I was seeing this patient Mr. D, a man in his 50's, for hypogonadism, currently treated with testosterone shots weekly.
He has a history of mumps orchitis. Also has a history of partially treated obstructive sleep apnea, bad enough to cause polycythemia.
So, I was explaining to the patient and his wife that this may be primary or secondary hypogonadism (problem in the pituitary, or in the testicle). Had to go into some basic endocrine physiology:
"The pituitary gland which is part of the brain, makes hormones (LH & FSH) which then stimulates the testes to make the male hormone, testosterone. So, when you have low testosterone levels, this can either be a problem in the testicles (primary) or centrally (secondary)...."
At this, the patient's very prim and proper wife of 10 months (second marriage) cracked up. She tried to swallow her giggles to no avail. She guffawed. Mr. D and I looked at her blankly.
I did what I usually do in these situations: I checked to make sure my fly wasn't open (it wasn't). And asked her what was so funny.
And so, the prim and proper Mrs. D, with tears in her eyes, blurted out between laughs:
"I always thought it was the testicles that controlled the brain, and not the other way round!"
One of the funnier situations I've had in a while.