CSD 3103 anatomy of speech and hearing mechanisms Hearing mechanisms Fall 2008

DownloadCSD 3103 anatomy of speech and hearing mechanisms Hearing mechanisms Fall ...

Advertisement
Download Presentation
Comments
lotus
From:
|  
(4002) |   (0) |   (0)
Views: 199 | Added: 25-10-2011
Rate Presentation: 0 0
Description:
The outer ear. Cross section of the external ear. Major structures of The outer ear. Pinna or auricleExternal auditory meatus or external ear canalTympanic membrane or eardrum. The pinna. Size and shape varies from person to personGathers sound from the environment and funnels it to the eardrumMade entirely of cartilage and covered with skin.
CSD 3103 anatomy of speech and hearing mechanisms Hearing m...

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

Download Policy: Content on the Website is provided to you AS IS for your information and personal use only and may not be sold or licensed nor shared on other sites. SlideServe reserves the right to change this policy at anytime. 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 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -




1. CSD 3103 anatomy of speech and hearing mechanisms Hearing mechanisms Fall 2008 The Outer Ear

2. Show figure 9.2--cross section of the external ear. Show figure 9.2--cross section of the external ear.

3. Major structures of The outer ear Pinna or auricle External auditory meatus or external ear canal Tympanic membrane or eardrum Structures of the outer ear include the Auricle or Pinna, the external auditory meatus or external ear canal, and for some, the tympanic membrane or ear drum. Some people consider the eardrum part of the middle ear, some consider it part of the outer ear. I think it?s the boundary between both, but we will consider it in our discussion of the outer ear. Structures of the outer ear include the Auricle or Pinna, the external auditory meatus or external ear canal, and for some, the tympanic membrane or ear drum. Some people consider the eardrum part of the middle ear, some consider it part of the outer ear. I think it?s the boundary between both, but we will consider it in our discussion of the outer ear.

4. The pinna Size and shape varies from person to person Gathers sound from the environment and funnels it to the eardrum Made entirely of cartilage and covered with skin Pinna: sometimes called the auricle. Size and shape is extremely variable from person to person. It functions, somewhat poorly, as a device to gather sound from the environment and funnel to the ear. The pinna is made entirely of cartilage and is covered with skin that is continuous with the face. Pinna: sometimes called the auricle. Size and shape is extremely variable from person to person. It functions, somewhat poorly, as a device to gather sound from the environment and funnel to the ear. The pinna is made entirely of cartilage and is covered with skin that is continuous with the face.

5. The pinna Major landmarks on the pinna Fig 2-5 Major Landmarks of the Pinna Lobule or earlobe--bottom most portion of the auricle other landmarks to point out: ? Helix ? antitragus ? antihelix ? tragus--latin for ?goat?s beard?--as men age, they develop hair here which looks like a goat?s beard. Pushing against the tragus is an effective way to block the entrance of the ear canal. ? concha--divided into 2 parts cymba concha and cavum concha. Fig 2-5 Major Landmarks of the Pinna Lobule or earlobe--bottom most portion of the auricle other landmarks to point out: ? Helix ? antitragus ? antihelix ? tragus--latin for ?goat?s beard?--as men age, they develop hair here which looks like a goat?s beard. Pushing against the tragus is an effective way to block the entrance of the ear canal. ? concha--divided into 2 parts cymba concha and cavum concha.

6. The pinna Geographic landmarks for the pinna concha--divided into 2 parts cymba concha and cavum concha. Use Fig 1.1 to show these. The concha aids in the ability to localize sources of sound and to funnel the sound to the external canal. It also has some resonant effects. concha--divided into 2 parts cymba concha and cavum concha. Use Fig 1.1 to show these. The concha aids in the ability to localize sources of sound and to funnel the sound to the external canal. It also has some resonant effects.

7. Resonance properties of The pinna Resonance effects of the helix (flange) and concha in the most favorable azimuth position. The helix has a 2 dB peak at 4000 Hz. The concha has a 9 dB increase at 5300 Hz. Fig 4.2 shows resonant effect of helix (marked flange) and concha in most favorable azimuth position. The helix has a 2 dB peak at 4K. The concha has a 9 dB increase at 5300 Hz. The insert shows the pinna in the coronal view, with the flange and concha identified. The solid lines show the acoustic pressure gain in dB as a function of the stimulus frequency that results from each of these structures. The dashed line shows the gain that results from resonance in the external meatus. The solid unconnected circles show the total acoustic gain produced by the external ear. Sound source at 45 o azimuth.Fig 4.2 shows resonant effect of helix (marked flange) and concha in most favorable azimuth position. The helix has a 2 dB peak at 4K. The concha has a 9 dB increase at 5300 Hz. The insert shows the pinna in the coronal view, with the flange and concha identified. The solid lines show the acoustic pressure gain in dB as a function of the stimulus frequency that results from each of these structures. The dashed line shows the gain that results from resonance in the external meatus. The solid unconnected circles show the total acoustic gain produced by the external ear. Sound source at 45 o azimuth.

