Final answer:
The eardrum vibrates properly when there is equal pressure on both sides, facilitating the hearing process. Imbalance in pressure, such as from a fluid buildup, can hinder the eardrum's function.
Step-by-step explanation:
The proper vibration of the eardrum is essential for hearing and occurs when the pressure is equal on both sides of the eardrum. When sound waves enter the ear canal, they strike the eardrum, causing it to vibrate. This vibration is transferred through the small bones in the middle ear to the cochlea, where nerve impulses are generated. However, if there is unequal pressure, such as from a fluid buildup due to infection, it can negatively affect the eardrum's ability to vibrate correctly and thus impair hearing.
The mechanisms in the ear are designed to protect against intense sounds, by reducing the force transmitted to the cochlea, thereby protecting the inner ear.