Comparative Vertebrate Histology

All digestive systems perform common functions: breaking down ingested food to its constituent monomers, absorbing these monomers across the alimentary epithelium, and getting rid of indigestible components. The vertebrate digestive tract consists of a longitudinal tube through the body with a common basic wall plan; the length of the tube and the modifications in the wall depend partly on diet. Within any individual the histology of the wall varies by region along the length of the tract according to the function(s) of each region. Therefore the variations among vertebrate digestive systems can be understood by examining and comparing the regional histological structure of the mucosal, submucosal and muscular layers of the gut wall in species representative of the vertebrate groups. You should review laboratory material on the mammalian (human) digestive system (laboratory module for Gastrointestinal System, available on Anatomy and Neurobiology website for ANAT 2160/BIOL 3430).