1. The Outer Ear Consists of:
The Pinna - cartilaginous, highly variable in appearance, some landmarks.
External Auditory Canal (or external auditory meatus) cm tube.

2. External Auditory Canal
lateral portion-cartilage
medial portion-osseous
lined with epidermal (skin) tissue
hairs in lateral part
cerumen (ear wax) secreted in lateral part.

3. Outer Ear Functions
Amplification / Filtering
Protection
Localization

4. The Middle Ear: A cleft within the temporal bone
Lining is mucous membrane
Tympanic Membrane separates it from EAC
Eustachian tube connects it to nasopharynx
Also Connected to Mastoid Air Cells

5. Middle Ear Structures 1- Malleus 2- Incus --Ossicles 3- Stapes
4- Tympanic Membrane (Eardrum)
5- Round Window
6- Eustachian Tube

6. Middle Ear Muscles
1. The Stapedius Attaches to Stapes,Contracts in Response to Loud sounds, chewing, speaking; Facial (VIIth cranial) nerve
2. The Tensor Tympani Helps open Eustachian tube

7. Middle Ear Functions
Impedance Matching
Filtering
Acoustic Reflex

9. INNER EAR
Two Halves:
Vestibular--transduces motion and pull of gravity
Cochlear--transduces sound energy
(Both use Hair Cells)

10. Cochlear Functions
Transduction- Converting acoustical-mechanical energy into electro-chemical energy.
Frequency Analysis-Breaking sound up into its component frequencies

11. Afferent & Efferent Neurons

12. REFERENCES www.google.com www.teachingbiology.com
web.clas.ufl.edu/users/sgriff/courses