Anatomy Of Ear Flashcards
(18 cards)
What is the sound transmission pathway?
Sound enters outer ear → EAM → Tympanic membrane → Ossicles → Oval window → Cochlear fluids → Hair cells → Cochlear nerve (CN VIII).
What are the components of the outer ear?
- External Auditory Meatus
- Tragus
- Lobule
- Concha
What is the function of the external auditory meatus?
Conducts sound to tympanic membrane.
What are the parts of the external auditory meatus?
- Outer 1/3 (cartilage)
- Inner 2/3 (bony)
What is the role of the tympanic membrane?
Converts sound waves to mechanical vibrations.
What does the middle ear consist of?
Air-filled cavity with openings to Eustachian tube, inner ear, and mastoid air cells.
What are the ear ossicles?
- Malleus
- Incus
- Stapes
What is the function of the ear ossicles?
Transmit/amplify vibrations to the oval window.
What is the difference between adult and children’s auditory (Eustachian) tube?
Adults: longer/vertical; Children: shorter/horizontal.
What is the function of the auditory (Eustachian) tube?
Equalizes middle ear pressure.
What does the bony labyrinth include?
- Cochlea
- Vestibule
- Semicircular canals
What fluid fills the bony labyrinth?
Perilymph.
What are the inner ear fluids?
- Perilymph
- Endolymph
What is the significance of endolymph?
High K+, important for hair cells.
What are the two branches of the cranial nerve VIII?
- Cochlear branch (hearing)
- Vestibular branch (balance)
What are the parts of the cochlear structures?
- Scala vestibuli (upper)
- Cochlear duct (middle)
- Scala tympani (lower)
- Basilar membrane
- Organ of Corti
- Hair cells
- Reissner’s & Tectorial membranes
What is the mechanism of vibration in the cochlea?
Fluid vibrations move basilar membrane → Hair cells bend → Electrical signal → CN VIII.
What are the characteristics of sound waves?
- Frequency = pitch
- Amplitude = loudness
