Special Senses Flashcards
Function of outer ear
Transfer sound waves via ear drum
Bones of middle ear
Ossicles: Malleus, Incus, Stapes
Function of ossicles
Amplify sound from eardrum to inner ear
Structure that contains basilar membrane
Cochlea
Area of inner ear that best detects low frequency sounds
Apex of basilar membrane near helicotrema
Area of inner ear that best detects high frequency sounds
Base of cochlea
Location of tuning fork in Rinne test
Next to ear
Purpose of Rinne test
Test for conductive hearing loss
Abnormal Rinne test for conductive hearing loss
Bone conduction > Air conduction
Location of tuning fork in Weber test
On top of head
Purpose of Weber test
Localizes
Abnormal Weber test for sensorineural hearing loss
Sound localizes to good ear
Normal Rinne test
Air conduction > Bone conduction
Abnormal Weber test for conductive hearing loss
Sound localizes to bad ear
Normal Weber test
Sound heard equally in both ears
Aging related sensorineural hearing loss
Presbycusis
Mechanism of presbycusis
Destruction of hair cells at cochlear base
Overgrowth of desquamated keratin debris within middle ear space leading to conductive hearing loss
Cholesteatoma
Sensation of spinning while actually standing
Vertigo
Types of vertigo
Peripheral and Central
Etiology of peripheral vertigo
Inner ear defect
Etiology of central vertigo
Brain stem or cerebellar lesion
Which type of vertigo is more common
Peripheral
Causes of peripheral vertigo
Semicircular canal debris, vestibular nerve infection, Meniere disease, benign paroxysmal positional vertigo
Findings in central vertigo
Directional or vertical nystagmus, skew deviation, diplopia, dysmetria
Positional testing results in central vertigo
Immediate nystagmus in any direction, focal neurologic findings
Positional testing results in peripheral vertigo
delayed horizontal nystagmus
Outer layer of the eye
Sclera
Middle layer of the eye
Choroid
Inner layer of the eye
Retina
Structures within the optic canal
Optic nerve, central retinal vein and artery
Most common cause of conjunctivitis
Viral (adenovirus)
Presentation of viral conjunctivitis
Sparse mucus discharge and swollen preauricular lymph nodes
Treatment for bacterial conjunctivitis
Antibiotics
Presentation of allergic conjunctivitis
Bilateral itchy eyes
Presentation of bacterial conjunctivitis
Pus from infected eye
Where is light focused in relation to retina in hyperopia
Behind retina
Farsightedness
Hyperopia
Type corrective lens needed for hyperopia
Convex (converging) lens
Nearsightedness
Myopia
Type corrective lens needed for myopia
Concave (diverging) lens