When I read your question, I was reminded of an hilarious Tony Hancock episode in the late 50's/60's called "The Blood Donor". (For our American friends, Hancock was a genius of comedy on the radio and television).
Hancock has just given blood, and he and another donatee are discussing A&P. They are discussing why we need blood. Hancock says that we need blood because the heart's gotta have something to pump around, and that it's no good having a heart "banging about all day if it's got nothing to pump around." Then the other donatee asks "Why do we have a heart then?" Hancock says that we have a heart because "otherwise you're blood would sink to the bottom of your boots... and that a heart saves you having to stand around on your head all day and jumping up and down to keep the blood moving about!"
The other donatee then asks, "Are you a doctor then?" and Hancock says, "Nah, I never really bothered."
Obviously the above dialogue does not in anyway justify the pure genius and hilarity of the sketch "live". Even now 40 years later, I find it hilarious. Pure, pure comic genius. Nothing will ever match Hancock IMO. Way ahead of his time. Sadly missed.
Can anyone else remember?
(BTW, no I wasn't alive at the time!)