Week 11: Auditory Pathway Flashcards
Which bone does the ear sit around?
Temporal bone
How is the ear divided?
External ear:
receives sound waves
Middle ear:
sound waves –> mechanical waves through tympanic membrane
Inner ear:
Mechanical waves –> electrical waves
What is the function of the auricle?
to funnel sound waves into the external acoustic meatus
What structure separates the external ear from the middle ear?
tympanic membrane
What structure connects the middle ear to the nasopharynx?
via the Eustachian tube (a.k.a auditory tube)
The middle ear contains 3 ossicles. What are they called?
- Malleus
- Incus
- Stapes
What happens to the eustachian tube as we age?
it becomes more vertical (it is more horizontal in infants - this is why they are more prone to ear infections as it is easier for infection to travel)
What are the functions of the eustachian tube?
- ventilation
- drainage
- equilibriate the pressure between the external and internal environment
What are the 3 techniques to open the Eustachian tube to equilibriate pressure again?
yawn
swallow
pinch nose and blow out of cheeks
Why is the middle ear a high risk space?
- Connected to nasopharynx –> prone to infection
- Connected to mastoid air cells –> infection can spread to middle cranial fossa
- Internal jugular vein lies inferior –> risk of thrombosis
- Internal carotid artery lies anterior
- Transversed by chorda tympani and facial canal –> infection risk
What is pulsatile tinnitus?
ringing that matches your heart rate
The inner ear is composed of 2 special sense organs. What are they?
- Vestibular system
- vestibule, semi circular canals, semi circular ducts
- important for balance - Cochlear
- cochlear ducts
- important for hearing
In the cochlear, which part detects:
- Low frequency sound
- High frequency sound
- Apex of cochlea
2. Base of cochlear
What are the 2 fluid filled cavities found in the cochlea?
- Bony labyrinth (outside)
2. Membranous labyrinth (inside)
What fluid does the bony (outer) labyrinth contain?
perilymph