Building blocks
About 100 trillion.^103
Fat cells are
bubble shaped.
They store fat
under your skin.Many blood cells
are red. They
carry oxygen
around the body.Nerve cells are
thin and wiry.
They carry
electrical signals.Bone cells make
your bones hard.
They live in tiny
holes in bones.Cells make tissue
Your body contains
hundreds of different
types of cells that do
different jobs. Cells of
the same type usually
group together to form
tissue. Fat, muscle,
bone, and nerves are
types of tissue. Blood
is a liquid tissue.How big are cells?
Cells are too small to see with the
naked eye, but scientists can
photograph them through
powerful microscopes.
The cells on your skin
are about a hundredth
of a millimetre wide.
The cells on
the surface of
your skin are tough
and flat. They overlap to
form a layer of armour that
protects the softer cells below.A microscope can
zoom in to see the
tiny, flaky cells on the
ridges of your fingerprint.Mo
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