lamina propria of trachea

The tracheal lamina propria lies beneath the pseudostratified ciliated columnar epithelium (respiratory epithelium) and contains elastic fibers, glands, and immune cells adapted for airway defense. It is part of the respiratory mucosa and directly overlies the tracheal cartilage rings and trachealis muscle.

The tracheal lamina propria and submucosa contain mucous and serous glands (tracheal glands) that produce the mucus layer essential for mucociliary clearance. Cilia on the overlying epithelium beat in coordinated waves to propel mucus — along with trapped particles and pathogens — upward toward the pharynx.

The tracheal lamina propria houses dendritic cells, mast cells, lymphocytes, and IgA-secreting plasma cells that form the first line of immune defense against inhaled pathogens. It also contains sensory nerve endings that trigger cough reflexes in response to irritants.