The bronchial tree and branches of the pulmonary artery (human, adult, posterior aspect)

Resin corrosion cast of left and right lung. Posterior aspect of lower trachea (1, yellow) with two principal bronchi (yellow) with red-stained pulmonary artery (2) and its branching. The cast of both lung lobes reveals especially the intricate divisions and branching of the bronchial tree (yellow) as well as their close relation to their vascularisation (red).