a cardboard box or a
glass! It just slips
right off of their
fingers!
The ridges in our
fingers, palms, and
toes help us to grip
slippery objects.
New skin cells constantly being made
As you can see from
this image, our skin
consists of a layer of
dead cells on the top.
New cells are
constantly being made
deep in the dermis.
They are constantly
pushed up into the
epidermis, and finally
slough off as dead cells
on the top of our skin
Use these directions to create your foldable
1. Turn paper sideways
2. Fold it in half twice
3. Fold the edges to the
middle
4. Cut on solid lines
Turn in for a grade!
Epider
mis
Friction
Ridges
Dermis
Basal
Layer
Hypod
ermis
Dermis
Left Side
- show the Epidermis,
Dermis, and Hypodermis.
Include the blood vessels,
sweat glands, and nerves
in your drawing
Right Side
- Show the dermis, basal
layer, papillae, friction
ridges, and sweat pores
Outside
1. Age when ridges first appear and age
when fingerprints fully formed.
2. What process makes the ridges, and
what parts of our bodies contain these
ridges
3. If the ridge pattern itself is inherited,
why is it different fro each person, even
twins
4. why don't fingerprints change when
you age?
5. People with adermatoglyphia have
trouble doing what simple thing?
6. New skin cells are formed in the ___,
and move ____. the outermost surface
of your skin is composed of ____ cells.