Endoderm

Endoderm Derivatives

Gut, liver, pancreas, lungs, trachea

Trachea/Esophagus Separation

Wnt → β-catenin → separates tubes

Tracheoesophageal Fistula

Failure of separation → airway/digestive issues

Surfactant

Reduces surface tension → prevents alveolar collapse

Premature Infants

Lack surfactant → respiratory distress

Mesenchyme Role (Lung)

Controls epithelial fate via signaling

Emphysema

Alveoli destroyed → ↓ gas exchange

Chronic Bronchitis

Mucus + inflammation → blocked airflow

COPD

Overall reduced oxygen exchange

Mesothelioma

Asbestos → scarring + cancer

Black Lung

Coal dust → fibrosis

Popcorn Lung

Chemical damage → airway obstruction

ARDS

Fluid in alveoli → oxygen cannot enter blood