3.Adventitia????B. The nasal cavity proper is the larger, narrower, posterior portion of cavity.Thus, in the respiratory epithelium of smokers, more goblet cells appear in response to higher levels of inhaled air pollution, while the number of ciliated cells decreases under the influence of carbon monoxide.The lamina propria consists of loose connective tissue, contains mucous glands in the upper airways (from the nasal cavity to the bronchi).The skeletal connective tissue (cartilage and bone tissue) that provides the framework for the airways is present in the nasa cavity and only cartilage tissue in the larynx, trachea and bronchi.As the diamete of the bronchi decreases, the amount of the cartilage tissue gradually decreases, and the cartilage completely disappears at the level of the bronchioles.In the initial region of the vestibule there are se and sweat glands, as well as short thick hair, vibrissae, which filter large p from the inhaled air.Posteriorly, the epithelium changes to stratified squa non-keratinized, and when moving into the nasal cavity proper, to the res epithelium.The thickness of the muscle layer graduall- decreases, disappearing at the level of the alveolar ducts.3 CONDUCTING PORTION

3.1 Nasal cavity

The nasal septum divides the nasal cavity into two chambers.The nasal cavi includes the vestibule and the nasal cavity proper, which differ in the loca size and structure of the walls.The vestibule i by stratified squamous keratinized epithelium as a continuation of the epid.Smooth muscle tissue appears at the level of the trachea, where it connects the es of the C-shaped cartilages.A. The vestibule is a smaller but wider part of the nasal cavity located ant just behind the nostrils.It is lined by respiratory epithelium, in its underlying lamina prop

7As you remember from the epithelium tissues classes, the epithelium can undergo metaplasia in response to a change in the microenvironment.These changes can lead to impaired patency of the small airways but are reversible.The content of elastic fibers increases towards the alveoli.3.Adventitia is composed of loose connective tissue.The wall of the bronchi is surrounded in a spiral by many layers of smooth muscle cells.Fibromusculocartilagineous layer.Its framework is made by cartilage.covering the external nose.2.