These links describe numerous GI conditions in patient-friendly terms.
Nowhere in Gray's Anatomy's 1,257 pages will be found a diagram of the tummy. Yet that's the nonspecific area where pediatricians are often told that it hurts. Tummy aches can range from GERD to food poisoning to allergies to a bacterial infection. There's even a chance it's a serious medical condition, as in this month's Puzzler, "Episodic pain in a school-aged child". Antacids, staying away from certain foods, and a few days of time will heal some of these ills. These links below describe numerous common GI conditions, in patient-friendly terms.