.title Let's take a look up our nostrils
.fg 20
.c;^&Let's Take A Look Up Our Nostrils\&
.s
.c;Michael A. Sterner
.nmpg 1
.page
.;
.ap
	Hello, good afternoon, and welcome to "Let's Take A Look Up Our 
Nostrils." I'm your host, Arthur Pontiac, and let's get right down to some 
olfaction action. This week, Section V, "Cilia."
	As we all know, cavities with rigid walls, such as the nasal fossae 
and the paranasal sinuses rely heavily on ciliary action for the removal of 
debris and bacteria from their lumen. There are, of course, limits to the 
powers of cilia. Sometimes other methods of expulsion must be found, such as
sneezing (demonstrates with bottle and kleenex).
	But lets get back to those silly cilia. Each cilium contains 
longitudinal filaments in a cylindrical column of protoplasm, which in turn is 
surrounded by a membrane. The central paired filaments are arranged side-by-
side; this determines pendular movement in a direction at right angles to 
their axis. All the central paired filaments are in the same plane, which 
causes all the cilia to bend in the same direction and not to strike against 
one another.
	In conclusion, the nose is lined over a small area with olfactory 
epithelium and over its greater part with ciliated epithelium. Almost all of 
the surface of the nasal fossae and sinuses is thus protected, by ciliary 
action and in those parts where no cilia are present, the drag from behind on 
the viscous covering of mucous removes debris and bacteria, conveying all 
deleterious matter to the naso-pharynx, whence it is carried to the stomach by 
swallowing movements, with subsequent destruction of bacteria by gastric 
juices.
	Well, that's all this week for "Let's Take A Look Up Our Nostrils."
Be sure and join us next time when we will move on to section VI, "The
Exchange of Fluid in the Nose and Upper Respiratory Tract." 
	Goodnight.