The Ear Flashcards
The ear is associated with what bone?
Temporal bone
2 special sensory functions of the ear?
Hearing and balance
The middle ear is connected to the nasopharynx by the ______
eustachian tube
Function of the external ear?
Collects soundwaves and directs it towards the middle ear
Function of the middle ear?
Conducts and amplifies vibrations towards the inner ear
Function of the inner ear?
Converts the vibration or movement of fluid into action potentials
The external ear is composed of what 2 things?
The external acoustic meatus (ear canal) and the pinna/ auricle
The pinna is formed by _____1____ and attached to the ___2_____ It is ___3____
1) elastic cartilage
2) temporal bone
3) avascular and gains nutrients from the skin
The external acoustic meatus lateral 1/3 is formed by ___1___ and the medial 2/3 by the ____2___ The medial end is marked by the ___3____ It is lined with skin which by produces ear wax by the ____4______
1) cartilage
2 petrous part of temporal bone
3) tympanic membrane
4) ceruminous glands
Define the tympanic cavity?
narrow air filled chamber in the petrous portion of the temporal bone containing the apparatus for the middle ear
Describe the two parts of the tympanic cavity?
The tympanic cavity proper (space directly internal to the tympanic membrane)
The epitympanic recess (space superior to the membrane)
What is the function of the eustachian tube? What is the structure and how does it do this?
Equalise pressure between the middle ear and nasopharynx
Close to the ear there is an osseous portion, the cartilaginous portion is near the nasopharynx and this is typically closed only becoming patent during muscular contraction which allows it to equalise the pressure
The opening of the eustachian tube is ________
anterior to the torus tobarius
The mucosa of the middle ear is ______ with the nasal cavity through the eustachian tube
continuous
The glossopharyngeal nerve provides sensory innervation to the mucosa of?
middle ear cavity, eustachian tubes, nasopharynx, oropharynx, palatine tonsils.
Why can tonsillitis cause earache and earache cause throat pain?
The glossopharyngeal nerve provides sensory innervation to both areas and due to eustachian tube the lining is continuous
What are the content of the tympanic cavity?
auditory ossicles stapedius muscle tensor tympani muscle chordates tympani Tympanic plexus of nerves
The auditory ossicles provide a mobile chain of small bones across the tympanic cavity from the ______
tympanic membrane to oval window (opening into the inner ear)
The auditory ossicles are the first bones to _______
ossify during development and are essentially mature at birth
3 auditory ossicles from lateral to medial?
Malleus, Incus and stapes
What is the smallest bone in the body?
stapes
Joints between the auditory ossicles are?
Synovial
What are the two muscles associated with the auditory ossicles?
Tensor tympani and stapedius
Tensor tympani dampens sounds by _________ It is innervated by_________
reducing vibrations of the tympanic membrane- reduces noise from chewing
CNV3
Stapedius reduces sounds by _________ It is innervated by_________
reducing vibrations of stapes on oval window
CNV7
What does the inner ear consist of?
Membranous labyrinth containing endolymph which is suspended within the perilymph filled bony labyrinth. The bony labyrinth is contained within the otic capsule of the petrous part of the temporal bone and the otic capsule is made from bone denser than the rest of the petrous temporal bone.
Describe the cochlea?
The shell shaped part of the bony labyrinth that contains the cochlear duct and is concerned with hearing
Describe the 2 functional divisions of the membranous labyrinth?
1) Vestibular labyrinth for balance contains the utricle and saccule with the 3 semicircular ducts
2) cochlear labyrinth for hearing is composed of cochlear duct occupying the spiral canal of the cochlea
The external ear is lined with ___1___
The middle ear is lined with ___2_____
1) epidermis
2) columnar mucosa
The middle ear communicates with the ____1______ superiorly and the ____2_____ medially connects ______3______
1) mastoid air cells
2) Eustachian tube
3) middle ear to nasopharynx
