Ear 2 Flashcards
Name the muscle
Tensor tympani
What is the action of tensor tympani?
Tense tympanic membrane
What is the nerve supply of tensor tympani?
CNV3
What is the insertion of tensor tympani?
Handle of malleus
What is the origin of tensor tympani?
Wall of auditory tube
What muscle is shown
Stapedius
What is the origin of stapedius?
Pyramid of middle ear
What is the insertion of stapedius?
Neck of stapes
What is the action of stapedius?
Pull footplate of stapes laterally
What is the innervation to stapedius?
CNVII
What is the combined action of stapedius and tensor tympani?
Reduce vibration passing to delicate inner ear
What is the sensory nerve supply to the tympanic cavity?
CNIX
What is the blood supply to the tympanic cavity?
Tympanic branches of posterior Auricular and maxillary arteries
Where does the lymph drain from the tympanic cavity?
Retropharyngeal nodes
A = auditory tube
B = lateral wall
C = medial wall
What does the auditory tube connect?
Nasopharynx with the tympanic cavity (middle ear)
What is the lateral part of the auditory tube?
Bony canal lined with mucosa
What is the medial part of the auditory tube?
Cartilaginous and membranous
When is the auditory tube open?
She tensor tympani contracts (swallow, yawn etc) lumen opens
Describe the pathway of the chords tympani nerve?
Arises from facial nerve
Passes to posterior wall of tympanic cavity (middle ear)
Crosses medial surface of tympanic membrane and handle of malleus
Leaves tympanic cavity via petrotympanic fissure in skull
What fissure does the chorda tympani leave the tympanic cavity?
Via petrotympanic fissure in skull
What nerve does chorda tympani join?
Lingual to the tongue
Apart from the tongue, what does chorda tympani supply?
The sublingual and submandibular salivary glands
Parasympathetic secretomotor fibres
What are the 2 parts of the labrynth?
Bony
Membranous
What lies within the body labyrinth?
Membranous labryinth
What is the body labryinth?
It is the bone which the cochlea lies, it has the same shape which allows the cochlea to fit nicely
What is perilymph?
Fluid on the inside of the bony labryinth
Conveys the energy that comes through the oval window
Name the parts of the bony labryinth
Where does the perilymph enter and where does it go out of the bony labryinth?
In through the oval window
Out through the round window
What is the fluid around the bone called compared to inside the bone?
Inside the membrane, endolymph
Between the bone and membrane perilymph
What contains the receptors which pick up the vibrations?
Saccules
What is the role of the maculae?
Respond to pull of gravity and report on changes of head position
Semicircular canals
What do the bony chambers of the cochlea turn around?
Modiolus
What do the modiolus contain?
Blood vessels and cochlear branches of CNVIII
What is this?
Cross section of cochlear
3 chambers
What is in each chamber of the cochlea?
Fluid, convey energy to the nerves etc
Name the 3 chambers in the cochlea
What is the important organ that picks up the sound in the cochlea?
How does the cochlea conduct signals?
