Which of the following not true about alveolar lining?
High-Yield Explanation
The alveoli contain two types of epithelial cells. Type I cells are flat cells with large cytoplasmic extensions and are the primary lining cells of the alveoli, covering approximately 95% of the alveolar epithelial surface area. Type II cells (granular pneumocytes) are thicker and contain numerous lamellar inclusion bodies. A primary function of these cells is to secrete surfactant; however, they are also impoant in alveolar repair as well as other cellular physiology. Although these cells make up approximately 5% of the surface area, they represent approximately 60% of the epithelial cells in the alveoli. Ref: Ganong's Review of Medical Physiology 23rd edition, Chapter 35.