EAR

Question 1

INNER EAR

Overview

Answer 1

= Irregular system of canals and cavities
1. Openings (5)

2. OSSEUS LABYRINT (3*Perilymph-filled compartments)
   a. Semicircular canals
   b. cochlea
   c. vestibulum
   - Perilymph

3. MEMBRANA LABYRINT 
(4* endolympha filled compactments)
a- Sacculus 
b- Utricules
c- 3 semicircular ducts
d- Cochlear duct
- Endolympha

4. COCHLEA = hearing
   3 channels/scalae
   a. Scalae vestibule
   b. Scalae tympani

a+b: communicates at apex = HELICOTREMA

c. Scala media
= Cochlear duct

5. COCHLEARSYSTEM –> HEARING

6. VESTLBULAR SYSTEM --> BALANCE
Balance: Head mvmts -> flow of endolymph --+-->
Vestibular neurons
a. MACULA
b. Crista Ampullaris

7. VESTIBULARAR and COCHLEAR PATHWAY
   - N.Vestibulocochlearis
8. NUCLEI OF CRANIAL NERVES
   N.VESTIBULOCHOCHLEARIS (VIII)
   a. Nucleus vestibular is rostralis et caudales
   b. Nucleus vestibular is lateralis et medialis
   c. Nucleus Cochlearis dorsalis
   d. Nucleus Cochlearis ventralis

Question 2

INNER EAR

Openings

Answer 2

Openings (5)
1. Porus Accusticus Internus
2. Vestibular window
3. Cochlear window
(2+3= middle EAR)
4. Canalicus cochleae
5. Aqueductus vestibulii
(4+5 --> SUPRACHORIOD SPACE)

Question 3

INNER EAR

OSSEUS LABYRINTH

Answer 3

3 perilympha-filled compartments

• 3 semicircular canals
• cochlea
• vestibulum

Perilympha:
- Na+ rich
- From CSF through perilymphatic duct
    - In cochlear canalicules
Ultra filtrate from blood vessels

Question 4

INNER EAR

MEMBRANA LABYRINTH

Answer 4

4 endolympha-filled compartments

• Sacculus
• Utricules
• 3 semicircular duct
• Cochlear duct

Endolympha:
K+ rich
Ultra-filtrate that from stria vascularis
- cochlear duct

Question 5

INNER EAR

COCHLEA

Answer 5

= HEARING
3 Channels/Scalae
- scala vestibule 
- scota tympani 
Communicates at apex --> helicotrema
Scala media
- Scala media = Cochlear duct

Question 6

INNER EAR

COCHLEARSYSTEM

Answer 6

HEARING
EXTERNAL EAR
1. Soundwaves are picked up
2. Eardrum vibrates

CAVUM TYMPANI - Middle EAR
3. Air oscillation converted
in oscillation of auditatory ossicles
4. Footplate of Stapes applies pressure on vestibular window.

INNER EAR

5. Vibration reaches the perilymph of the cochlea
6. Stimulation of spiral organ by vibration of basilar membrane.
   a. Low sounds near helicotrema
   b. High sounds near base

Question 7

INNER EAR

VESTIBULAR SYSTEM,

Answer 7

BALANCE
Head movements –Flow of endolymph–> + Vestibule neurons

MACULA x2

1. Macula of utriculus
2. Macula of saccule

Responsible for sensation of:

• static position of head
• linear acceleration & deceleration

Function in STATIC equilibrium

CRISTA AMPULLARIS
- in ampullae of semicircular ducts

3 semicircular ducts I to each other
Movement of head in any plane or rotation
–>+
vestibular neurons

Function in DYNAMIC equilibrium

Question 8

INNER EAR

VESTIBULAR & COCHLEAR PATHWAX

Answer 8

N.VESTIBULO COCHLEARIS

Vestibular nerves –> majority terminate.in vestibular nuclei.
1. Nucleus vestibularis lat ( Reiter)
2. Nucl vestibularis rostralis (Bechtenew)
3. Nucl vestibulais medialis (schwalbe)
= PONS and MO

4. Nucleus vestibularis caud. (Roller) = Cerebellum

COCHLEAR Nerves –> synapse in cochlear nuclei
1. Nucl. cochleais dorsalis
2. Nucl cochlearis ventralis
= Lateral MO

Question 9

INNER EAR

Nuclei

Answer 9

N vestibulocochlearis (VIII)

• Nucl vestibularis lat et med
• Nucl vestibularis rost et caud
• Nacl cochlearis dorsalis et ventralis

Question 10

EXTERNAL EAR

Answer 10

ear = organum auditus & equilibri
–> vestibulocochlear organ.
Auris Externa!

ROLE:
- Acts as an acoustic ANTENNA
- Collects and focus sound waves –> ear canal/resonation –> Middle ear
- CHARACTERISTICS:
Highly mobile in most animals.
Size and shape varries in breed and species

Question 11

EXTERNAL EAR

Meatus accucsticus externus

Answer 11

- Attached to basal portion of concha
By annular ligament.
= Flexibility
- Sebaceous glands --> Cerumen
\+ Ceruminal

Question 12

EXTERNAL EAR

MEMBRANA TYMPANI

Answer 12

3 Layers

1. Stratum Cutaneum
   - Stratifies squamous epithelium
2. Stratum Proprium
   - Fibrous CT
3. Stratum Mucosum
   - Simple squamous epithelium

Attached to Malleus

Question 13

EXTERNAL EAR

CAVUM TYMPANI

Answer 13

Middle EAR - AURIS MEDIA
- in petrousus temporal bone
PARTS:
1. EPITYMPANICUM
- Contains 3 Ossicles
2. MESOTYMPANICUM
- Lateral wall, mb tympanii
- Eustachian Tube --> NASOPHARYNX
3. HYPOTYMPANICUM
= Bulla Tympanicum

Question 14

EXTERNAL EAR

WALLS

Answer 14

Lat= tympanic bullea mb
Med= 2 windows
- Fenestra Vestibuli: cavum tympani –> internal ear
- Foramen Cochlea: Vibration absorption
Mechanical Stimuli –> Transmitted by ossicles –> Internal ear –>Translation in nerve impulses.

Question 15

EXTERNAL EAR

OSSICULA ADDITUS

Answer 15

M. Tensa Tympani
--> N.Tensa Tympani EX. N. Mandibularis
M. Stapodieus
-> N.Stapedius EX. N. Facialis
= Fix bones
protect cochlea // loud sounds
 --> Attenuation of sound conduction. 

AUDITORY OSSICLES:

1. Anvill - STAPES
2. Hammer - MELLEUS
3. Stirrup - INCUS

Question 16

EXTERNAL EAR

STRUCTURES

Answer 16

APEX
HELIX - Elastic cartilage
CARTILAGO AURICULAE
- Margo Tragicus
- Margo Antitragicus
Spina Helicis
- Crus Helicis med
- Crus Helicis lat
Saccus cutaneus medialis
Antitragus
Intertracic notch

CONCHA
Incissura cartilaginis
Meatus accusticii
Pretracic notch
Tragus
- Lamina Tragi
Cartilago annulais
Meatus acousticus externus
Membrana timpanica

MIDDLE EAR