The pathway for inhaling and exhaling.
Our windpipe, known as the trachea, is used as a passage way for the entrance of air and the expulsion of carbon dioxide. It is a tube attached to the larynx and is made up of both connective tissues and smooth muscles tissues. In order to keep it’s shape and to gain support on the “anterior and lateral sides of the trachea,” there are 15-20 pieces of hyaline cartilage that exists in a C-shape (Seeley, 2008, p. 832). Because of the hyaline cartilages relative strength these c-shaped pieces are able to protect and support the trachea, keeping it open for air travel. The whole trachea however is not surrounded by this hyaline cartilage. The posterior wall is made up, rather, by “elastic ligamentous membrane and bundles of smooth muscles” known as trachealis muscle. It is this muscle that allows for constriction and dilation of the trachea (Seeley, 2008, p. 832). Which means that when it comes to coughing, vomiting, or any necessary moment of serious expulsion, the constriction action of the trachealis muscle causes the air and offending particles are able to be rapidly expelled from the body. The inside of the trachea, similarly to the nasal cavity, is lined with goblet cells, which create the mucus used to capture offending particles that had been inhaled. Cilia end up moving the particles into the larynx, then the pharynx and soon after they are swallowed and destroyed.
Seeley, R. R., Tate, P., & Stephens, T. D. (2008). Anatomy and physiology (8th ed.). New York: McGraw-Hill Higher Education.