BMS129 Lecture Notes - Lecture 11: Vestibular System, Inner Ear, Vestibular Nerve
NERVOUS SYSTEM
Lecture 11 - The ear, hearing and equilibrium
Recommended readings: CH 16 pp 592-605
1. Identify the properties of sound waves that account for pitch and loudness
2. Identify & describe the anatomy of the outer ear
3. Identify & describe the anatomy of the middle ear
4. Describe the tympanic reflex & explain its significance
5. Identify & describe the anatomy of the inner ear
6. Explain how the ear converts vibrations to nerve signals & distinguishes
differences in pitch
7. Describe the innervation of the inner ear & its projection pathways
8. Describe how the vestibular apparatus informs the brain on body position and
movement
9. Describe the projection pathways for equilibrium
Identify the properties of sound waves that account for pitch and loudness
- Sounds are audible variations in air pressure
- Pitch related to frequency
- hearing range is 20 (low pitch) - 20,000 Hz (cycles/sec)
speech is 1500-4000 where hearing is most sensitive
- Amplitude related to loudness
Identify & describe the anatomy of the outer ear
1. Pinna funnels air vibrations down external auditory meatus into
2. Auditory canal and onto the eardrum (cartilaginous and bony, S-shaped tunnel
ending at tympanic membrane (eardrum)
Ceruminous and sebaceous gland secretions that when mixed with dead cells form
cerumen (earwax)
Identify & describe the anatomy of the middle ear
Air-filled tympanic cavity in temporal bone between tympanic membrane and oval
window
1. Eustachian tube which connects middle ear to nasopharynx and which equalizes
air pressure on tympanic membrane
2. Ear ossicles: malleus, incus, stapes
3. Stapedius and tensor tympani muscles which attach to stapes and malleus
Document Summary
Lecture 11 - the ear, hearing and equilibrium. Identify & describe the anatomy of the outer ear. Identify & describe the anatomy of the middle ear: describe the tympanic reflex & explain its significance. Identify the properties of sound waves that account for pitch and loudness. Sounds are audible variations in air pressure. Pitch related to frequency hearing range is 20 (low pitch) - 20,000 hz (cycles/sec) speech is 1500-4000 where hearing is most sensitive. Identify & describe the anatomy of the outer ear: pinna funnels air vibrations down external auditory meatus into, auditory canal and onto the eardrum (cartilaginous and bony, s-shaped tunnel ending at tympanic membrane (eardrum) Ceruminous and sebaceous gland secretions that when mixed with dead cells form cerumen (earwax) Identify & describe the anatomy of the middle ear. Describe the tympanic reflex & explain its significance. Provide a protective function from loud but slowly building sounds like thunder.
