Figure 5. Keratin 5 positive cells in the epithelium lining of the middle ear cavity.

(a–c) A cross section in the ciliated epithelium of the middle ear cavity, showing the presence of basal cells that are positive for Keratin 5 (K5, red)) and Keratin 14 (K14, green) (a,b,b’). DNA was stained by Hoechst (blue). (b’) is a larger view of a region in (b) marked by a * that appears to be a Goblet cell. Note that K5 also labeled the apparent Goblet cell while K14 did not. A TEM graph of the ciliated epithelium region revealed the high resolution cellular structure of the epithelium, consisting of the basal, ciliated, and Goblet cells (c). Note the distinct “goblet”-shaped morphology (b,b’,c) and the presence of numerous secretory vesicles in the Goblet cell (c). Note also that the Goblet cells do not contain cilia basal bodies or axoneme (b,b’,c), while thinner sections of microvilli of the Goblet cell are visible (c). Scale: 20 μm (a,b); 2 μm (c). (d–e) A cross section in the non-ciliated epithelium of the middle ear cavity, revealing a single layer of squamous epithelial cells that are positive for Keratin 5. (e’) is a larger view of a region in (e) Scale: 20 μm.