Case Ih Quotes

An infection or inflammation of the larynx is known as laryngitis (lar-in-JI .-tis). It commonly affects the vibrational qualities of the vocal folds. Hoarseness is the most familiar result. Mild cases are temporary and seldom serious. However, bacterial or viral infections of the epiglottis can be very dangerous. The resulting swelling may close the glottis and cause suffocation. This condition, acute epiglottitis (ep-ih-glot-TI .-tis), can develop rapidly after a bacterial infection of the throat. Young children are most likely to be affected. The Trachea The trachea (TRA .-ke.-uh), or windpipe, is a tough, flexible tube with a diameter of about 2.5 cm (1 in.) and a length of about 11 cm (4.33 in.) (Figure 23–6). The trachea begins anterior to vertebra C6 in a ligamentous attachment to the cricoid cartilage. It ends in the mediastinum, at the level of vertebra T5, where it branches to form the right and left main bronchi. The epithelium of the trachea is continuous with that of the larynx. The mucosa of the trachea resembles that of the nasal cavity and nasopharynx (look back at Figure 23–2a). The submucosa (sub-mu.-KO .-suh), a thick layer of connective tissue, surrounds the mucosa. The submucosa contains tracheal glands whose mucous secretions reach the tracheal lumen through a number of short ducts. The trachea contains 15–20 tracheal cartilages that stiffen the tracheal walls and protect the airway (see Figure 23–6a). They also prevent it from collapsing or overexpanding as pressure changes in the respiratory system. Each tracheal cartilage is C-shaped. The closed portion of the C protects the anterior and lateral surfaces of the trachea. The open portion of the C faces posteriorly, toward the esophagus (see Figure 23–6b). Because these cartilages are not continuous, the posterior tracheal wall can easily distort when you swallow, allowing large masses of food to pass through the esophagus. An elastic anular ligament and the trachealis, a band of smooth muscle, connect the ends of each tracheal cartilage (see Figure 23–6b). Contraction of the trachealis reduces the diameter of the trachea. This narrowing increases the tube’s resistance to airflow. The normal diameter of the trachea changes from moment to moment, primarily under the control of the sympathetic division of the ANS. Sympathetic stimulation increases the diameter of the trachea and makes it easier to move large volumes of air along the respiratory passageways.