The Ear Flashcards
List the structures sound waves pass through before reaching auditory receptors
0) Pina captures sound and funnels it into auditory canal
1) Auditory canal
2) Tympanic membrane
3) Ossicles
4) Oval window
5) Cochlear duct
6) Spiral organ
What is the function of the tympanic membrane?
- Transmit sound from air to ossicles in middle ear/oval window.
- Vibrates in response to percussion from compressed sound waves
What is the function of the ossicles?
- Vibrations translated into fluid waves
- Transmit & amplify vibrations of the tympanum across middle ear
What is the function of the oval & round window?
O=Connects ossicles to cochlear
R= Moves out allowing fluid movement within the cochlear
What is the function of the auditory tube? (also known as?)
- Eustachian tube
- Connects middle ear with nasopharynx
- Aerates middle ear system
- Clears mucus from middle ear into nasopharynx
What is wax made up of and what produces it?
- External auditory canal lined by skin cells
- Sebum, sloughed off skin & secretions from cerumenous glands
What is the function of the chords tympani & what nerve is it a branch of?
- Facial nerve (CN7)
- Taste innervation to anterior 2/3 of tongue
How is the nasopharynx connected to the middle ear?
Antero-inferiorly by pharyngotympanic tube
What does the tympanic membrane form the lateral wall of? What does this contain?
Air filled chamber- middle ear containing the ossicles
Why is the middle ear liable to upper respiratory tract infections?
Lined with respiratory epithelium
What & how is the middle ear connected posteriorly?
- Connected to mastoid air cells
- Through mastoid antrum/aditus of mastoid antrum
What is the nerve supply & function of tensor tympani?
Located in middle ear
N= Branch of mandibular nerve (V3)
F= Contraction pulls handle of malleus medially
What is the nerve supply & function of stapedius muscle?
Located in middle ear
N= Branch of facial nerve
F= Contraction
What fills the external & middle ear?
Air
What happens to sound in the external, middle and inner ear?
E= Sound waves enter ear M= Sound converted to mechanical movement I= Mechanical converted to electrical impusle
