Term
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Definition
| Sound wave-->Air-> External auditory canal -> Tympanic Membrane -> Moves malleus -> Incus -> Stapes -> Inner Ear Pressure change -> Triggers wave in basilar membrane of Cochlea -> Bends Receptor Hairs |
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Term
| Where do high Frequency tones displace hair? |
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Definition
|
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Term
| What happens as tones get lower? |
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Definition
| Point of maximal membrane displacement moves toward the cochlear |
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Term
| What is Conductive Hearing loss? |
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Definition
| Transmission of sound through air is blocked. Can still hear through bone CONDUCTION |
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Term
| What are some causes of Conductive hearing loss? |
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Definition
| Wax, foreign object, otitis externa, tympanic membrane perforation, otosclerosis |
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Term
| What is Sensory hearing loss? |
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Definition
| Disorders of the cochlea, cochlear nerve, central pathways |
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Term
| What are some causes of Sensorineural hearing loss? |
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Definition
| Congenital, Presbycusis, Viral, ototoxicity, trauma, Meniere's disease, vestibular schwannomas |
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Term
| What can cause Mixed hearing loss? |
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Definition
| otosclerosis, temporal bone fractures, chronic middle ear infections, middle ear tumors and some inner ear malformations |
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Term
| What are the sypmtoms of Meniere's disease? |
|
Definition
| Vertigo, fluctuating sensorineural hearing loss and tinnitus |
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Term
| How is Meniere's Disease Treated? |
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Definition
| Low salt diet and diuretics |
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Term
| What is the pathophysiology of Meniere's disease? |
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Definition
| an increase in volume and pressure of the endolymph of the inner ear |
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Term
| During a clinical assessment of hearing loss what do you want to inquire about? |
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Definition
| Duration, change over time, associated symptoms, vertigo, earache, family Hx |
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Term
| If Bone conduction is greater than air conduction in the Rinne Test, the patient has what? |
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Definition
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Term
| What are the results of the Rinne and Weber test in someone who has Sensoriheural hearing loss? |
|
Definition
Rinne: Air conduction greater than Bone Conduction in Both ears
Weber: Sound Louder in Normal Ear |
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Term
| In a conductive hearing loss, the sound will lateralize to which ear? |
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Definition
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Term
| What disease is associated with an audiogram pattern that results in a greater threshold elevation in the lower frequencies? |
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Definition
| otosclerosis - caused by fixation of the footplate of the stapes |
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Term
| What does the typmanogram measure? |
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Definition
| impedance of the middle ear to sound |
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Term
| What would an audiogram show for middle ear effusions? |
|
Definition
| greater elevation of thresholds in Higher frequencies |
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Term
| What does Sensorineural hearing loss look like on audiogram? |
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Definition
| steadily rising threshold elevations with increasing frequencies - (the higher the frequency the worse the hearing) |
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|
Term
| What does noise induced hearing loss usually show? |
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Definition
| selectively greater loss at 4000Hz |
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|
Term
| What are the characteristics of Otosclerosis? |
|
Definition
| Conductive Hearing Loss, progressive sensorineural, starts in 20-30s, Bilarteral, +Family Hx |
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Term
| What does a patient typically present with if they have a vestibular schwannoma? |
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Definition
| Sensorineural hearing loss, NO Vertigo |
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|
Term
| What are the cardiac causes of syncope? |
|
Definition
| cardiac arrhythmias, heart failure, obstuction of cardiac outflow, pulmonary embolism |
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Term
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Definition
| an illusion of movement typically described as spinning of whirling |
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Term
|
Definition
| Disease of the vestibular system, peripherally or centrally |
|
|
Term
| What is the clinical sign of vertigo? |
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Definition
|
|
Term
| What monitors the position of the head in space by detecting angular, static and linear acceleration? |
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Definition
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|
Term
| What part of the vestibular system detects linear motion and gravity? |
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Definition
|
|
Term
| How are the Sacculus and utricle alined? |
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Definition
sacculs-coplaner with vertical axis
utricle-coplaner with the horizontal axis |
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|
Term
| What detects angular movements? |
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Definition
|
|
Term
|
Definition
| crystals of calcium carbonate on top of the gelatinous matrix that the sensory heair cells of the saccule and utricle |
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Term
| How does the distortion of the hair cell produce a signal in the vesitibule? |
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Definition
| Force on Kinocilium -> opens (or closes) K+ channels on other cilia -> depolarizes cell membrane -> activates Ca+ channels -> Ca+ influx -> Neruotransmitter released |
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Term
| How is the signal from the vestibule regulated? |
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Definition
Force Toward Kinocilium -> Increases Neurotransmitter release -> activates afferent fivers from Scarpa's ganglia
Force Opposite Kinocilium -> Decreases neurotransmitter -> decreases impulses |
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|
Term
| Where do the bodies of the sensory nerve fibers at the hair cells base lie, and where do they project to? |
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Definition
| Scarpa's ganglion, Brainstem via vestibular nerve |
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Term
| How do the kinocilium face in the utricle? |
|
Definition
| toward a midline valley called the striola |
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Term
| What two kinds of forces with alter the firing rate in the Utricle? |
|
Definition
Linear force within the plane of the utricle
Static gravitational force when the plane is tilted |
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Term
| How is the kinocilia oriented in the saccule? |
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Definition
|
|
Term
| If you stand in an elevator that starts to move up what part of the saccula is activated? |
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Definition
|
|
Term
| How are the hairs oriented in the ampulla? |
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Definition
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|
Term
| A net increase in firing from the left vestibular apparatus will cause the eyes to move which way? |
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Definition
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Term
| How can you "Rule In" psychogenic unresponsiveness as the cause of coma? |
|
Definition
| demonstrating that ice water in either ear induces nystagmus |
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Term
| If a patient requires saccadic refixation with head thrust maneuver to the left, where is there a lesion? |
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Definition
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|
Term
| In the Dix-Hallpike maneuver, how do you maximally stimulate the right posterior canal and maximally inhibit the left anterior canal? |
|
Definition
| Turing the head Right and falling back from a sitting to lying position |
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Term
| How is Peripheral vertigo with nystagmus chararcterized? |
|
Definition
Latency of onset
subsides over 1-2 min
Nystagmus increases with gaze away from lesion
mixed horizontal-torsional
Habituates with repetition |
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|
Term
| How is Central vertigo with nystagmus characterized? |
|
Definition
No latency of onset
Sustained with position (does not improve with visual fixation)
No increase, may change direction with chage of gaze
Single Plane nystagmus
Does Not Hapituate |
|
|
Term
| What is Benign paroxysmal positional vertigo (BPPV) and what causes it? |
|
Definition
Peripheral Vertigo, Otoconia break free and collect in the posterior semicircular canals, causes greater distortion of the cupula in the ampulla then there really is.
