Larynx begins the lower respiratory tract (Fig. 17-1) and is closed by the epiglottis which prevents inspired air from entering the esophagus and food/fluid from entering the trachea; permits production of sounds.

Slide 7 has a longitudinal section extending through the larynx into trachea. The section is similar to the right side of the example shown here and in Fig. 17-4.

Examine the epithelium along this tissue

• Note the change from stratified squamous to pseudostratified, ciliated (or respiratory epithelium).
• The protrusion with the large mass of muscle represents one of the true vocal cords and the protrusion that consists mostly of areolar support tissue is an edge of a false vocal cord.
• Note the cartilage plates and skeletal muscles of the larynx and the thyroid gland tissue where the trachea begins.

What type of cartilage is found in the larynx?

What histological differences occur between the true and the false vocal cords?

Now for the trachea.