Scanning electron micrograph (SEM) of an absorptive epithelial cell in the small intestine, showing the parallel arrangement of numerous microvilli that project into the interior lumen of the intestine. The vast surface area provided by the microvilli increases absorption of ingested substances. The deep etching technique used to prepare the specimen also shows the network of microfilaments that radiate from the base, and extend into the core, of each microvillus. The filaments contain the contractile proteins actin & myosin (found in muscle cells), which gives some motility to the microvillus border.