Concepedia

Morphometry of the small pulmonary arteries in man.

Circulation Research · 1978 · 182 citations · 5 references

TL;DR

The study measured diameter, length, and branching of pulmonary arteries from 10 to 300 µm using resin casts and histological sections of ink‑gelatin–injected lungs. The measurements confirmed that branching rules extend to arteries as small as 10–15 µm, yielding an estimated 73 million such vessels, and showed that capillaries arise directly or via numerous precapillaries from these small arteries.

Abstract

From a resin cast of a normal pulmonary arterial tree, the diameter, length, and number of branches in each order were determined for arteries from 25 to 300 micrometer in diameter. Histological sections 120-micrometer thick were cut from a normal human lung in which the pulmonary artery had been injected with a mixture of ink and gelatin. Similar measurements were made on arteries from 10 to 70 micrometer in diameter, and the mode of origin of the capillaries was studied. The data thus obtained were found to correspond reasonably well to values previously estimated by extrapolation from data for arteries of 100 micrometer or more in diameter. The branching rules apply down to arteries of about 10-15 micrometer in diameter, the estimated number of which is 73 million. Distal to these vessels, capillaries arise either directly from small arteries or indirectly via precapillaries which are given off in great numbers and diverse patterns from the small arteries