____________________
ossification
begins
with
____________________
____________________
.
Begins
at
4
weeks
but
ossification
begins
at
8
weeks
.
This
process
continues
until
around
____________________
____________________
old
.
Most
of
the
skeletal
system
is
formed
this
way
.
The
steps
are
that
____________________
formation
at
site
of
future
bone
.
These
cells
differentiate
into
____________________
.
Formation
of
____________________
____________________
with
shape
of
future
bone
.
Cells
on
surface
differentiate
and
lay
down
____________________
.
Perichondrium
at
moveable
joints
will
be
called
____________________
____________________
.
If
there
is
no
moveable
joint
,
perichondrium
will
differentiate
into
____________________
.
Perichondrium
turns
into
periosteum
.
Osteoblasts
lay
down
compact
bone
called
bone
collar
.
____________________
in
center
of
model
____________________
,
the
matrix
becomes
mineralized
and
the
cells
dies
leaving
large
hollow
lacunae
.
This
is
called
____________________
____________________
.
Blood
vessels
grow
from
periosteum
and
grow
into
lacunae
.
Osteoblast
brought
into
lacunae
from
periosteum
.
They
lay
down
bone
trabeculae
.
They
also
change
calcified
cartilage
into
____________________
bone
.
This
is
called
the
primary
ossification
center
and
it
forms
in
the
diaphysis
.
Secondary
ossification
centers
form
in
the
epiphysis
.
Osteoclasts
and
blasts
remodel
bone
to
form
____________________
cavity
.
Ossification
continues
up
to
the
____________________
____________________
.
