Pseudostratified Columnar Epithelium

Pseudostratified Columnar Epithelium

The cells of pseudostratifed columnar epithelium appear to be straiitied or layered, but they are not The layered eflect occurs because nuclei are located at two or more levels within the cells of the tissue. However the cells, which van, in shape all reach the basement membrane, even though some of them may not contact the free surface.
 

These cells commonly possess microscopic hairlike projections called cilia which measure 7 -10 micro meter in length. They extend from the free surfaces of the cells, moving constantly Goblet cells are also scattered throughout this tissue, and the mucus they secrete is swept along by the activity of the cilia.
 

Pseudostratified columnar epithelium is found lining the passages of the respiratory system and in various tubes of the reproductive systems. In the respiratory passages, the mucus-covered linings are sticky and tend to trap particles of dust and microorganisms that enter with the air. The cilia move the mucus and its captured particles upward and out of the airways. In the reproductive tubes, the cilia aid in moving sex cells from one region to another.