Starts 5-10 seconds after head movement, lasts 30-45 seconds |
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|
Term
| What is the most common cause of vertigo (especially in the elderly)? |
|
Definition
| Benign Paroxysmal Positional Vertigo |
|
|
Term
| What type of vertigo is often triggered by looking up as they reach for a high shelf? |
|
Definition
|
|
Term
| What is a less common cause of BPPV where particles reach the cupula? |
|
Definition
|
|
Term
| What is one of the posterior canals functions? |
|
Definition
| To maintain visual fixation via the vestibulo-ocular reflex |
|
|
Term
| If the right posterior canal is occluded, What will the Dix-Hallpike maneuver show? |
|
Definition
| Head turned Right, Eyes Looking Left, causes upbeat vertical hystagmus in plane of Rt. Post. Semicircular canal, if patient looks right, corrective movement becomes torsional |
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|
Term
| What's the course light takes to get to the fovea? |
|
Definition
| Refracted by cornea-> inverted through pupillary opening-> refracted by the lens-> Projected on the fovea |
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|
Term
| What protects the Retina and Choroid? |
|
Definition
|
|
Term
|
Definition
| vascular layer for retina |
|
|
Term
| How is the visual axis maintained on the fovea? |
|
Definition
|
|
Term
| What provides a barrier from the retina to the choroid? |
|
Definition
|
|
Term
| What is the Retinal pathway of cells? |
|
Definition
| Photoreceptors to bipolars to ganglion cells |
|
|
Term
| What are the 2 interneurons of the retina called? |
|
Definition
| Horizontal cells and amacrines |
|
|
Term
| What cells coalesce to form the optic nerve head, Blind Spot? |
|
Definition
|
|
Term
| What layer of the retina absorbs light? |
|
Definition
| Retinal Pigmented Epithelium - contains melanin |
|
|
Term
| What are the 2 main functions of the Retinal pigmented epithelium? |
|
Definition
| Seperate the choroid from the retina, Phagocytosis of rod outer segments |
|
|
Term
| What processes black and white info? |
|
Definition
|
|
Term
| Where is light detected and transduced by the rods? |
|
Definition
|
|
Term
| How often are rod outer segments phagocytosed? |
|
Definition
|
|
Term
| What photoreceptors process color? |
|
Definition
|
|
Term
| What are the 3 types of Cones? |
|
Definition
L-cones - long wavelengths
M-cones - medium wavelengths
S-cones - short wavelengths |
|
|
Term
| What cones represent blue? Green? Red? |
|
Definition
Blue - S-Cones
Green - M-cones
Red - L-cones |
|
|
Term
| Why are men often red-green color blind? |
|
Definition
| M- and L- cones are carried on X chromosome |
|
|
Term
| What kind of response do cones and rods have with the stimulation of light? |
|
Definition
|
|
Term
| How is rhodopsin activated? |
|
Definition
| Light absorption converts 11-cis-retinal to all-trans-retinal which activates rhodopsin |
|
|
Term
| What does Transducin dissociate into after GDP is replaced by GTP? |
|
Definition
| Talpha-GTP and T-betagamma |
|
|
Term
| What activates cGMP phosphodieterase? |
|
Definition
|
|
Term
| How do the cation channels re-open? |
|
Definition
| efflux of Ca+ reduces cytosolic Ca, inhibits PDE -> cGMP levels rise toward pre-stimuls levels |
|
|
Term
| How is Rhodopsin reactivated? |
|
Definition
| RK phosphorylates "bleached" rhodopsin, Arrestin binds, inactivating rhodopsin, slowly arrestin dissociates, rhodopsin is dephosphorylated, all-trans->11-cis |
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|
Term
| What do horizontal cells do? |
|
Definition
| help converge the signals from multiple rod photocells to fewer Rod Bipolar cells. (same for cones) |
|
|
Term
| What are transient ischemic attacks affecting the vision of one eye usually caused by? |
|
Definition
| platelet thrombin emboli from atheromatous plaques in the carotid artery on the same side |
|
|
Term
| What symptom would you suspect basilar artery insufficiency? |
|
Definition
| transient loss of vision in both eyes simultaneously |
|
|
Term
| What are some examples of painless loss of vision? |
|
Definition
| cataract, central retinal artery or vein occlusion, retinal detachment |
|
|
Term
| Pain on eye movement accompanied with loss of central vision and a relative afferent pupillary defect are common in what? |
|
Definition
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