Simple columnar epithelium

These large epithelial cells are specialized for absorption, and are commonly found in areas where there is considerable wear and tear, such as the digestive tract. We will examine this tissue in a cross section of the intestine of the amphibian Amphiuma. Examine the slide at low power to identify the outer layer of the villi. This is the simple columnar epithelium.

Then examine this layer at high power. The pink cells scattered among the epithelial cells are mucous-secreting goblet cells. Compare the appearance of the layer of columnar epithelial cells lining the lumen of the intestine with the idealized diagram below. Notice that the nuclei (stained purple) are all located near the basement membrane. Are all the cells identical? What specializations you see in some of these cells?

Since one of the functions of the intestine is absorption, an adaptation of the free surface of these epithelial cells is the presence of microvilli. What do these structures accomplish?