What are brochial tubes?

Bronchial tubes are passages that conduct air to and from the lungs. They are lined with ciliated mucous membrane and supported by cartilaginous rings. The largest bronchial tube is the trachea. It extends from the larynx (voice box) to the upper part of the chest cavity, here it divides into two chief bronchi, one leading to each lung. The bronchi divide into smaller branches called bronchioles. The smallest bronchioles, known as terminal bronchioles, lead to the air sacs (alveoli).