The Ear

1. The Ear

2. The Ear

3. Pinna – funnels sounds down ear canal towards the ear drum Pinna

4. Outer Ear Pinna Outer Ear

5. Middle Ear Pinna Outer Ear Middle Ear

6. Inner Ear Pinna Outer Ear Middle Ear Inner Ear

7. Ear Canal (Auditory Canal) – directs sounds towards the ear drum Pinna Ear canal Outer Ear Middle Ear Inner Ear

8. Ear Drum (Tympanic membrane) – consists of a thin sheet of skin and muscle that vibrates with sound waves Pinna Ear Drum Ear canal Outer Ear Middle Ear Inner Ear

9. Eardrum (Tympanic membrane)

12. Hammer – attached to ear drum. Vibrates with ear drum. Hammer Pinna Ear Drum Ear canal Outer Ear Middle Ear Inner Ear

13. Anvil – jointed between hammer and stirrup. Vibrates in time with hammer. Anvil Hammer Pinna Ear Drum Ear canal Outer Ear Middle Ear Inner Ear

14. Stirrup Stirrup – picks up vibrations and passes these on to the oval window. Anvil Hammer Pinna Ear Drum Ear canal Outer Ear Middle Ear Inner Ear

15. Stirrup The three Ossicles function together to amplify the sound waves that arrive at the ear drum to about 30x. Anvil Hammer Pinna Ossicles Ear Drum Ear canal Outer Ear Middle Ear Inner Ear

16. Stirrup Oval Window – the stirrup transfers vibrations through the oval window to the fluid in the cochlea. Oval window Anvil Hammer Pinna Ossicles Ear Drum Ear canal Outer Ear Middle Ear Inner Ear

17. Stirrup Cochlea – a fluid filled tube lined with clusters of hair cells. As vibrations pass through the fluid, they trigger the hair cells. Ovalwindow Anvil Hammer Pinna Ossicles Cochlea Ear Drum Ear canal Outer Ear Middle Ear Inner Ear

18. The Organs of Corti are found on the basilar membrane which gets wider towards the tip of the cochlea. The wide end resonates with low pitch (frequencies), while the narrow end resonates with higher pitch (frequencies).

19. Hair cells:The outer hair cells help to amplify the vibration, while the inner hair cells in the Organs of Corti are involved in sound detection Organs of Corti

20. Stirrup Round window – flexible, absorbs pressure waves from fluid inside cochlea. Ovalwindow Anvil Hammer Pinna Auditory nerve Ossicles Cochlea Ear Drum Ear canal Round window Outer Ear Middle Ear Inner Ear

21. Vibrations enter the cochlea through the oval window and are absorbed by the round window at the other end. This helps to dissipate the disturbances.

22. Stirrup Eustachian tube – connects middle ear with buccal cavity – allows equalisation of pressure to alleviate pressure against the eardrum. Ovalwindow Anvil Hammer Pinna Auditory nerve Ossicles Cochlea Ear Drum Eustachian tube Ear canal Round window Outer Ear Middle Ear Inner Ear

23. Stirrup Auditory Nerve – transmits signals from the hair cells to the brain. Ovalwindow Anvil Hammer Pinna Auditory nerve Ossicles Cochlea Ear Drum Eustachian tube Ear canal Round Window Outer Ear Middle Ear Inner Ear

24. Stirrup To the brain Ovalwindow Anvil To the brain Hammer Pinna Auditory nerve Ossicles Cochlea Ear Drum Eustachian tube Ear canal Round window Outer Ear Middle Ear Inner Ear

26. Stirrup Semi-circular canals Semi-circular canals control balance. Ovalwindow Anvil To the brain Hammer Pinna Auditory nerve Ossicles Cochlea Ear Drum Eustachian tube Ear canal Round window Outer Ear Middle Ear Inner Ear

27. The Semi-circular Canals The Utricle and Saccule are sensitive to gravity and linear acceleration.

28. They are arranged at right angles to each other, so they can sense motion in 3 dimensions. Movement in the canals causes fluid to push against the cupola, triggering the hair cells.