Midterm anatomy

Question 1

Cartilage frame, helps funnel and localize sound, amplifies sound as it enters EAC

Answer 1

Pinna

Question 2

Concavities of Pinna

Answer 2

Concha-Tragus
Triangular fossa
Scaphoid fossa

Question 3

Convexities of Pinna

Answer 3

Helix

Antihelix

Question 4

Length of external auditory canal

Answer 4

2.5 cm

Question 5

What part of external auditory canal is cartilage?

Answer 5

Lateral 1/3

Question 6

What part of external auditory canal is bony?

Answer 6

Medial 2/3

Question 7

Skin of external auditory canal

Answer 7

Cartilaginous portion- hair follicles, sebaceous glands, and ceruminous glands
Bony- thinner with no other structures

Question 8

Neural innervation of external auditory canal

Answer 8

Trigeminal nerve
Greater auriculnar nerve
Auricular branch of Vegus
Facial nerve & chordo tympani

Question 9

Tympanic membrane characteristics

Answer 9

Approx 9mm diameter, approx 140 degrees, attached to canal wall & malleus

Question 10

Layers of pars Tensa

Answer 10

Lateral epidermal- continuous with EAC skin
Medial mucosal
Intermedial fibrous

Question 11

Ossicular chain bones

Answer 11

Malleus
Incus
Stapes

Question 12

Parts of malleus

Answer 12

Manubrium-attaches to TM at umbo due to encircling by pars propria
Head & neck
Lateral process-adheres to pars propria of TM
Anterior process

Question 13

Parts of incus

Answer 13

Body- articulates with head of malleus
Short process- anchors to posterior ligament
Long process- parallels manubrium
Lenticular process- articulates with stapes

Question 14

Parts of stapes

Answer 14

Head- attaches to incus
Footplate- attaches to oval window by the annular ligament
2 crura- support the footplate to head

Question 15

Middle ear tegmen

Answer 15

Serves as roof & floor to middle cranial fossa

Question 16

Floor of middle ear contains

Answer 16

Jugular bulb & root of styloid process

Question 17

Anterior part of middle ear contains

Answer 17

Internal carotid, ET orifice, tensor tympani

Question 18

Posterior part of middle ear contains

Answer 18

Pyramidal eminence (Stapedius tendon)

Question 19

Medial part of middle ear contains

Answer 19

Sinus tympani, oval & round window niches

Question 20

Eustacian tube

Answer 20

Mucosal lined tube for ventilation of the ME

Question 21

Composition of ET

Answer 21

Cartilaginous portion- anteromedial 2/3

Bony portion- lateral 1/3

Question 22

Oval window

Answer 22

Membrane covering entry to cochlea

Question 23

Areal ratio

Answer 23

With area of TM larger than that of the oval window there is at least a 20:1 ratio of pressure amplification

Question 24

Transduction in audition

Answer 24

Sound pressure–> mechanical pressure–> hydromechanical pressure –> generation of electrical potential

Question 25

Scala vasculara of organ of Corti

Answer 25

Provides nutrition

Question 26

How the organ of Corti works

Answer 26

Reissner s membrane moves and displaces fluid

Question 27

What are the 2 types of hair cells

Answer 27

Type 1 is globular, IHC | Type 2 is cylindrical, OHC

Question 28

What are the 2 types of afferents

Answer 28

1. Thicker, mylinated, IHC | 2. Thinner, unmylinated, OHC

Question 29

Connections that join the HCs

Answer 29

Cross row, between row, tip links

Question 30

Type 1 afferents

Answer 30

``` Make up 95% of auditory system Multiple neurons innervate single HC Mylinated Thickens after it leaves habenula perforata Dendrites thin as they approach soma ```

Question 31

Small opening in the spiral lamina throug which dendrites of primary auditory system pass

Answer 31

Habenula perforata

Question 32

Type 2 afferents

Answer 32

``` Make up 5% of auditory system Single neuron innervates multiple HCs Most innervate first row of OHCs Unmylinated Thickens as it leaves habenula perforata Dendrites thicken as they approach soma ```

Question 33

Tonotopic arrangement

Answer 33

The basilar membrane is arranged from HF to LF, narrow and thinner to wider and thicker

Question 34

Movement of basilar membrane

Answer 34

Envelope- traveling wave

Question 35

Ascending auditory pathway

Answer 35

``` C SLIM C Cochlea Superior Olivary complex Lateral Lemniscus Inferior Colliculus Medial Geniculate body Auditory cortex ```