The main role of the trachea is to let the air flow into the lungs. It helps in respiration. It widens and lengthens slightly as you inhale. It returns to its resting size as you exhale. The inward airflow from the trachea branches *** to the two bronchi and lungs. The cartilages ensure that the larynx and the trachea do not collapse, when there is no air in them.
