Blood Lesson

[Rondy]

A teacher was giving a lesson on the circulation of the blood. Trying to make the matter clearer, 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 in the ordinary position the blood doesn't run into my feet?"
A little fellow shouted,
"Because your feet are not as empty as your head."

[Spicerack]

Lol.

[waterboatman]

Love it! :o}

[Spicerack]

How old were the kids? I don't know the answer.

[waterboatman]

Blood vessels have one way valves.