The Respiratory System


The Larynx, sometimes called the voice box, or adams apple, is a portion of the air passage below the pharynx and above the trachea. The larynx has several cartilages. A large plate of cartilage, the thyroid cartilage, surrounds the front and sides, making up most of the frame. Beneath the thyroid cartilage is the cricoid cartilage. The cricoid is a complete ring of cartilage which is narrower in the front and broader in the back. Some smaller cartilages, the arytenoid cartilages, which are capped by the corniculate cartilages, are attached to the vocal folds and are involved in controlling the tension on the vocal folds.

The paired vocal cords are bilaterally situated, bordering the air passage inside, near the glottis, and just below paired lateral folds of the upper trachea called ventricular folds or false vocal folds.


The trachea extends from the larynx to the left and right primary bronchi branches of the airway. Along its lenth there are a series of C-shaped cartilages around the trachea with the gap of the C to the posterior side. The cartilages support the wall and keep the airway open.

The pseudostratified columnar cells of the epithelial lining are ciliated. These cilia work to move dust and debris from the air passage to the pharynx, where it can be swallowed.

The submucosa of the trachea has an abundance of glands which secrete both watery and mucous laden fluids. Beyond the submucosa is a muscularis layer with both the cartilage and smooth muscle.





































Overview of Respiratory System

Human Nasal Passages

Human Pharynx Regions

Human Larynx and Trachea

Human Bronchi and Lungs

Muscles of Human Respiration

Lower Respiratory Development

Fish Lungs/Air Bladders

Tetrapod Lungs

Lung Ventilation Systems

Gills of Vertebrate Animals

Things I Should Know