27. What is the function described to Eustachian tube?
The eustachian tube connects the middle ear cavity with the pharynx. It helps in equalising the pressures on either sides of the ear drum. At the pharyngeal opening of the Eustachian tube, is a valve which normally remains closed.
The valve opens during yawning, swallowing and during an abrupt changein altitude, when air enters or leaves the tympanic cavity to equalise the pressure of air on the two sides of the tympanic membrane.
