Question

State the main function of the Eustachian tube.

Answer 1

The eustachian tube is also known as the auditory tube. In the adult human, the eustachian tube is about 35 mm in length and about 3 mm in diameter.

Complete step-by-step answer:
The eustachian tube is the tube that connects the nasopharynx to the middle ear which is a part of the eustachian tube. The eustachian tube is the canal whose function is to maintain the equal pressure at both the sides of the tympanic membrane. It expands from the anterior wall of the middle ear to the lateral wall of the nasopharynx almost at the level of the inferior nasal concha. It contains bony and the cartilaginous parts. The bony part which is nearest to the middle ear is made up of bone and is about 12 mm long. It starts in the anterior wall of the tympanic cavity and the tympanic cavity is connected by the internal ear cavity by two apertures. The cartilaginous part is made up of a triangular plate of elastic fibrocartilage and is about 24 mm in length.
The eustachian tube starts from the dorsal part of the pharyngeal pouch and the second endodermal pouch. It helps in the alternation of the sound waves. The eustachian tube helps to drain the mucus from the middle ear. The inflammation of the middle ear generally affects the Eustachian tube.

Note: In the case of a horse the eustachian tube is known as the guttural pouch. It is named after the Italian anatomist Bartolomeo Eustachi.