How many pulmonary alveoli are supplied by a single arteriole and drained by a single venule?
A detailed measurement of histological specimens of the lungs of the cat shows that each terminal precapillary vessel (arteriole) supplies, on the average, 24.5 pulmonary alveoli; each terminal postcapillary vessel (venule) drains, on the average, 17.8 alveoli. These numbers link pulmonary alveolar blood flow in capillary sheets with the flow in pulmonary arteries and veins which are cylindrical tubes. They are key numbers needed for hemodynamic analysis. In the literature, these numbers are variously speculated to be 1 or smaller; thus our results correct, even though only for the cat, an important concept.
D000818:Animals; D001160:Arterioles / Q000033:anatomy & histology; D002415:Cats; D008297:Male; D010784:Photomicrography; D011650:Pulmonary Alveoli / Q000098:blood supply*; D014699:Venules / Q000033:anatomy & histology