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Ihe Alyeol.ir Capillary Unii

RESPIRATORY PHYSIOLOGY

Type I alveolar celi Tightcell Type II alveolar celi Surface-active layer (surfactanl) and nudeus l junctions

Lamellarbodies'

Alveolar macrophage

C apillary lumen

lumen

Alwolus tairspace)

Capillary

lumen

Capillary

lumen

Alveolus

(airspacel

Interslilium

Inierstitial celi

Fused basement Type II Endothelial (loose) Endothelial celi membranę* ałveolar celi celi junctions and nucleus

Figurę 5.14 Ultrastructure of Puimonary Alveoli and Capillaries_

C.as exchange occurs ac/oss iłu* lype I alveolar cells, ihe basement    o( the capillaries and t an be found in the mterstitium of the ah/eolar

•nembrane, and Ihe capillary endothelial celi. The type II alveolar    septa or within Ihe alveolus itself. They serve to engulf inhaled partic-

:elk secrele surfactanl. which forms a thin layer over the fluid that ulates and bacteria. coats the surface of ihe ah-eolus. Alveolar macrophages migrate out

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