The goblet cells are filled with blue mucoid secretion which is being poured into the narrow lumens. The central cavity in the picture is a blood vessel with endothelium, surrounded by a very cellular connective tissue. Separating this connective tissue from the epithelium is a thin blue layer of connective tissue fibers. Slide 15 Pseudostratified ciliated columnar epithelium from the trachea. Nuclei are at different levels.
All cells touch the basement membrane, but only the taller cells reach the lumen.
The cilia are longer and less regular than the microvilli of a striated border. Slide 16 Pseudostratified ciliated columnar epithelium with pale goblet cells. The different levels of nuclei are clearer here. Again, notice the wavy-looking cilia. Surface view of cilia with scanning EM scope.