Ear 1 Flashcards
A = external
B = middle
C = inner
What is the function of the cochlea?
Hearing (auditory)
What is the function of the semicircular canals?
Balance (vestibular)
What are the parts of the external ear?
Auricle
External auditory meatus and canal
Lateral surface of the tympanic membrane (=hearing function)
What is the tympanic membrane?
Ear drum
What is in the middle ear?
Medial surface of the tympanic membrane
Tymalnkc cavity
Ossicles
Pharyngotympanic (eustachian/auditory) tube
What are the ear ossicles?
Tiny little works that transmit the sound energy to the middle ear
What is the pharyngotympanic tube?
Hearing function
Equalisation of pressure of the middle ear and nasopharynx
From the tympanic cavity to the nasopharynx
Where is the auditory apparatus?
Inner ear
What is in the inner ear?
Vestibular apparatus (semicircular canals)
Internal auditory meatus
Vestibule cochlear nerve (CNVIII)
oval window and round window (=hearing and balance function)
What windows allow hearing and balance function and where are they found?
Oval and round windows found in the inner ear
A = ossicles
B = semicircular canals
C = cochlear
D = vestibular nerve
E = cochlear nerve
Where do the vestibular and cochlear nerves go through?
Internal auditory meatus to the brain
Where does the ear sit?
Petrous part of temporal bone
Internal carotid artery and internal jugular vein
What shapes receptor is the ear?
Funnel-shaped receptor for aucoustic vibrations
What is the external ear made from?
Elastic cartilage and skin
What muscles can move the ear?
Muscles of facial expression
What is the lymph drainage of the external ear?
To parotid gland and cervical lymph nodes
What is the blood supply to the external ear?
Maxillary and superficial temporal, arteries
What is the nerve supply to the external ear?
Auriculotemporal (anterior) and Vagus (posterior)
How long is the external auditory meatus?
4cm long
Where does the EAM funnel sound to?
Tympanic membrane
What is in the lateral third of the EAM?
Elastic cartilage, hair follicles, sweat and sebaceous glands, ceruminous glands (wax)
What is in the medial two-thirds of the EAM?
Bone lined with stratified squamous epithelium
What way does the tympanic membrane dome?
Towards middle ear
What is the dome shape of the tympanic membrane called?
Umbo
What is the tissue on the lateral and medial aspects of the tympanic membrane?
Lateral = stratified squamous epithelium
Medial = muscles membrane
What is attached to the medial surface of the tympanic membrane?
Malleus
What is the malleus a part of?
A bone of the Ossicles
What is attached to the umbo here?
Malleus of the ossicles
How does the tympanic membrane relay sound waves?
Infayes Intakes in response to sound waves and passes vibrations into the malleus to staples and round window….
Transmit sound waves to the inner ear
What is the blood supply to the tympanic membrane?
Medial side = branches of the maxillary artery and Glossopharyngeal nerve
Lateral = Auriculotemporal and vagus
What is the roof of the middle ear?
Petrous temporal bone
What is the anterior wall of the middle ear?
Auditory tube, tensor tympani muscle
What is the posterior wall of the middle ear?
Aditus & Mastoid antrum (To the mastoid air cells)
Pyramid below attaching stapedius muscle
What pharyngeal arch does the stapedius muscle arise from?
2nd pharyngeal arch
Facial nerve
In the middle ear, where does the pyramid attach to?
Stapedius muslce
What does the stapedius muscle attach to?
Stapes, prevent stapies overvibrating
(Picture showing stapedius muscle)
What supplies the stapedius muscle?
Facial nerve
Stapedius muscle attaches to the pyramid which anchors it to the stapies bone.
A = oval window
B = rouund window
C = stapes bone
What is in the lateral wall?
Tympanic membrane
Chondrite tympani
Epitympanic recess for head of malleus and body of incus
Epitympanic recess located in lateral wall of middle ear
What is in the medial wall?
Oval and round windows
Mainly formed by cochlea
Promontory formed by the cochlea bulges for semi-circular and facial, canals
What is the bulge from the cochlea called?
Promontory - middle ear
What is in the floor of the middle ear?
Thin bony plate separating cavity from jugular foramen and carotid canal
How does the mastoid antrum communicate with the middle ear?
Aditus
How do the mastoid air cells develop?
Develop as diverticula from antrum
Why can an infection spread from the mastoid air cells to the brain?
Separated by thin plates of bone
Cerebellum, temporal lobe and sigmoid venous sinuses
What joint is in the ossicles?
Synovial gliding joints
A = malleus
B = incus
C = stapes
Where does the stapes pass info from and to?
From the tympanic membrane to the oval window
What muscle attaches to the malleus?
Tensor tympani
Attaches to the hammer of the malleus
What is the role of the tensor tympani attaching to the malleus?
Dampen the sound down
The tympanic membrane is not over vibrating
Middle ear/tympanic cavity
What is the tensor tympani continuous with?
Eucatian tube
Wraps around it and controls opening and closing of the tube
What is the nerve supply to tensor tympani?
Mandibular division of trigeminal
