What is the function of the Eustachian tube?

• A. Equalizes pressure between the middle ear and the outside environment
• B. Transmits sound from the eardrum to the inner ear
• C. Produces earwax
• D. Carries nerve signals to the brain

Answer: (A)

The Eustachian tube functions to equalize pressure between the middle ear and the outside environment. It connects the middle ear to the upper throat and is normally closed, opening briefly when you swallow, yawn, or chew. When it opens, air can flow in or out, balancing the pressure on both sides of the eardrum, which helps maintain comfortable hearing especially during altitude changes or rapid pressure shifts. Sound transmission, by contrast, is handled by the eardrum and the small bones in the middle ear; earwax is produced in the external ear canal; and nerve signals to the brain are carried by the auditory nerve, not the Eustachian tube.