Computerized morphometric analysis of the chick embryo esophagus

By means of a computerized morphometric system and a semiautomatic digital system (videoplan II), the quantitative aspects of the organogenesis of the chick embryo esophagus were investigated from the 6th to the 15th day of incubation. The area of the total section, of the lumen, of the wall and its components (subserous stratum, muscle layer, lamina propria and epithelium) and the thickness of the epithelium and the muscle layer were measured. The mean area +/- S.E.M. of the values obtained was calculated. The percentage of shrinkage, due to the histological procedures, was calculated for each day. The mean values for each day of incubation were modified on the basis of the shrinkage percentage. Exponential curves and r coefficient were determined to evaluate the growing pattern of the mean area of the esophageal wall components as a function of age. The main results are the following: 1) From the 6th to the 10th day of incubation the areas of all the wall components show an increase. 2) From the 11th day onwards, the wall components undergo a different growth pattern; in fact, the area of the subserous stratum decreases from the 11th to the 13th day, the muscle layer and the lamina propria show a decrease on the 12th day, while the growing pattern of the epithelium area appears irregular from the 12th day onwards. 3) The lamina propria results to be the component of the wall that shows the highest growth rate. Moreover, the esophageal anlage shows different developmental behaviour compared with that of the other intestinal tracts previously examined (ileum, duodenum, colon, caeca) in the same chick embryo.