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ppt of Sensory organ


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ppt of Sensory organ

  1. 1. By – Mr. ASHOK BISHNOI Lecturer, JINR
  3. 3. Divided into “3” parts:- 1. Outer Ear 2. Middle Ear (Tympanic cavity) 3. Inner Ear
  4. 4. Major Divisions of the Ear Peripheral Mechanism Central Mechanism Outer Ear Middle Ear Inner Ear VIII Cranial Nerve Brain
  5. 5.  It consist of the auricle (Pinna) & External acoustic meatus ( Auditory canal)
  6. 6. Pinna Landmarks  Helix  Antihelix  Concha  Tragus  Intertragal Notch  Antitragus
  7. 7. Auricle (Pinna):-  It is visible part of ear  It composed of fibro elastic cartilage convered with skin.  Helix- it is outer ridge part  Lobule (Ear lobe) –Soft pliable part
  8. 8. External acoustic meatus ( Auditory canal)  Slightly “S” Shaped tube  About 2.5 cm long ( 1 inch )  External from auricle to tympanic membrane  There numerous ceruminous gland & hair follicles  Numerous gland are modified sweat gland that secret cerumen (Earwax)
  9. 9. Tympanic membrane (Eardrum):-  Thin membrane  It is Oval shaped  Forms boundary between outer and middle ear  Vibrates in response to sound waves  Changes acoustical energy into mechanical
  10. 10. Mastoid Process of Temporal Bone  Bony ridge behind the auricle.  Hardest bone in body, protects cochlea and vestibular system.  Provides support to the external ear and posterior wall of the middle ear cavity.  Contains air cavities which can be reservoir for infection
  11. 11.  Collect sound  Localization  Resonator  Protection  Sensitive (earlobe)
  12. 12. This is irregular shaped air filled cavity. 1- Malleus 2- Incus 3- Stapes 6- Eustachian Tube
  13. 13. The Ossicles  Ossicular chain = malleus, incus & stapes  Malleus (It is Hammer shaped bone)  TM attaches  Incus (It is Anvil shaped bone)  Connector function  Stapes ( It is a Stirrup shaped bone)  Smallest bone in the body  Footplate inserts in oval window on medial wall Focus/amplify vibration of TM to smaller area, enables vibration of cochlear fluids
  14. 14. Eustachian Tube (Pharyngotympanic tube) ( “The Equalizer”)  Mucous-lined, connects middle ear cavity to nasopharynx  “Equalizes” air pressure in middle ear  Normally closed, opens under certain conditions  Closing of the Eustachian tube protects the middle ear from unwanted pressure fluctuations and loud sounds.
  15. 15.  Conduction  Conduct sound from the outer ear to the inner ear  Protection  Creates a barrier that protects the middle and inner areas from foreign objects  Transducer  Converts acoustic energy to mechanical energy  Converts mechanical energy to hydraulic energy  Amplifier  Transformer action of the middle ear
  16. 16.  The inner ear contain the organ of hearing & balance  It consist of –  Vestibule (Balance)  Cochlea  Semicircular canal Cochlea - Snail-shaped organ with a series of fluid-filled tunnels; converts mechanical energy into electrical energy
  17. 17. 22 Oval Window – located at the footplate of the stapes; when the footplate vibrates, the cochlear fluid is set into motion Round Window – functions as the pressure relief port for the fluid set into motion initially by the movement of the stapes in the oval window
  18. 18. 23 Organ of Corti  The end organ of hearing; contains stereocilia and hair cells.
  19. 19.  Convert mechanical sound waves to neural impulses that can be recognized by the brain for:  Hearing  Balance
  20. 20. Pathway of Sound:-  Sound waves enter pinna travel through auditory canal  Sound waves strike tympanic membrane causing vibrations (mechanical energy)  Vibrating TM causes ossicles to vibrate  Vibrating stapes bone at oval window generates movement of cochlear fluid (Hydralics)  Fluid movement stimulates cilia- lined cochlea  Cilia sends electrical impulses along auditory nerve to brain for interpretation
  21. 21. Flow of ear:-
  22. 22.  Hearing  Sound Conduction and Transmission  Balance and Equilibrium