The upper lip is the part of the mouth located above the lower lip. It plays a crucial role in facial expressions, speech, and eating. The upper lip is made up of skin, muscle, and connective tissue, allowing it to move and form different shapes. This lip is also important for the formation of sounds during speech, as it helps in articulating certain letters. Additionally, the upper lip contains sensory nerves that contribute to the sense of touch and taste, enhancing the overall experience of eating and drinking.