system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:What's happening in my stomach that makes it "rumble" when I'm hungry and why does it do that?
gpt
The digestive system is one long muscular tube going from the mouth to the anus.  It uses a system of muscular contractions, called peristalsis, to move and break down food in the tube.  Sometimes gasses get trapped among the little bits of food and digestive juices.  During peristalsis, it's the movement of these air pockets that creates the rumbling noise.  When you're hungry, your body creates hormones which trigger peristalsis.  The vibrations of your empty stomach make you hungry and the peristalsis continues moving gasses through your digestive tract, thus creating the rumbling.