All the internal shots were taken from a small camera inside the body. But let's get down to the topic here. This person suffered from acute heart burn, the reason being is that most people have a little valve in their esophagus near the entrance of the stomach which prevents stomach fluids going back up. This man didn't have that, and in fact the whole passage way was enlarged.

So what they are doing here is taking a chunk of the stomach muscle and wrapping it around the esophagus to narrow the passage way and simulating a valve so he won't have to buy a life time supply of Rolaids.