8. The pinna The pinna and its major landmarks Show fig 6-34 and review major landmarks again including ? scaphoid fossa ? triangular fossa ? crus of helix Show fig 6-34 and review major landmarks again including ? scaphoid fossa ? triangular fossa ? crus of helix

9. The external auditory canal Cross section of the external ear The External Auditory Canal: go back to fig 9.2 Cross section of the external ear The External Auditory Canal: go back to fig 9.2 Cross section of the external ear

10. The external auditory canal 2.5 cm long S-shaped Outer 1/3 is cartilaginous Inner 2/3 is bone Structures Sebaceous glands Hair follicles Osseocartilaginous junction tube formed in the side of the head, beginning at the concha and extending inward at a slight upward angle for about (2.5 cm) 1 inch in an adult. The canal is elliptical, averaging about 9 mm in height and 6.5 mm in width (adult). S-shaped pathway (protective function) and slight downward tilt Children?s canals tend to be less s-shaped and more horizontal---has implications for them The canal is lined entirely in skin. The outer portion (about 1/3 the length) passes thru cartilage. The skin in this area supports several sets of glands, including the sebaceous glands which secrete sebum, an oily fatty substance. The product of these secretions is cerumen, or earwax. Talk about the purpose of cerumen (lubrication, protection, antimicrobial), movement, and problems with aging. Hair follicles--protection. Inner 2/3 of canal is bony--passes thru the tympanic portion of the temporal bone. No glands or hair here. The cartilaginous portion and bony portion meet at the osseocartilaginous junction. The condyle (protrusion of the mandible) comes to rest right below this junction (when the jaw is closed). If bite is off, the condyle will put pressure on this junction and cause significant pain.tube formed in the side of the head, beginning at the concha and extending inward at a slight upward angle for about (2.5 cm) 1 inch in an adult. The canal is elliptical, averaging about 9 mm in height and 6.5 mm in width (adult). S-shaped pathway (protective function) and slight downward tilt Children?s canals tend to be less s-shaped and more horizontal---has implications for them The canal is lined entirely in skin. The outer portion (about 1/3 the length) passes thru cartilage. The skin in this area supports several sets of glands, including the sebaceous glands which secrete sebum, an oily fatty substance. The product of these secretions is cerumen, or earwax. Talk about the purpose of cerumen (lubrication, protection, antimicrobial), movement, and problems with aging. Hair follicles--protection. Inner 2/3 of canal is bony--passes thru the tympanic portion of the temporal bone. No glands or hair here. The cartilaginous portion and bony portion meet at the osseocartilaginous junction. The condyle (protrusion of the mandible) comes to rest right below this junction (when the jaw is closed). If bite is off, the condyle will put pressure on this junction and cause significant pain.

11. The external auditory canal Resonance effects of the external auditory meatus, shown as the ratio of the SPL at the eardrum to the SPL at the entrance of the ear canal at 0o azimuth. Resonance property of external canal--Fig 6-37 Some variability from person to person. Averages about a 15 dB increase between 3-4 k. Resonance property of external canal--Fig 6-37 Some variability from person to person. Averages about a 15 dB increase between 3-4 k.

12. The external auditory canal Combined effects of the presence of the head in a sound field. The upper solid curve represents 0o azimuth, long dashes represent 45o, and the short dashes represent a 90o azimuth. Putting the ear together---Fig 6-38. Combined effect of presence of head (pinna and external canal) in space at three different azimuths. Notice that when the sound is 90o, that shows the best advantage. Putting the ear together---Fig 6-38. Combined effect of presence of head (pinna and external canal) in space at three different azimuths. Notice that when the sound is 90o, that shows the best advantage.

13. The tympanic membrane Major landmarks of the tympanic membrane Tympanic Membrane: The external meatus ends at the TM, which is tilted at an angle of about 55o to the canal. Fig 2-8 major landmarks of the TM--looking otoscopically. The TM is firmly attached to the tympanic sulcus, a groove in the temporal bone, by a ring of fibrocartilaginous connective tissue called the tympanic annulus The eardrum is smooth and translucent. Average thickness is about 0.074 mm Concave outward rather than flat with the meatus. The dimple or peak of the concavity is called the umbo. The eardrum has four layers. The most lateral layer is continuous with the skin of the ear canal. The most medial layer is continuous with the mucous membrane of the middle ear. Sandwiched between them are two fibrous layers--which provides a lot of strength to the tm. The fibrous layers are unevenly distributed. The density is greatest towards the periphery and in the center. A small triangular area contains very few fibers, so results in rather flaccid region of the membrane. Hence referred to as pars flaccida the remainder of the eardrum is held rather tense and is known as the pars tensa. The TM is connected to the malleus, which is the first of the 3 middle ear bones at the manubrium Cone of light--define. Radiates from the umbo. Hallmark of a healthy TMTympanic Membrane: The external meatus ends at the TM, which is tilted at an angle of about 55o to the canal. Fig 2-8 major landmarks of the TM--looking otoscopically. The TM is firmly attached to the tympanic sulcus, a groove in the temporal bone, by a ring of fibrocartilaginous connective tissue called the tympanic annulus The eardrum is smooth and translucent. Average thickness is about 0.074 mm Concave outward rather than flat with the meatus. The dimple or peak of the concavity is called the umbo. The eardrum has four layers. The most lateral layer is continuous with the skin of the ear canal. The most medial layer is continuous with the mucous membrane of the middle ear. Sandwiched between them are two fibrous layers--which provides a lot of strength to the tm. The fibrous layers are unevenly distributed. The density is greatest towards the periphery and in the center. A small triangular area contains very few fibers, so results in rather flaccid region of the membrane. Hence referred to as pars flaccida the remainder of the eardrum is held rather tense and is known as the pars tensa. The TM is connected to the malleus, which is the first of the 3 middle ear bones at the manubrium Cone of light--define. Radiates from the umbo. Hallmark of a healthy TM

14. The tympanic membrane A healthy right tympanic membrane Fig 9.3 a right TM Identify major landmarks again.Fig 9.3 a right TM Identify major landmarks again.


Other Related Presentations

Copyright © 2014 SlideServe. All rights reserved | Powered By DigitalOfficePro