8. Do fish present an open
or closed circulatory system?
How many chambers does a
fish heart have? How does
blood flow throughout the fish
body?

Gap-fill exercise

Fill in all the gaps, then press "Check" to check your answers. Use the "Hint" button to get a free letter if an answer is giving you trouble. You can also click on the "[?]" button to get a clue. Note that you will lose points if you ask for hints or clues!
As in every vertebrate circulatory
system of fish closed, i.e., blood
flows within blood vessels.

The heart has only two
chambers: a thin-walled atrium a
muscular ventricle. The
(oxygenated) blood comes from gills
and gains arteries tissues, then
venous blood collected by veins and
the atrium of the passing
to the ventricle pumps the venous
blood the gills to be
oxygenated.