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Conduction system

Zones and Cells

trachea

graph TD
    x{layers of trachea} ==>|from lumen| x1[mucosa];
    x ==>x2[sub-mucosa];
    x ==>x3[Adventia];
    x1==> x1a[Epithelium, basement membrane ];
    x1 ==>x1b[lamina properia = migratory cells]
    x2 ==>x2a[hyaline cartilage cshaped with trachealis muscle at side of
    esophagus for compression during swal:octicons-arrow-down-24:ing food
    , special mucus
    gland];
    x3==>x3a[dense irregular connective tissue for attachment];

Bronchi

graph TD
    X{layer of Bronchi }==>x1[mucosa];
    x1 ==>x1a[EespirRespiratory Epithelium, basement membrane, lamuna propria BALT ];
    X==>x2[submucosa];
    x2 ==>x2a[specialized mucosal glands , <mark>irregular hyaline cartilage,Circular
    smooth muscles</mark>];
    X ==>x3[adventia];

"Asthma

Abnormal constriction of Smooth muscles in intra pulmonart Bronchi to allergens

Bronchioles

Bronchioles and Alveolar ducts

Bronchi bronchioles Alveoli ducts
mucosa Pseudo-stratified ciliated Columnar Epithelium,goblet cells Simple ciliated cuboidal,Epithelium,clue cells simple squamous epithelium,Simple Cuboidal ,ALveolar Free MAcrophages
submucosa gland , hyaline cartilage, smooth muscles no gland ,no cartilage,only smooth muscle none

Bronchioles to Alveoli

graph TD
    X{bronchi}==>|Pseudo-stratified ciliated epithelium to ciliated Cuboidal
    epithelium| 1[terminal Bronchioles];
    1 ==>2[Respiratory Bronchioles = terminal bronchiole with a alveoli];
    2 ==>|transition from ciliated cuboidal to simple squamous| 3[Alveolar duct];
    3 ==>|sac like | 4[alveolar sac];
    4 ==> 5[Alveoli ];

Alveoli

Alveoli cells

graph LR
    X{cell composition of Alveoli }==>|cell covering| 1(Type 1 pneumocytes=Simple squamous
    Epithelium and basement membrane);
    X ==>| special cell scattered | 2(Type 2 pnuemocytes = Simple cuboidal
    Epithelium and basement membrane);
    2 ==>|produces <mark>surfactant</mark>| 2a[prevent alveolar collapse ];
    2==>2b[<mark>regenerate to Type 1 pneumocytes</mark>]

Route of Diffusion (O2 from air to Blood):

  1. from air to surfactant
  2. surfactant to alveolar squamous epithelium
  3. alveolar squamous epithelium to alveolar squamous basement membrane
  4. Alveolar basement membrane to endothelium basement
  5. endothelium basement membrane to endothelium cell Cytoplasm
  6. endothelium to blood

Sufficient air blood interaction needed for Gas exchange....

Emphysema From COPD

COPD (smoking => Constriction of Bronchioles) —-> Emphysema (enlargement of alveolar walls due to constriction of Bronchioles and destruction of wall by Antitrypsin deficiency ) ==> decrease in Gas exchange between blood And air...

Macrophages

graph TD 
    X{Macrophages Types} ==> X1[Alveolar Macrophages = Alveolar lumen];
    X1 ==>|Funtion| x1a[eat up dust and foreign particles,
    Microbes
    RBC in Heart failure];
    x1a ==>|Some macrophages | x1ab[ leave via mucus to pharynx];
    X ==> X2[Septal Macrophages=between septal connective tissue];
    X2 ==>|function| x2a[eat up foreigners and move to Alveolar Blood vessels Septum];

Cystic Fibrosis

Defect in CFTR gene for chloride channel in epithelium —-> Mucus with lot of Na ion and no Chloride ion —-> which attracts water ===> Viscid mucus that obstructs Bronchioles

Black Lungs on Smoker

Due to Septal macrophages in the Connective Tissue