What is the significance of the fact that human tracheal cartilage rings are incomplete posteriorly? Why is tracheal epithelium is said to be stratified?
The 'c' shaped cartilage rings are present in the trachea to prevent it from collapsing and they keep the trachea open for air to come in and out. In humans there are about 15 – 20 incomplete C-shaped cartilaginous rings which reinforces the anterior and lateral sides of the trachea to protect and maintain the airway open. (The cartilaginous rings are incomplete because this allows the trachea to collapse slightly to allow food to pass down the esophagus.)
Tracheal epithelium is said to be stratified because the epithelium is made up of more than one layer. It is Pseudostratified ciliated columnar epithelium having cilia on its free surface