Hemorrhoids are dilated veins. They can be outside the anus where they are called external hemorrhoids, inside where they are called internal hemorrhoids, or prolapsing where they may slide in and out. Here you see the black endoscope entering the rectum, making a U-turn and looking back on itself. The large bluish nodules surrounding the endoscope are the hemorrhoids. When they bleed, these internal hemorrhoids can usually be simply treated by cautery or applying small rubber bands around them.