Flashcards in 6.1 The Ear Deck (29):
What makes up the external ear?
External auditory canal
What makes up the middle ear?
Mastoid air cells
Facial nerve (chorda tympani)
What makes up the inner ear?
What is a pinna haematoma?
Haematoma between the cartilage and the perichondrium which prevents oxygenation of tissue resulting in avascular necrosis
What is cauliflower ear?
Ear collapses in and structure is lost after repeated injuries (eg rugby injuries)
Which glands form ear wax?
What is the function of ear wax?
Cleans the ear
What is the tympanic membrane also known as?
Which way does the cone of light point on the tympanic membrane?
Inferiorly and anteriorly
Give 2 causes of tympanic membrane rupture
Name the 3 bones of the middle ear
What type of joint joins the bones of the middle ear?
What is the function of the eustachian tube?
Equalises the pressure between the ear and the GI tract
What is the function of the mastoid air cells?
Aerate the middle ear
Name the 2 muscles in the middle ear
Tensor tympani and the stapedius
What nerve innervates the tensor tympani?
CN V2 branch
What nerve innervates the stapedius muscle?
Why are children more at risk of eustachian tube dysfunction?
Tube is shorter and wider and so more at risk of infections travelling up from the mouth
What is otitis media?
Inflammation of the middle ear leading to retraction of the ear drum.
What is glue ear?
Accumulation of thick effusions behind the ear drum
What is mastoiditis?
Inflammation of the mastoid air cells. Pus forms and increases the pressure in the ear
What is cholesteatoma?
Negative ear pressure causes retraction of the tympanic membrane. Dead cells accumulate as a necrotic mass (cholestoma). Lytic enzymes are released and erodes the middle ear
What bone surrounds the inner ear?
Which part of the inner ear allows hearing?
How does the cochlear work?
Radial structure with sensory cells. The sensory cells have a given frequency at which they will resonate. This produces an electrical signal which the brain recognises as sound
Which part of the ear controls balance?
Vestibular compartment- utricle, saccule, 3 semi-circular canals
How does the vestibular compartment control balance?
Fluid in the semicircular canals and the saccule moves and hits the collagenous matrix. Depending on which area of the vestibular can detect the fluid, the brain can work out its orientation
What is BPPV?
Benign Positional Paroxysmal Vertigo
Extra sediment in the inner ear fluid moves slower than the fluid. Eg. When the head turns the fluid moves so the brain recognises the movement. However the sediment still moves even when the body has stopped. Person feels as if they are still moving even when they are not