Mod 3: Outer Ear

Auricle

The outermost, visible part of the ear

 The auricle is made

entirely of cartilage

The outer ear, or auricle, is also known as the

pinna

Function of auricle

Gather sound waves from the environment

How many layers is the human tympanic membrane is composed of

3

The point of maximum retraction of the tympanic membrane is the

umbo

The Auricle/Pinna funnels sound into the

External Auditory Ear Canal

The Auricle/Pinna enhances delivery of

high frequency sounds relative to low frequency sounds

The Auricle/Pinna aids

localization

Where is cerumen found in

the outer portion of the external auditory Canal (EAM)

What type of glands are cerumen produced by

sebaceuous

The light reflex which may be seen when inspecting the tympanic membrane with a bright light directed down the external auditory canal is known as the

cone of light

The tympanic membrane is held in position at the end of the external auditory canal by a ring of tissue called the

tympanic annulus

Which part of the tympanic membrane comprises the greatest surface area?

pars tensa

External Auditory Canal/Meatus

extends inward at a slight upward angle

External Auditory Canal/Meatus: Outer portion

cartilaginous
- contains sebaceous glands for cerumen production
- contains hair follicles

External Auditory Canal/Meatus: Inner portion

- passes through the tympanic portion of temporal bone
- No glands or hair follicles
- tow portions meet at the osseocartiliginous junction

The External Auditory Canal protects the tympanic membrane from

foregin objects

The External Auditory Canal keeps the tympanic membrane at a

constant temperature and humidity levels

The External Auditory Canal serves a sound filter

- reduces lower frequencies
- resonator for frequencies between 2000 and 7000 Hz

Tympanic membrane

concave, dis-like structure at the end of the EAC canal (ear drum)
- constructed of three layers

The tympanic membrane marks the border between the

outer and middle ear

Malleus (largest bone of the middle ear) is imbedded into the

center of fibrous portion of tympanic membrane

the tympanic membrane is

semi transparent