The
group
formed
by
bronchi
,
bronchioles
,
alveoli
and
an
extense
network
of
capillaries
,
constitutes
the
____________________
:
highly
____________________
bodies
whose
appearance
resembles
that
of
a
____________________
.
We
have
____________________
lungs
:
the
____________________
lung
,
which
has
three
parts
called
lobes
and
the
____________________
lung
,
which
only
has
two
lobes
.
Lugs
are
envolved
by
the
____________________
:
a
sheet
composed
of
two
____________________
.
In
between
both
membranes
there
is
a
____________________
that
allows
them
to
____________________
____________________
and
____________________
____________________
.
After
travelling
through
the
respiratory
tract
,
air
filled
with
____________________
reaches
the
____________________
____________________
,
where
____________________
____________________
occurs
.
Pulmonary
alveoli
only
have
a
layer
of
flat
cells
(
endothelium
)
and
are
covered
by
a
____________________
of
____________________
that
facilitate
gas
exchange
between
____________________
and
____________________
.
Oxygen
is
exchanged
beetween
air
and
blood
by
the
process
of
____________________
:
oxygen
travels
from
the
area
where
its
concentration
is
____________________
to
the
are
where
it's
____________________
.
Oxygen
concentration
is
____________________
in
our
alveoli
than
in
our
blood
.
Carbon
dioxide
concentration
is
____________________
in
our
alveoli
than
in
our
blood
.
The
oxygen
found
in
air
goes
into
the
____________________
,
after
passing
through
the
alveolar
____________________
and
the
wall
of
the
____________________
,
to
be
transported
to
the
body's
cells
.
Carbon
dioxide
found
in
the
blood
passes
to
the
____________________
.
The
air
in
the
alveoli
mixes
with
the
carbon
dioxide
and
it
is
released
as
we
____________________
.
Air
in
the
alveoli
needs
to
be
____________________
constantly
for
gas
exchange
to
function
effectively
.
This
process
is
called
____________________
____________________
,
although
it
is
more
commonly
referred
to
as
brething
(
true
respiration
occurs
in
our
cells
)
.
