Stereo architecture of the lamina propria in the mouse laryngopharynx in scanning electron microscopy.

In the ventral wall of the mouse laryngopharynx, a fairly large number of the epithelial papillae containing taste bud (provisionally denominated the pharyngeal papillae) were observed. The NaOH cellmaceration method was applied in order to demonstrate the stereo architecture of the connective tissue papillae (CTP) of the pharyngeal papillae. The CTP appeared as a cylindrical wall surrounding a round depression, and consisted of a delicate meshwork of collagen fibrils. It is suggested that the CTP constitute the skeletal framework of the pharyngeal papillae and that the round depression corresponds to the site of taste bud. Furthermore, the collagen fibrillar architecture in the extrapapillary region appeared to be arranged to meet specific functional needs. That is, in the rostral end of the laryngopharynx, the collagen fibrils ran solitarily to form a coarse meshwork and seemed to allow the epithelium a certain degree of freedom of motion in swallowing. On the other hand, in the caudal part the fibrils concentrated into the thick bundles of the fibers running side by side along the long axis of the laryngopharynx and, therefore, appeared to play an important role in resisting the excessive stretching force.