Mouth/Pharynx
The pharynx is most commonly known as the throat. this is the passage that allows both food and air to pass to their designated locations. The two get separated later on in the larynx. The air passes through the nose, and the food passes through the mouth. The nasal cavity narrows into the naso-pahrynx, the part of the pharynx that is closer to the nose, and the oral cavity narrows to the oro-pharynx. Both combine later on into the hypo pharynx which then proceeds to become the larynx. The pharynx mainly only acts as a passage way, and does not have any other significant jobs, covered by smooth skin such as the type that covers the inside of your mouth.