Circulation




A blonde teacher was giving a lesson on blood circulation...Trying to make
the matter clear, she said, "Now, class, if I stood on my head, the blood,
as you know, would run into it, and I would turn red in the face."  
 
"Yes," the class said.  
 
"Then why is it that while I am standing upright the blood doesn't run into
my feet?"   
 
The answer came from the back of the class, "Cause  your feet ain't empty."