18. What are the valves of the
venous system? What is their
function?

Gap-fill exercise

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The valves of venous system are
inside the veins permit
blood to only in the way
(from the to the heart)
forbid it to in the reverse in
favor of . The valves close
the pressure of fluid column above
(, regarding normal flux) higher
than the pressure before them.
are thus fundamental the
returning of to the heart.