7.1 Anatomy Of The Ear - need to write part3+4 Flashcards
What are the 2 functions of the ear?
Hearing
Balance
What are the 3 broad regions of the ear?
External
Middle
Inner
What is Otalgia?
Ear pain
What are signs and symptoms associated with ear disease?
Otalgia Discharge Hearing loss Tinnitus Vertigo Facial nerve palsy
What is tinnitus?
Perception of hearing sound without any external source for it
What is vertigo?
Sense of the world rotating around despite being still
Hallucination of movement
Why might patients with ear disease suffer facial nerve palsy?
As the facial nerve runs through the petrous bone, in close proximity to the middle ear.
What are the structures of the external ear?
Pinnacle
External auditory meatus
Skin lined cavity up to lateral surface of the tympanic membrane
What are the structures of the middle ear
Air filler cavity
Ossicles
Lined with respiratory epithelium
Pharyngotympanic tube
What is the boundary between structures of he external ear and structures of the middle ear?
The tympanic membrane
What is the intermittent connection from the middle ear to the nasopharynx called?
The Pharyngotympanic tube
Why is the connection between the middle ear and the nasopharynx intermittent?
Because the pharyngotympanic tube is a muscular tube that can intermittently close/open to equilibrate with atmospheric pressure within the nasopharynx
What are the 3 ossicles in the middle ear cavity?
Masseus
Incus
Stapes
What is the structure of the respiratory epithelia?
Pseudostratified columnar ciliates epithelium with goblet cells.
What are the structures of the inner ear?
Cochlea
Semicircular canals
(Both fluid filled)
What is the function of the cochlear?
To generate APs to send to the brain to receive sound
Describe the structure of the semicircular canals?
3 fluid filled semicircular structures at 90 degrees to each other
What is the function of the semicircular canals?
To generate APs that are sent to the brain to be perceived as our sense of position and balance
Why is referred Otalgia so common?
As many different nerves carry general sensation from the ear
What nerves carry GENERAL sensation from the ear?
Cervical spinal nerves (C2/C3) Vagus Trigeminal (auriculotemporal n.) Glossopharyngeal (tympanic n.) Facial nerve
What nerves carry the special sensation of hearing and balance from the ear?
Vestibulococchlear nerve ( CN XIII)
Where does the auriculotemporal nerve carry general sensory information from?
Lateral surface of the tympanic membrane
External acoustic meatus
Temporomandibular joint.
Why might pathology in the pharynx/larynx be felt in the ear?
Pain may be misinterpreted by the brain and referred to the ear as both are supplied by the glossopharyngeal nerve