bronchus /brong′kəs/ pl. bronchi [L; Gk, bronchos, windpipe] , any one of several large air passages in the lungs through which pass inhaled air and exhaled air. Each bronchus has a wall consisting of three layers. The outermost is made of dense fibrous tissue, reinforced with cartilage. The middle layer is a network of smooth muscle. The innermost layer consists of ciliated mucous membrane. Also called bronchial tube. Kinds include lobar bronchus, primary bronchus, segmental bronchus. See also bronchiole. −bronchial, adj.
