Hearing + The Ear Flashcards
What is presbycusis?
Loss of hearing with age
Where does conductive hearing loss occur?
Outer + middle ear
Where does sensi-neuronal hearing loss occur?
Cochlea, auditory nerve, central auditory pathways
What detects balance?
Semicircular canals
What is serous otitis media?
Problem with drainage along Eustachian tube
Use grommets to provide alternative drainage
What is the role of ossicles?
Tympanic membrane = large SA but force from sound vibrations ins air = weak
Ossicles concentrate force onto smaller area of oval window
Increases efficiency of transmission
What makes up ossicles?
Malleus = hammer Incus = anvil Stapes = stirrup
What is ostosclerosis?
Calcification of joints - Interferes with free movement of ossicles
Describe the layers of the cochlea
Scala vestibuli > Scala media > (basilar membrane) > Scala tympani
What is the the hearing organ?
Organ of corti
Describe the srtucture of the organ of corti
Basilar membrane > nerve cells > hair cells > tectorial membrane
Where is there a high Na in the orogan of corti?
Perilymph = Scala vestibuli + Scala tympani
Where is there a high K in the organ of corti?
Endolymph = Scala media
What produces the endolymph?
Stria vascularis - has Na/K pump
What is waardenburg syndrome?
Cells that control K+ secretion in stria vascularis fail to migrate into tissue during development = deafness as no endocochlear potential
