Human: What is a stoma, and how is it formed? Assistant: 
A stoma is an opening in the body that allows waste to pass through. It is usually created surgically and can be used for a variety of medical reasons, such as draining fluid from the abdomen or bladder. The stoma is often made up of two parts: the stoma itself, which is the opening in the skin, and the stoma appliance, which is the device that attaches to the stoma. The stoma appliance helps protect the stoma from irritation, infection, and damage.