Human: My doctor wants me to get a colonoscopy, but I don't know what it is. What is a colonoscopy and why is it important? Assistant: 
A colonoscopy is an examination of the large intestine (colon) using a thin, flexible tube called an endoscope. It is used to diagnose and treat certain conditions in the digestive system. The procedure involves inserting the endoscope into the rectum and slowly advancing it through the entire length of the colon. During the exam, doctors can view the lining of the colon, remove any polyps or other growths, and take biopsies for further analysis. This helps them determine if there are any signs of cancer or other diseases. Colonoscopies are also useful for screening for inflammatory bowel disease, irritable bowel syndrome, and celiac disease.