Final answer:
During the pharyngeal stage of swallowing, there is a risk of food entering respiratory pathways. This risk is blocked by the rise of the soft palate and uvula, and the folding of the epiglottis, which prevent access to the trachea and bronchi. If food does enter the trachea, coughing usually forces it back into the pharynx.
Step-by-step explanation:
During the swallowing process, there is a risk of food entering the respiratory pathways at the stage known as the pharyngeal stage. However, this risk is blocked by the reflexive rise of the soft palate and uvula, which close off the entrance to the nasopharynx, and the folding of the epiglottis, which covers the glottis (the opening to the larynx). These actions effectively prevent food from entering the trachea and bronchi. If food does enter the trachea, the immediate reaction is to cough, which usually forces the food up and out of the trachea and back into the pharynx.