Holding in a fart can poison you? From your own cite:
As for Michael Levitt. He’s famous in the field as a pioneer for his research. I’ve read many of his papers. That’s why I would prefer a cite of his directly from the medical literature rather than from Salon. (You might want to note, however, that he has moved on from fart research in recent years and most of his major papers are decades old. Perhaps that’s why other doctors no longer agree with him.)
A Google search is not a substitute for understanding a subject.
Ahh yes, when asked for a cite to support YOUR statement, you criticize the cites I provide.
Again, you have made a very bold statement about what happens when you hold in a fart, demanded cites from others, and provided nothing whatsoever to support your claim.
Do you actually care to support your claim, or are we all supposed to take your word as gospel?
Exapno, kindly explain what happens to (held in) gas that is already in the rectum causing a positive pressure in the area. Now explain what happens when more gas from large intestine wants to get into the rectum.
I can easily see how gas from the rectum could migrate ‘upstream’ when the valve is relaxed to allow large intestine gas to try to pass through.
You’re saying this never happens?
I have no idea about the valves, etc. But the idea of some part of the anatomy selecting the non-smelly molecules to emit, and retaining the smelly ones for later? What is that, Sentient Rectum Theory? I cannot imagine any plausible mechanism by which that would happen.
I don’t think I understand what you’re trying to say with this scenario.
Go back and read the excellent post of si_blakely. The entire length of the gut, from the mouth to the anus, can be thought of as a series of connected tubes, each with a one-way valve at its opening. Every stage along the way moves the contents downward with what, for simplicity’s sake, can be considered peristaltic motions. Peristalsis works by a series of transverse muscle movements squeezing the contents, like fingers squeezing a tube of toothpaste. Food moves into the stomach; chyme moves into the small intestine; dessicated waste moves into the colon; dead bacteria, bile, and wastes are converted into feces which moves into storage in the rectum.
Barring pathological conditions, at no point does anything ever move upward or backward in this system. Doing so - against the perpetual one-way movement of peristalsis and against the material that is being moved by it - would not merely be difficult; it would result in severe pain and possible injury. Normally, as I said, intestinal pain is caused by mere gas and water pressure against the sensitive lining. It takes very little pressure to cause intestinal pain.
So, what happens at the end of the process? Here it is, in good clear one syllable words, from about.com:
The rectum can store all the feces for a normal bowel movement. It expands when the pressure is released, which is why a turd can be longer than eight inches. Diarrhea can release additional, not-fully-processed, waste and water from farther up in the colon.
What about the gas? The gas is normally created by the bacteria in the colon and moves in the same direction as everything else. The gas is trapped with the feces and is forced out when the pressure against the sphincter muscles lessens.
Where is the valve you speak of in all this? There is no distinct valve between the sigmoid colon and the rectum. The last valve is five feet farther upstream at the entrance to the large intestine. The gas does not travel there. Nor is there any need. The rectum is capacious enough to store the waste for a normal bowel movement, even if held past the usual warning signals.
Can the gas or feces be forced past the rectum into the sigmoid colon? Well, there is no distinct wall of separation between them. Pathological constipation could overload the rectum. However, under normal conditions the downward pressure of the muscles is far greater than the pressure we can exert on the sphincter muscles. Those can hold the opening but can’t by themselves force the internal material upward. Possibly the complete dessication of waste by prolonged constipation can block the opening and create a backpressure. But pathologies almost by definition can do tremendous damage to any part of our systems. Under normal circumstances, nothing happens except that the gas is slowly and unobtrusively (or quickly and obviously) released. It doesn’t go anywhere, certainly not back through any valves.
What happens when more gas is pushed through the intestine? You expel it. Go ahead, try holding your sphincter muscles completely closed against gas for any length of time. You can’t do it to block any and all gas from escaping. You probably can keep waste from expelling, at least for a certain length of time, but the size of a gas molecule… Well, we’ve already been through that. It’s smaller than you can imagine. It will leak through.
This is why I love the SDMB! If this discussion had been taking place in a bar somewhere, there would be blood on the floor by now. Hooray for the internet - it allows us to disagree about farts without resorting to physical violence.
Lemme see if I get this right, there is no valve between the colon and the rectum. Gas molecules are so small that your sphincter, closed as tightly as you are able, is unable to block gas from escaping. Yet, it is inconceivable that gas can migrate from the rectum to the colon, even though there are no valves or sphincters whatsoever to block its path?
Since when did a belch become a “pathological condition”?
You may stake some opposition to my personal theories about what might cause the phenomenon and that’s fine, assuming you actually argue against my theory and not a misunderstanding of it, and assuming you can back it up with a cite and your own opposing theory.
But you can’t argue against the phenomenon itself. It’s direct personal experience and it’s duplicatable.
I admit that I can’t be certain what the explanation is for what happens, but I know for certain that it does happen.
So long as your claim is limited to, “I can hold in my farts for a while”, I have no beef with that. It’s when you start with the fanciful explanations for what happens to your farts after that which causes me to call bullshit.
Am I the only one thinking that there doesn’t have to be a “natural” valve? Suppose the back pressure of holding it in causes it to squeeze its way back past the next poop in the shoot. That’s what I always imagined that dissipation feeling was.
Look, you’re not quite getting my point. No matter how many times you claim that everything moves in one direction, there’s nothing magical about your intestines that makes that true. It’s all governed by physical law. Let’s review the situation:
There is a pocket of gas at the bottom of your rectum, ready to be released. On one side, the sphincter, which is held deliberately closed tight against the passage of gas. On the other side, you have a seal formed by feces and the walls of the rectum.
There is no valve, no positive separation between the rectum and the colon, only that seal, which is entirely dependent on the structural integrity of shit. There’s no way that a cork make out of poo always provides a stronger seal than a tightly closed sphincter. If the seal is weaker than the sphincter, then the pressure buildup will be released by the gas moving past the seal, into the colon. It’s not some fanciful idea that requires the rupture of your digestive tract, it’s simply the failure of a seal that is made up of structurally questionable materials.
Dude, you’re the one making the claim that we have industrial strength anal sphincters. That mean you’re the one who has to back it up with a cite. That’s the way it works around here.
Hey, why aren’t you asking jackdavinci for a cite of his claims while you’re at it?
I provided cites that claimed flatulence can back up into the colon from the rectum. Now it is your turn to support your side with something other than stating it can’t happen.
You claimed that it never ever happens without intestinal damage, under the presumption that shit can form an airtight seal. I’ll take the flesh/flesh seal of a non magical, consumer grade sphincter over the flesh/shit seal of the rectum any day of the week.
Your claim also implies that a person who is attempting to hold in a fart actually does fart, but can’t tell the difference. Are they are so deluded into thinking they didn’t fart, that they no longer recognize the scent of hydrogen sulfide?
The only two actual claims I’ve made are that farting in a different way changes the way it smells, and that feces and farts can retreat a small distance. These two claims are direct personal experiences that have happened many times. Anything else that I’ve said has been speculation. If there is some other claim you think I’ve made let me know. So far it seems like the only actual facts you’ve brought in to dispute anything has only either been applicable to a misunderstanding of what I was saying, or else to one of my speculations. The only thing I’ve seen you bring to counter my actual claims is condescension and simple denial.
I don’t know the answer. But I cannot help recalling the South Park episode in which people are spontaneously combusting, and Kyle’s dad discovers that it’s the result of fart retention. The breakthrough is when he realizes that all of the victims had just gotten new girlfriends/boyfriends.
