Ear anatomy and physiology Flashcards
what is the name for the external ear?
auricle or pinna
what is the auricle composed of?
skin
stratified keratinising squamous epithelium
elastic cartilage
what is the external acoustic meatus composed of?
lateral 1/3 cartilage and skin
medial 2/3 bone and skin
what is earwax produced by?
ceruminous and sebacious glands
what are the 3 layers of the tympanic membrane?
outer squamous epithelial
middle fibrous connective tissue
inner columnar ciliated mucus membrane
what can cause suppuration in the tympanic membrane?
perforation by trauma
what are the 3 small bones in the ear called?
hammer - malleus
anvil - incus
stirrup - stapes
what does the ossicular chain play a key role in?
sound conduction
what happens if there is trauma to the ossicular chain?
chronic suppuration
bony sclerosis
what tendon attaches to the stapes?
stapedius tendon
what is the middle ear lined by?
columnar ciliated epithelium
what does the middle ear contain?
ossicles
facial nerve
chorda tympani
what is the middle ear connected to?
the mastoid system via aditus
post nasal space via eustachian tube
what are the 2 parts of the tympanic cavity?
epitympanum
hypotympanum
what are the dangers of infection/trauma to the facial nerve?
intracranial sepsis
facial nerve damage
deafness
dizziness
where is the vestibulo located?
inner ear
what is the purpose of the vestibulo?
cochlear organ (balance and hearing)
what are the components of the bony labyrinth?
cochlea
vestibule
semi-circular canal
what is the membranous labyrinth composed of?
sensory epithelium
what are the 2 types of fluid in the inner ear?
perilymph
endolymph
where does the internal auditory meatus join the brainsteam?
junction of pons and medulla
what innervates the ear?
cervical nerve root branches trigeminal nerve glossopharyngeal nerve vagus nerve branches of the vestibulocochlear nerve
what does the inner auditory meatus contain?
7th and 8th cranial nerves
what is the clinical significance of the internal auditory meatus
site of aucostic neuroma and vestibular schwannoma
what has the greatest effect on hearing loss?
loss of ossicular continuity (compared to perforation of the tympanic membrane)
