Alveoli
- single celled air sacs at the very end of the dividing air tubes in the lungs
- the actual location of gas exchange
- over 600 million in the human body
- Grouped together into alveolar sacs
- surrounded by capillary blood vessels which absorb oxygen from the alveoli and release carbon dioxide
The Respiratory Epithelium
- a layer of cells lining the pathways to the lungs which serve to produce mucus, and move particles out of the airways.
Ciliated Cells
- cells on the outside of the respiratory epithelium which use cilia to move mucus and particles out of the respiratory tract to be coughed out.
Goblet Cells
- produce mucus which lines the respiratory tract and traps bacteria and other particles in the air.
Basal Cells
- serve as epithelial stem cells, they can differentiate into other types of epithelial cells, and often move to damaged sections to restore healthy epithelial tissue.