![This is blank.](https://digitalhistology.org/wp-content/themes/histology-unified/imgs/trans.png)
Mucus-secreting tubule
The presence of mucin granules in the cells of this mucus-secreting tubule accounts for their foamy appearance seen with the light microscope. The granules contain mucin proteins which become hydrated to form mucus after their release. Trachea 5000x
![Mucin granules <p>The presence of mucin granules in the cells of this mucus-secreting tubule accounts for their foamy appearance seen with the light microscope. The granules contain mucin proteins which become hydrated to form mucus after their release. Trachea 5000x</p>](https://digitalhistology.org/wp-content/uploads/2017/06/T.E.Gl_.Ex_.Comp-19-1-ping.png)
Mucin granules
The presence of mucin granules in the cells of this mucus-secreting tubule accounts for their foamy appearance seen with the light microscope. The granules contain mucin proteins which become hydrated to form mucus after their release. Trachea 5000x
![RER <p>The presence of mucin granules in the cells of this mucus-secreting tubule accounts for their foamy appearance seen with the light microscope. The granules contain mucin proteins which become hydrated to form mucus after their release. Trachea 5000x</p>](https://digitalhistology.org/wp-content/uploads/2019/01/T.E.Gl_.Ex_.Comp-19-2-ping.png)
RER
The presence of mucin granules in the cells of this mucus-secreting tubule accounts for their foamy appearance seen with the light microscope. The granules contain mucin proteins which become hydrated to form mucus after their release. Trachea 5000x
![Nuclei <p>The presence of mucin granules in the cells of this mucus-secreting tubule accounts for their foamy appearance seen with the light microscope. The granules contain mucin proteins which become hydrated to form mucus after their release. Trachea 5000x</p>](https://digitalhistology.org/wp-content/uploads/2017/06/T.E.Gl_.Ex_.Comp-19-3-ping.png)
Nuclei
The presence of mucin granules in the cells of this mucus-secreting tubule accounts for their foamy appearance seen with the light microscope. The granules contain mucin proteins which become hydrated to form mucus after their release. Trachea 5000x
![Lumen with mucus <p>The presence of mucin granules in the cells of this mucus-secreting tubule accounts for their foamy appearance seen with the light microscope. The granules contain mucin proteins which become hydrated to form mucus after their release. Trachea 5000x</p>](https://digitalhistology.org/wp-content/uploads/2017/06/T.E.Gl_.Ex_.Comp-19-4-ping.png)
Lumen with mucus
The presence of mucin granules in the cells of this mucus-secreting tubule accounts for their foamy appearance seen with the light microscope. The granules contain mucin proteins which become hydrated to form mucus after their release. Trachea 5000x
![Capillary with red blood cell <p>The presence of mucin granules in the cells of this mucus-secreting tubule accounts for their foamy appearance seen with the light microscope. The granules contain mucin proteins which become hydrated to form mucus after their release. Trachea 5000x</p>](https://digitalhistology.org/wp-content/uploads/2017/06/T.E.Gl_.Ex_.Comp-19-5-ping.png)
Capillary with red blood cell
The presence of mucin granules in the cells of this mucus-secreting tubule accounts for their foamy appearance seen with the light microscope. The granules contain mucin proteins which become hydrated to form mucus after their release. Trachea 5000x