Microradiography of pulmonary arterioles, capillaries, and venules of the rabbit

Abstract

Pulmonary vessels of excised rabbit lungs were injected with a suspension of barium sulfate in gelatin. Slices 50 μ thick were radiographed at 5 kv and 2 ma using high resolution spectroscopic plates. When these plates were viewed through a microscope, pulmonary arterioles, venules and capillaries were identified. Arterioles show relatively regular branching at right angles. The capillary bed fills from short (10–20 μ long), thin (10–15 μ diameter) precapillaries arising at right angles from arterioles. The alveolar capillary network freely communicates with networks of adjacent alveoli. Several capillaries draining alveolar nets usually join forming a vessel which is broader at its origin than its insertion into a venule. These vessels, designated collecting venules join the venule at acute angler Clear differentiation of small venous vessels from adjacent small arterial vessels is possible. The capillary network between an arteriole and venule appears to span at least two alveoli.