The Ear Flashcards
What is the cochlea?
The cochlea is the organ of hearing
What is the function of the saccule, utricle and semicircular ducts?
Organ of balance. Register changes in body position, especially those of the head.
What parts can the ear be divided into?
- external ear
- middle ear
- internal ear
What does the external ear consist of?
The auricle and the external acoustic meatus
What does the middle ear consist of?
The tympanic cavity, mastoid cells (air cells) and the auditory tube (eustachian tube)
What is the auditory tube?
A tube that connects the pharynx with the tympanic cavity. It is lined by ciliated epithelium.
The tendon if what muscle is attached to the manubrium of the malleus?
Tensor tympani muscle
What is the role of the auditory tube?
Communication with the pharynx.
Exchange of air and equilibrium of pressure in middle ear.
The opening of the auditory tube only happens when the pharyngeal muscles contract (swallowing).
What does the inner ear consist of?
Bony labyrinth which contains the membranous labyrinth and the internal acoustic meatus.
What kind of cartilage is the auricle?
Elastic cartilage
What kind of glands lie beneath the epidermis of the external auditory canal?
Ceruminous glands
What is the covering of the tympanic membrane externally and internally?
Externally: skin
Internally: mucosa
What is the nerve supply of the outer ear?
- Auriculotemporal nerve, which branches of the mandibular division of the trigeminal nerve (anterior)
- Facial nerve (posteriorly)
- Vagus and glossopharyngeal
What is the blood supply of the outer ear?
External carotid artery:
- anterior and posterior auricular branches.
Through which openings does the middle ear communicate with the internal ear?
Oval window (vestibular window) and round window (cochlear window)
What are the mastoid air cells?
Air-containing cavities lined with mucosa in the superior portion of the tympanic cavity. They form a system of chambers that penetrate the entire mastoid bone.
What are the auditory ossicles?
The ear bones that together with the eardrum form the sound-conducting apparatus. They are the malleus, incus and stapes
Which auditory bone is attached to the tympanic membrane?
The malleus by its manubrium.
Which ear bone is in contact with the vestibular window?
The footplate of the stapes
What closes the vestibular window?
The footplate of the stapes
How does the auditory ossicles transmit sound?
They transmit the vibrations of the tympanic membrane. The footplate of the stapes transmits the vibrations to the fluid of the inner ear.
Which muscles control the tension of the bones in the tympanic cavity?
Tensor tympani and stapedius
What is the promontory of the tympanic cavity?
The cochlea bulging into the tympanic cavity
What nerve plexus lies above the promontory in the tympanic cavity?
Tympanic plexus, formed by the tympanic nerve of the glossopharyngeal nerve and sympathetic fibers of the carotid plexus from the internal carotid artery.
In which wall of the tympanic cavity are the oval and round windows?
Medial wall
What closes the cochlear window?
Secondary tympanic membrane
In which wall of the tympanic cavity does the facial canal run?
Posterior
In which wall of the tympanic cavity can you find the lateral semicircular canal?
Posterior
In which canal lies the tensor tympani muscle?
In the semicanal of the tensor tympani muscle.
What does the musculotubal canal consist of?
Semicanal of tensor tympani muscle and semicanal of auditory tube with the bony septum between them.
Which wall of the tympanic cavity is the jugular wall?
The floor of the cavity. The jugular vein lies beneath it.
Which wall of the tympanic cavity is the carotid wall?
Medial wall
What is the insertion and origin of the tensor tympani muscle?
It originates from the cartilaginous wall of the semicanal of the tensor tympani muscle and it inserts on the manubrium of the malleus.
What is the action of the tensor tympani?
The tensor tympani muscle pulls the eardrum inward and pushes the footplate of the stapes into the vestibular window, thus increasing the sensitivity of transmission.
Which nerve innervates the tensor tympani muscle?
Tensor tympani nerve of the mandibular division of the trigeminal nerve.
What is the origin and insertion of the stapedius?
The stapedius originates in a bony canal that communicates with the facial canal. Its tendon inserts on the stapes.
What is the action of the stapedius?
The stapedius muscle levers the footplate of the stapedius out of the vestibular window, which dampens transmission.
Which nerve innervates the stapedius muscle?
Facial nerve by the stapedius nerve
What is the content of the osseous labyrinth and what is the content of the membranous labyrinth?
Osseous labyrinth: perilymph
Membranous labyrinth: endolymph
The perilymphatic duct lets the osseous labyrinth communicates with what?
The subarachnoid space
What does the vestibular window lead into from the tympanic cavity?
The vestibule of the ear.
What are the two parts of the vestibule?
The saccule and the utricle.
In which parts of the saccule and the utricle can you find sensory epithelium?
In the macula of the saccule and the macula of the utricle.
The perilymphatic spaces above and below the membranous parts of the cochlea are called what?
Scala vestibuli (above) and scala tympani (below)
Each semicircular duct have a membranous ampulla that contains what kind of epithelium?
Sensory epithelium, the ampullary crest
