Tunica  mucosa  of  nasal cavity, trachea, main, large, medium bronchi lined by  SIMPLE    COLUMNAR   CILIATED     PSEUDOSTRATIFIED epithelium  =  SCCP EP.
                                             Cell types in SCCP EP ( or RESPIRATORY epithelium):
1) CILIATED cells.- it are tall COLUMNAR cs with apically located  CILIA. Funct.: removal of dust particles, 2) GOBLET cs - tall COLUMNAR cs with apically located secretory GRANULES. Funct.: secretion of MUCINOGEN., 3) BASAL cs- are SHORT undifferentiated cs  Funct.:it are origin for REGENERATION., 4) BRUSH cs.- tall COLUMNAR cs with apically located MICROVILLI. Funct.: it are CHEMORECEPTORS. 5) ENDOCRINE cs (DNES cs) –it contain secretory GRANULES in basal domain. Funct.: secretion of hormones.   6) ONLY bronchioles epith. contains CLARA cs. –are columnar cs with DOME-shaped apex and apical granules. Funct.:  secretion of SURFACTANT.           It    wall is composed of 4 TUNICS:   1. Tunica mucosa,       2.Tunica submucosa,
                                                                             3. Cartilage    layer,        4.Tunica adventitia.
      Tunica  mucosa  is composed of 2 layers: A) SCCP EP.,   B) lamina propria –  loose irregular          connect. tissue =  LICT.  Tunica submucosa.- dense irregular connect. tiss., housing mucous
       glands.       Cartilage   layer  is composed of  --  16-20 HYALINE cartilage C-RINGS.
                     Tunica adventitia –is LICT.    
     Tunica  mucosa  of    1) main, 2) large and 3) medium BRONCHI is composed of 3 layers: A) SCCP  EPITH.,    B) lamina propria –LICT.,   C) muscularis mucosae  - smooth muscle cells.
        Tunica submucosa of those bronchi CONTAINS mucous glands.
2. Main (or PRIMARY) bronchi.  Wall is composed of 4 TUNICS (See”Trachea”).
     Epithelium –is  SCCP EP.
BUT:   Cartilage    layer is composed of         -- HYALINE cartilage  COMPLETE  rings.

3. Large (or SECONDARY) bronchi.  Wall is composed of 4 TUNICS (See”Trachea”).

      Epithelium-   is SCCP EP.
 BUT:    Cartilage  layer is composed of        -- HYALINE cartilage  PLATES.
4. Medium  bronchi.. Wall is composed of 4 TUNICS (See”Trachea”). Epithelium- is SCCP EP.
BUT:   Cartilage  layer is composed of          -- ELASTIC cartilage  ISLETS and GRAINS.
5.Small (or intraLOBULAR)) bronchi. Cartilage – is ABSENT. Tunica submucosa has NOT glands.
It means: only 3 tunics in the wall: 1. Tunica mucosa, 2. Tunica submucosa,  3. Tunica adventitia.                                                                       In tun. mucosa very THICK layer of smooth MUSCLE cells.  ONLY SMALL bronchi participate in attack of bronchial ASTMA, because are able to CONSTRICT after stimulation by histamine.         It  presented by: 1) respiratory BRONCHIOLES,    2) Alveolar sac,   3) ALVEOLI
           Wall of ALVEOLUS is composed of  epithelial cells and alveolar macrophages.
      Epithelium contains 2 cell types:1) pneumocyte type 1, or squamous alveolar cell. It is simple SQUAMOUS epith.   Funct.:      is gas exchange
      2) pneumocyte type 2, or  great alveolar cell. It is simple CUBOIDAL epith. Its cytoplasm  contains LAMELLAR BODIES.  Funct.:  is secretion of SURFACTANT into alveoli lumen. Surfactant prevents: a) collaps of alveoli during expiration, b) pulmonary edema.
      3) Alveolar macrophage, or dust cell. It is STAR-shaped cell (with cytoplasmic processes; too many lysosomes).   Funct.:  phagocytosis of dust particles and bacteria.
Embryonic origin for respiratory epithelium (ciliated cs, goblet cs..) and alveolar PNEUMOCYTES—is ENDOderm of foregut.         For smooth muscle cs, cartilage, LICT – is  mesenchyme. For   alveolar macrophages –-  is  monocyte.