The jejunum functions in the absorption of nutrients as foodstuff travels along the gastrointestinal tract via peristalsis. The surface area available for such absorption is greatly increased by the presence of numerous tiny projections termed villi along the intestinal mucus membrane. Specialized goblet cells located in the epithelium secrete mucus that helps ease the movement of material through the tubular organ. The number of goblet cells located in the jejunum, however, is notably smaller than the number present in the ileum.

The rat jejunum tissue section illustrated in the digital image above was labeled with wheat germ agglutinin (WGA) conjugated to Oregon Green 488. WGA, which selectively binds to N-acetylglucosamine and N-acetylneuraminic (sialic acid) residues, is well suited for staining the Golgi network in fixed cells and tissues since a number of proteins and lipids found in the Golgi apparatus are glycosylated. The specimen was also labeled with Alexa Fluor 568 conjugated to phalloidin (targeting F-actin) and Hoechst 33342 (targeting DNA in the nucleus). Images were recorded in grayscale with a 12-bit digital camera coupled to a Nikon Eclipse 80i microscope equipped with bandpass emission fluorescence filter optical blocks. During the processing stage, individual image channels were pseudocolored with RGB values corresponding to each of the fluorophore emission spectral profiles.