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The Human Phenotype Ontology (HPO) is downloaded weekly from The file downloaded is considered the "last stable build" available for the ontology. For more about the HPO, view their website at

Term:Abnormal alveolar type II pneumocyte morphology
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Accession:HP:0033245 term browser browse the term
Definition:Any structural abnormality of alveolar type 2 (ATII) cells.
Comment:Alveolar type 1 (ATI) and type 2 (ATII) cells are specialized epithelial cells of the distal lung. ATI cells are flattened squamous cells that cover around 95% of the alveolar surface and lie adjacent to capillary endothelial cells to form the pulmonary gas exchange region. ATII cells have a compact morphology and cover the remaining 5% of the alveolar surface. The ultrastructural hallmark of ATII cells is the expression of lamellar bodies containing dipalmitoylphosphatidyl choline, the major lipid component of pulmonary surfactant that reduces surface tension in the alveoli to prevent collapse of the lungs at the end of expiration. ATII cells play an important role in innate immune responses within the lung with evidence that lung surfactant proteins have anti-microbial effects and reduce inflammation caused by the inhalation of irritants.
Synonyms:exact_synonym: Abnormal alveolar epithelial type II cell morphology;   Abnormal pulmonary type II cell morphology;   Abnormal type II pneumocyte morphology

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  Human phenotype 0
    Phenotypic abnormality 0
      Abnormality of the respiratory system 0
        Abnormal respiratory system morphology 0
          Abnormal lung morphology 0
            Abnormal pulmonary alveolar system morphology 0
              Abnormal alveolar type II pneumocyte morphology 0
                Type II pneumocyte hyperplasia 0
                Type II pneumocyte hypertrophy 0
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