<prompt> All are the histological features of Pulmonary hypeension -Capillaritis of alveolar septaSaddle thrombi in pulmonary trunkThrombi in pulmonary vasculatureAll  <response>: Ans. is c i.e., Thrombi in pulmonary vasculature Pulmonary Hypeension o In pulmonary hypeension pathological changes are seen from main pulmonary aeries to aerioles. They are : a Aerioles and small pulmonary aeries : i Medial hyperophy ii Thickening and reduplication of elastic lamina. iii Plexiform pulmonary aeriopathy in which intraluminal tuft of capillary formation occurs in dilated thin walled aeriolar branches. b Medium sized Pulmonary aeries : i Medial hyperophy; which is not marked in secondary pulmonary hypeension. ii Concentric intimal thickening iii Adventitial fibrosis iv Thickening and reduplication of elastic laminae. c Large Pulmonary aeries : o Atheromatous deposits o Vasoocclusive disease itself may lead to pulmonary hypeension. 