title: Growth of pulmonary circulation in normal pig--structural analysis and cardiopulmonary function.
abstract: Morphometric analysis of the postnatal development of the pig lung, with emphasis on alveoli and vessels, shows features of growth similar to man, but occurring at a much faster rate in the pig, which telescopes in the first 3 mo the changes seen in human childhood and adolescence. During the first weeks, arteries (birth to 2 wk) and alveoli (1--12 wk) increase in number, whereas increase in size continues until adulthood. Wall thickness decreases soon after birth in arteries 15--200 micrometer, and by 8 wk in those 200-1,000 micrometer. At this age the adult left ventricular predominance in weight is already present. Throughout growth the venous wall thickness does not change. Cardiopulmonary function studies in pigs, from 2 to 16 wk, show that, during the period of rapid postnatal lung growth, there is no change in tidal volume, dynamic compliance, and thoracic gas volume as related to body weight; right ventricular and pulmonary arterial pressures also remain unchanged, whereas pulmonary vascular resistance decreases during the 1st mo.
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001158:Arteries / Q000254:growth & development; D001980:Bronchi / Q000254:growth & development; D005260:Female; D008168:Lung / Q000098:blood supply / Q000254:growth & development* / Q000502:physiology; D008297:Male; D011650:Pulmonary Alveoli / Q000254:growth & development; D011652:Pulmonary Circulation; D012119:Respiration; D013552:Swine / Q000254:growth & development*; D014680:Veins / Q000254:growth & development