The conducting zone of the respiratory system is made up of the nose, pharynx, larynx, trachea, bronchi, bronchioles, and terminal bronchioles; their function is to filter, warm, and moisten air and conduct it into the lungs. It consists of a series of interconnecting cavities and tubes both outside and within the lungs. It is composed of the 1st through the 16th division of the respiratory tract (airway).