Olfactory epithelium: structure and function
Trachea: anatomy, structure and function
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The 
trachea (or windpipe) is a 4-5 inch (= 10-12 cm) vertical tube that runs through the neck and chest, just anterior to the esophagus.
An expanded view of the trachea and esophagus. Swipe to switch between views.
- Many consider the trachea to be the first portion of the lower respiratory tract, which also includes the bronchi, bronchioles, and lungs.
- The trachea has a wide lumen (= 1 inch or 2.5 cm) and functions to conduct air between the larynx and (primary) bronchi.
- Embedded in the wall of the are 16 to 20 tracheal rings made of hyaline cartilage.
- The cartilage rings stiffen the tracheal wall so the lumen stays open during breathing.
- In the back, the rings are incomplete, giving them a characteristic C-shape.
Learn more about the structures of the respiratory system with this interactive quiz guide.
- The wall of the trachea is made up of four distinct tissue layers.
- Along the luminal surface, the trachea is lined by respiratory mucosa (or mucous membrane). Goblet cells in the pseudo-stratified ciliated columnar epithelium produce mucus, which warms, moistens, and removes foreign particles from the air as it flows through the trachea.
trachea
- Deep to the mucosa is the submucosa. Like the lamina propria, the submucosa is primarily composed of loose (= areolar) connective tissue. Many blood vessels, neurons, and glands are also present.
- The (seromucous) glands
secrete a combination of water and mucus to the luminal surface of the trachea through narrow ducts. The mucus adds to that secreted by the goblet cells.
- External to the submucosa is a cartilaginous layer containing c-shaped .
- The open end of the rings are attached by the trachealis muscle. While coughing, these smooth muscle fibers contract. This narrows the tracheal lumen and increases the velocity of airflow, which helps dislodge mucus and foreign particles.
Keep learning with these respiratory system quizzes and diagram labelling exercises.
- The outer layer of the trachea, the adventitia, is a band of loose connective tissue that loosely binds the trachea to the esophagus and other nearby organs.
- A photo micrograph shows a more realistic depiction of the layers and structures that make up the tracheal wall.
An Overview of the Trachea Location, Anatomy, and Physiology:
An Overview of the Tracheal Wall Composition and Structure:
Test yourself by observing the Tracheal Wall Composition and Structure
Interactive quiz about the trachea
Trachea Quiz: Anatomy and Function
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