Help with homework?! (Science - Sound)

[geminii]

Hey guys,
I need some help with my homework which is due first day back from holidays, so these are the questions I need to answer:
1. What part of the ear allows air to move between the middle ear and the mouth and nose?
2. Provide a simple description of this structure.
Thanks heaps guys!!  Just helping with this question is ok, I know that asking other people straight out for the answers isn't right 

[slothpomba]

Perhaps make an attempt and we will tell you what is wrong or right.

[geminii]

Hmmm.... I think I saw somewhere that its the Eustachian tube? 

[Hannibal]

Hmmm.... I think I saw somewhere that its the Eustachian tube? 

I think that's right, here's a description:

The eustachian tube is a small tube that connects the middle ear to the airway in the back of the nose (nasopharynx). This tube allows outside air to enter the middle ear (behind the eardrum). The eustachian tube, which opens when a person swallows, helps maintain equal air pressure on both sides of the eardrum and prevents fluid from accumulating in the middle ear. If air pressure is not equal, the eardrum may bulge or retract, which can be uncomfortable and distort hearing. Swallowing or voluntary "popping" of the ears can relieve pressure on the eardrum caused by sudden changes in air pressure, as often occurs when flying in an airplane. The eustachian tube's connection with the middle ear explains why upper respiratory infections (such as the common cold), which inflame and block the eustachian tube, can lead to middle ear infections or changes in middle ear pressure, resulting in pain.

Source: http://www.merckmanuals.com/home/ear_nose_and_throat_disorders/biology_of_the_ears_nose_and_throat/ears.html

[geminii]

Wow, thanks heaps Hannibal!!