The outer ear collects sounds from the environment and funnels them through the auditory system. The outer ear is composed of three parts, the pinna (or auricle), theexternal auditory canal (or external auditory meatus), and the tympanic membrane (or eardrum).
The outer 1/3 portion of the canal is lined with a membrane containing ceruminous (ear wax producing) cellsand hair cells. The purpose of the cerumen andhairs is to protect the eardrum
which lies at the end of the canal) by trapping dirt and foreign bodies and keeping the canal moist.
The humantympanic membrane or eardrum is a thin, concave membrane stretchedacross the inner end of the external auditory canal much like the skin covering the top of a drum.
The middle ear transmits sound fromthe outer ear to the inner ear. The middle ear consists of an oval, air-filled space approximately 2 cubic cm in volume. The middle ear can be thought of as a room, the outer wall of which containsthe tympanic membrane.
Themiddle ear is lined entirely with mucous membrane (similar to the nose) and is surrounded by the bones of the skull.
The eustachian tube connects the middle ear to thenasopharynx. This tube isnormally closed, opening only as a result of muscle movement during yawning,sneezing, or swallowing
The most noticeable example of eustachian tube function occurs when thereis a quick change in altitude, such as when a plane takes off.
The inner ear is responsible for interpreting and transmitting sound (auditory) sensations and balance (vestibular) sensations to thebrain. The inner earis small (about the size of a pea) and complex in shape; its series of winding interconnected chambers has been compared to (and called) a labyrinth. Themain components of the...