And if your stomach is growling, it’s digesting on empty. After receiving “begin digestion” signals from your brain, the muscles begin moving and mixing the digestive juices in stomach. That produces vibrations – more commonly known as those growling sounds.

The human stomach is a muscular, elastic, j-shaped bag. It produces a new layer of mucus every two weeks in preventing it from digesting itself. And when you blush, the lining of your stomach also turns red.

It is about 12 inch long and 6 inch wide, at its widest point. Since the stomach has the ability to expand, the volume of the human stomach varies from person to person. Competitive eaters often try and stretch their stomachs by drinking large amounts of water at a time.

Compiled by Tony Yeung/Toronto Star Library

Illustration by Raffi Anderian