Ear Flashcards
Chapter 12
What are the three anatomical regions of the ear?
- external ear
- middle ear
- internal ear
What does the external and middle ear do?
reception and transmission of the sound waves to the inner ear where the inner ear
Where does the the inner do?
where the sound waves are converted to the electrical impulses and conveyed to the brain
-also involved in balance
What are the components of the external ear?
- auricle
- external acoustic meatus
What is the auricle made of?
cartilaginous core covered in think skin
What does it do?
has some contours that aid in collecting the sound and transfer it to the external acoustics meatus
What is the lobule?
- is the inferior part of the auricle
- made of cartilage which is replaced by connective tissue
Where is the external acoustic meatus?
connects the auricle to the tympanic membrane
What is the external acoustic meatus made of?
- lateral 1/3 is cartilaginous
- medial 2/3 is bony
What are ceruminous glands?
- glands that are located on the skin of the external acoustic meatus
- modified sweat glands
- secrete cerumen
What does cerumen do?
slows the growth of microorganisms in the external acoustic meatus and reduces the risk of infection
Where is the middle ear located?
in the petrous part of the temporal bone
What are the components of the middle ear?
- three ossicles (bones)
- lined with mucus membrane that is continuous with the nasopharynx
What are the three ossicles?
- malleus
- incus
- stapes
What doe the ossicles do?
-amplify and convey the sound from the tympanic membrane to the inner ear
How are the ossicles held?
by synovial joints
What do the small skeletal muscles do? What are their names?
- tensor tympani
- stapedius
- to dampen sound
What are the walls of the tympanic cavity and what their distinct features?
- lateral wall: carries the tympanic membrane separating the middle and external ears
- medial wall: thin boney plate; separates the tympanic cavity from the inner ear and carries two openings
- anterior wall: connected to the nasopharynx via the auditory tube
- superior wall: separates the tympanic cavity from the middle cranial fossa
What are the two openings of the medial wall?
- fenestra vestibuli (oval window): covered by stapes
- fenestra cochlea (round window): covered by membrane
Where is the inner ear located?
- petrous part of the temporal bone
- includes the osseous and membranous divisions
What does the inner ear contain?
- perilymph
- bony labyrinth
- semicircular canals
- choclea
- membranous labyrinth
What is perilymph? What does it do?
- CSF like fluid
- surrounds the enclosed membranous labyrinth
What is the bony labyrinth?
-series of boney cavities divided into semicircular canals, vestibule, and cochlea
What are semicircular canals?
three tubes that open into the vestibule
