noises in the stomach in hunger is due to to movement of gas.muscles of food pipe show peristaltic motion.in stomach and small intestine, the muscles r involuntary muscles,i.e they can not be controlled according to will.so whether food is present or not, it is always working n trying to move the food in one way direction to large intestine.in the absense of food, intestine n stomach is filled with gas which makes funny noises when they come across the continous contraction n relaxation of smooth muscles of intestine.in stomach hydrochloric acid is produced by parietal cells which in absense of food, beginn to irritate the mucosa cells of stomach.this type of erosion causes necrosis and which,if persists for long, causes ulcer.

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