has part has part has_part characteristic of has modifier pulmonary alveolar type 1 cell decreased type I pneumocyte number absent type I pneumocytes absent membranous pneumocytes absent type I pneumonocytes absent ATI 2011-02-11T02:44:08Z absent squamous alveolar lining cell CL:0002062 absent AT1 absent type 1 alveolar epithelial cells absent Type 1 pneumocyte csmith absent squamous alveolar cell absent lung type 1 cells absent type I alveolar epithelial cells FMA:62500 absent Pulmonary alveolar type I cell absent type I cells MP:0010817 MPheno.ontology absence of the flattened, branched squamous cells that covers more than 98 percent of the alveolar surface, and have thin (50-100 nm) cytoplasmic extensions to form the air-blood barrier essential for normal gas exchange absent small alveolar cells abnormal absent