Final answer:
Intussusception is a gastrointestinal disease of childhood where a piece of bowel goes backward inside itself forming an obstruction. Symptoms include severe abdominal pain, vomiting, and bowel movements that contain blood or mucus.
Step-by-step explanation:
The gastrointestinal disease of childhood where a piece of bowel goes backward inside itself forming an obstruction is called intussusception. Intussusception occurs when one part of the intestine slips into another part, like a telescope. This can cause a blockage and lead to symptoms such as severe abdominal pain, vomiting, and bowel movements that contain blood or mucus.