Intrapulmonary Air Conduits

The intrapulmonary air conduits extend from the intralobular bronchi to the terminal bronchioles and do not participate in gas exchange. Beneath their epithelia, a layer of smooth muscle surrounds these airways. Identify the cartilage plates surrounding the bronchi, and the lack of plates surrounding the bronchioles. Note the close juxtaposition of the airways with the pulmonary vessels. Observe the that the bronchiole is surrounded by alveoli.