slide1 n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Auditory System PowerPoint Presentation
Download Presentation
Auditory System

Loading in 2 Seconds...

play fullscreen
1 / 53

Auditory System - PowerPoint PPT Presentation


  • 419 Views
  • Uploaded on

Auditory System. Auditory System. Adequate Stimulus for the auditory system is sound. What is sound? Two components of sound displacement component movement of molecules pressure component alternating compression and rarefaction. Human ears are sensitive only to the

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Auditory System' - cadence


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide2

Auditory System

Adequate Stimulus for the

auditory system is sound

What is sound?

Two components of sound

displacement component

movement of molecules

pressure component

alternating compression and rarefaction

Human ears are sensitive only to the

pressure component, and only between

20 Hz and 20 kHz

sound
Sound

Animation courtesy of Dr. Dan Russell, Kettering University

sound1
Sound

Animation courtesy of Dr. Dan Russell, Kettering University

slide6

Outer ear

Pinna or auricle

Auditory canal or ear canal

Tympanic membrane or eardrum

Middle ear

Ossicles

Malleus or hammer

Incus or anvil

Stapes or stirrup

slide9

http://www.youtube.com/watch?v=dyenMluFaUw&feature=player_detailpagehttp://www.youtube.com/watch?v=dyenMluFaUw&feature=player_detailpage

slide10

Latex-filled cochlea. Scala tympani and scala

vestibuli shown in red; scala media in dark blue.

Scala tympani and scala vestibuli are filled with perilymph; scala media is filled with endolymph.

slide11

Viewed in cross section, the cochlea contains three small parallel chambers. These chambers, the scalae, are separated by Reissner’s membrane and the basilar membrane. The organ of Corti contains the auditory receptors; it sits upon the basilar membrane and is covered by the tectorial membrane.

slide13

a.k.a. cochlear ganglion

a.k.a. cochlear ganglion

The spiral ganglion so named because the cell bodies follow the spiral path of the bony cochlea around the modiolus.

It is also known as the cochlear ganglion.

slide15

http://www.youtube.com/watch?v=1VmwHiRTdVc&feature=player_detailpagehttp://www.youtube.com/watch?v=1VmwHiRTdVc&feature=player_detailpage

slide17

Na+

Na+

K+

Na+

slide19

http://www.youtube.com/watch?v=1JE8WduJKV4&feature=player_detailpagehttp://www.youtube.com/watch?v=1JE8WduJKV4&feature=player_detailpage

slide21

Place theory: Pitch perception based on PLACE of greatest displacement of basilar membrane and thus, WHICH spiral ganglion cells are most active.

Rate theory: Pitch perception based on the

RATE of action potentials in spiral ganglion cells.

slide26

Speed of sound ~ 335 m/sec, Interaural distance (I.D) ~ .2 m

Therefore, maximum difference in time of arrival at the two ears is

.2 m/335 m/sec, or about 6 msec.

slide28

Because shadows are cast only when

wavelength is less than the size of the object

casting the shadow, intensity differences are

useful when wavelengths are less than

the I.D. (~.2 m; frequency greater than

~ 1,700 Hz).

Differences in time of arrival at the two ears

Is unambiguous only when wavelengths are

greater than 1/2 the I.D. (~.1 m; frequency less

than about 3,400 Hz).

slide34

http://www.youtube.com/watch?v=dyenMluFaUw&feature=player_detailpagehttp://www.youtube.com/watch?v=dyenMluFaUw&feature=player_detailpage

slide37

Summary of

Sound Localization

Three mechanisms:

1. Intensity differences: high frequencies

2. Interaural delay: sudden onset

and low frequencies

3. Spectral cues: effect of reflection by pinna

on sound spectrum

Because sounds are complex, consisting of

many frequencies, all three mechanisms are

typically used simultaneously.

slide39

Estimating Distance

to a Sound Source

1. Sound intensity

Spherical spreading of sound energy

2. Spectral properties

Atmospheric attenuation of high frequencies

3. Echoes

Greater number of echoes with distance

slide42

Speech Sounds

Hz

250 500 1000 2000 3000 4000 6000 8000

f

th

p h

s

k

ch

sh

dB

slide44

http://www.sumanasinc.com/webcontent/animations/content/vestibular.htmlhttp://www.sumanasinc.com/webcontent/animations/content/vestibular.html

slide50

The macula of the utricle is oriented horizontally.

The macula of the saccule is oriented vertically.

slide53

Vestibular Pathways

  • and their Functions
  • vestibular nuclei to cerebellum
  • posture, equilibrium
  • vestibular nuclei to nuclei of CN III, IV & VI
  • (short, fast disynaptic pathway)
  • vestibular nystagmus
  • capable of adaptation (plasticity)
  • vestibulospinal tract
  • resting postural muscle tone
  • postural reflexes
  • vestibular nuclei to nucleus of CN XI
    • righting reflex, tonic neck reflexes