#115 Gallbladder, Human. H&E

Why do the nuclei appear at different levels in tangential sections? Depending on the orientation of the tissue during sectioning, the orientation of the cells on the slide can appear different than the orientation of the cells in tissue.

#101 Small intestine (PAS and hematoxylin)

What is the basis for the PAS stain? Most carbohydrates react with periodic acid to produce aldehydes, which convert the colorless Schiff reagent to pink, or magenta
h2. #102 Small intestine, (Bodian/silver)
What types of intercellular junctions are commonly found in epithelia? Junctional complexes (tight junctions plus zonula adherens), desmosomes, gap junctions

#5 Trachea

Identify the two major types of cell that reach the lumen. What are their characteristics? Simple columnar ciliated epithelial cells and goblet cells (appear empty). What is responsible for the eosinophilic line at the apex of the majority of the cells? Basal bodies

h2. #33 Esophagus, H&E

Which part of the slide image corresponds to the esophageal lumen? The bottom of the image would correspond to lumen of the esophagus because the epithelium is oriented facing the bottom of the image.