The random-est questions pop into my head and I always wonder what the answer may be. Thank God for Google. My question is weird, and some of you may think you know the answer, but you will be surprised of what the answer actually is.
So, why do our stomachs growl?
What is it that makes our stomachs shout out? Hunger is certainly a factor. When you haven’t chowed down in a two hours, receptors in the walls of your stomach trigger the hunger-arousing hormone ghrelin, which tattles to your brain that the pipe is empty. There are other things, like low blood sugar, that also send that message. And your brain, being the boss, steps in to solve that problem by releasing the hormone orexin, which tells your stomach it might be time to fill ‘er up again.
First the hormone triggers your stomach’s smooth muscles to contract. Acids and other digestive fluids are deployed in the stomach and intestines to get the space ready for the next meal. The contractions move in a ring-shaped formation along your entire gut, forcing remaining mucus, food and bacteria from the area. These contractions produce vibrations, which are responsible for making the racket. The grumblings can last up to 20 minutes and repeat every hour or two until you’ve gotten food in your belly.
But the noises don’t only occur when you need food, although they’re louder in an empty cave; they happen after you’ve eaten, too. The contracting muscles of your stomach and small intestine are also responsible for mixing food with gas and fluid. These contractions move down the intestinal tract toward the exit just a few inches at a time. All this food/gas/liquid squishing also makes your stomach muscles vibrate, which produces a more tempered rattle. Full Article
I found a website with some ways to prevent stomach growling when in crowded, but quiet places.