I once read that this is why an ulcer can be a really serious medical problem. It’s a bleeding wound even if the blood isn’t spilling on the ground.
Personally, I think of myself as more like a Fiesta.
I would not count the ears or pores, as they do essentially dead-end, as far as open, or normally openable valves go. The ears end at the eardrums, and the pores end in microtubules at the capillary level. Same for tear ducts, and for the urethra, which tapers out at the nephron level in the kidney.
Genitally, males taper off in the spermatogenesis level in the testes and females, surprisingly to some, end in the peritoneal cavity.
I had a patient swallow a Cantor tube, which traverses the body until it exits at the rectum, with the far end of the tube still hanging out the mouth.
Ears don’t matter, topologically, unless you remove the eardrums that separate the middle ear from the Eustachian tube. Same with sweat pores and urinary/reproductive tracts: they’re all dead ends, not pass-throughs.
Sorry if you’ve heard this before but a topologist is a person who can’t tell his/her ass from a hole in the ground but can tell his/her ass from two holes in the ground.
One of my high school physics teachers would say this sometimes, although he didn’t use the word torus. I’m trying to remember why he brought it up. I remember it had something to do with radioactive particles passing through the body, but I don’t remember the specifics.
What about eyes? Can’t you get from the sinus cavities to the eye socket?
Perfect!
There’s a puzzle/problem in topology called Seven Bridges of Königsbergwhich I encoutered in that Mathematics book I mentioned upthread. Until I read about that I was still trying to solve a version of it that I had seen as a pre-teen and which I spent many hours (mostly in church – see How did/do you pass time in church?) trying to make work. Only after I saw in print that it was impossible did I quit trying.
Do any of you remember such a puzzle/problem? It was a pencil-and-paper thing with a rectangle divided horizontally into two parts, with the upper half divided into two parts, and the lower half into three parts. The idea was to cross each line segment in that figure once and only once without lifting the pencil.
I bet I tried 1000 ways over the course of several years!
I don’t get it. Is the rule that the walk can’t end up on an island? I just ordered the book from Amazon btw, thanks! $.29 (yes, cents) plus $3.99 S&H. :rolleyes:
You have to walk across each and every bridge just once, and you can’t cross the rivers any other way.
All I can do is quote from the wiki article:
That pencil-and-paper version I mentioned had the same basic rule: cross each segment once and only once without lifting the pencil. Where you start or finish is up to you, but you won’t be able to make the complete trip! Either you have to skip a segment or you have to cross one a second time.
But that’s easy - unless you have to wind up on the mainland.
Using this pic: http://upload.wikimedia.org/wikipedia/commons/5/5d/Konigsberg_bridges.png
Begin at top left, and . . .
Oh, no, wait, I see my problem.
Bilge.
There’s the nasolacrimal ducts. I’ve seen people on TV (magician types and what not) that can put a bean in one and have it come out their nose. Also various fluids, but the bean is more wow/icky.
Last year my genus increased by one thanks to an extraction of an upper wisdom tooth whose roots went too far up and a crappy oral surgeon. Took about a month for the extra donut hole to close up.
There wouldn’t be any problem if there were occasional cross connections between the alveolar sacs of the lungs would there? Who knows how many holes there could be there.
Do all sinus cavities have just one opening?
A heart is kinda like a coffee cup. Maybe that’s why some people are loved and feel content, while others always seem to have a hole in their heart that can never be filled.
A porous torus?