Histology of Respiratory System

Histology of Respiratory System

Nasal Cavity:

a)Cutaneous region: The cutaneous region lined by a relatively thick keratinized stratified squamous epithelium. At mid vestibule the epithelium is thinner and non- keratinized. The caudal portion of cutaneous region is a transitional zone lined by an epithelium that varies, from stratified cuboidal to non- ciliate pseudostratified columnar.

b)Respiratory region: Caudal two-third of nasal cavity is considered as respiratory region except olfactory  region.The mucosa of respiratory region is lined with typical respiratory epithelium.The proprio-submucosa of nasal cavity contain numerous mucous and serous gland,quite vascular every-where and contain many large veins.

C)Olfactory region: Comprises the dorso-lateral portion of nasal cavity,including some of the surface of the ethmoid conchae,dorsal nasal meatus and nasal septum.

d)Vomaronasal organ: Located in the mucous of central portion of nasal septum,the tubular,blind ending lateral vomaro nasal organ consists of an internal epithelial duct(vomaronasal duct),a middle proprio-submucosa and an external cartilagenous support.

Paranasal sinus: The paranasal sinuses are the close cavities in the frontal maxillary,ethmoid and sphenoid bone.They are lined with thinnest respiratory epithelium that contain few goblet cells.Gland and blood vessels in proprio-submucosa are very scant.

Nasopharynx:The nasopharynx is that portion of the pharynx  that is located dorsal to the soft plate.The lining of the nasopharynx  consists mostly of respiratory epithelium but is stratified squamous epithelium.Caudodorsal portion of the soft plate.

Larynx: The larynx is lined by mucosa and parted by cartilage.The epithelial lining is stratified squamous or pseudostratified columnar.