*190,27
Located under the liver and to the
left and right of the heart, the
frog's simple lungs are like a couple
of bags with thin walls.
>S(01),0,191
*191,27
The lungs play a key role in the
respiratory system.
>S(01),0,192
*192,27
As the frog inhales, air goes into tiny
sacs in the lungs. In these sacs, oxygen
is transferred to the blood.
>B(01),0,195
>E(01),0,193
*193,27
The frog also has two other ways to
respire.
>E(01),0,194
*194,27
It takes in oxygen through its skin and
through the thin membranes that line its
mouth.
>E(01),0,195
*195,27
Unlike frog lungs, human lungs can
hold a lot of air.
>S(01),0,196
*196,27
Since a frog has three ways to respire,
it doesn't rely on its lungs as much.
>B(00),0,0
>E(01),0,197
*197,27
Humans can expand their rib cages to
help their lungs fill up with the air.
>S(01),0,198
*198,27
Instead, a frog must drop and raise
the floor of its mouth.
>E(01),0,199
*199,27
A frog larva--or tadpole--begins life
with no lungs at all. It has gills
instead.
>S(01),0,200
*200,27
The tadpole develops lungs as it grows
into a frog.
>E(00),0,0
*1000