When I ask kids where their stomach is, most point to their bellybutton. In reality, your stomach is higher up in the abdomen. Half of your stomach is tucked under your rib cage on the left. The other half lies in the middle of your body about four inches above the bellybutton. If you get a stomachache near your bellybutton, the pain is typically coming from your intestines. A true stomachache usually hurts below the sternum, or breastbone.

Stomachs have a lot in common with bagpipes — without the “pipes” sticking out of them. They both resemble a big pouch. They both need to be squeezed to get the job done. They both make awful sounds if they’re not working properly.

If you examined the inside lining of a stomach, you would find hundreds of ridges and millions of tiny pits called gastric glands. (Gastric is the medical word for stomach.)

When you eat, hydrochloric acid oozes out of the gastric pits like a volcano spewing lava. Although hydrochloric acid isn’t as hot as molten rock, it’s strong enough to dissolve metal. (Please don’t test this at home.) Gastric glands also produce a chemical called pepsin that breaks down the protein in your diet.

By the time your stomach is done having its way with your lunch, it squeezes what’s left, a partially digested goo called chyme (pronounced kime), into the small intestine. Depending on how much water you’ve had to drink, chyme can be the consistency of a paste or a liquid.

Your stomach is lined with millions of mucus glands. The glands secrete a thick goo that creates a thin but potent barrier against the digestive enzymes it produces.

Even with protective mucus, digestive juices can irritate the lining of the stomach. For this reason, the stomach replaces its lining once every seven days. Compare that to your top layer of skin, which is replaced once every 30 days.

In addition to being a chemical factory, the stomach contains three layers of muscle to efficiently grind up what you’ve eaten. By efficiently mixing stomach contents, what you’ve eaten is fully exposed to pepsin and hydrochloric acid. If you’ve ever made a cake, you know how hard it is to get the egg, butter and oil to mix thoroughly into the cake batter. Your stomach does this like a pro.

Have you ever had a stomachache from taking too much ibuprofen? This happens because one of the side effects of ibuprofen is that it reduces stomach mucus production. The reason you’re supposed to take ibuprofen with food is because eating increases stomach mucus production, which can reduce the side effects of the medication.

Fun fact: Little kids usually tell me they grew in their mom’s stomach before they were born. While cute, this is not true. Babies grow inside a special organ called the uterus. If they were actually in their mom’s stomach, they would be digested like a piece of cheese.

Bennett is a Washington pediatrician and frequent KidsPost contributor.