Snake intestine. Coloured scanning electron micrograph (SEM) of a freeze-fracture through the intestine of a snake. The mucosa (pink) is pseudostratified and has cuboidal absorptive cells covered in short microvilli. Some goblet cells are also seen. The intestinal surface is orange. The thickness of the mucosa alters during fasting and eating. The submucosa (green) of connective tissue includes blood vessels, in which red blood cells (red) are seen. Magnification: x1000 when printed at 10 centimetres across.