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96 Cards in this Set
- Front
- Back
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Speed and bending (refraction) of light regulated by _
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Medium density
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Shorter wavelength rays (gamma, x ray) have _ (higher, lower) energy?
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Shorter wavelength - higher energy
Longer wavelength (microwaves, radiowaves) - longer wavelength, lower energy |
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Only light that is _ (absorbed, reflected) by object will reach the eye
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Reflected
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_ color absorbs all wavelengths
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Black
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_ color reflects all wavelengths
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White
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If the object neither reflects nor absorbs light rays it is _
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Transparent
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Refractive index is _
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Velocity of light in air/velocity of light in substance
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Transparent material curved on one or both sides is called _ - used to refract light rays
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Lens
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_ lens is thick in center and thin edges and forms real image - upside down and reversed left to right
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Convex
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Convex lens _ converges/diverges light?
Concave? |
Converges
Diverges |
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_ lens has thick edges and thin center
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Concave
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Distance beyond convex lens where parallel rays converge to a common point is called _
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Focal length
-1/f = 1/a + 1/b a - distance of point source of light from lens b - distance of focus on other side of lens |
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In convex lens light rays pass through center and bend - T/F
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FALSE - pass through center without bending
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In convex lens image past lens is _
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Upside down and flipped side to side
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Refractive power of lens in convex lens equals to _
In concave? |
1 meter/focal length
Same - with opposite sign |
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Anterior chamber has _ humor
Posterior chamber has _ humor |
Aqueous
Vitreous |
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Light refraction in eye occurs at _ and _
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Cornea and lens
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Light in the eye focuses on _
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Retina
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_ provides most refraction in the eye
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Cornea
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_ changes shape to provide various degrees of refraction
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Lens
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Change of shape of the lens is possible due to control of _ by _
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Zonule fibers by cililary muscles
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When person is focusing on distant object ciliary muscles _ (relax/contract), lens becomes _ , radial muscles _ (relax/contract), pupils become _
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Ciliary muscles - relaxed
Lens - thin and flat Radial muscles - contract Pupils - dilated |
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When person is focusing on close objects, light _ (diverges/converges), ciliary muscles _ (contract/relax), pupils become _ , circular layer muscles _ (contract/relax), eyeballs undergo convergence - medial rotation of eyeballs by _
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Light diverges
Ciliary muscles contract - lens bulges Pupils constrict Circular muscles contract Medial rectus muscles |
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When you need greater depth of focus pupils diameter _ (increases/decreases)
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Decreases
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58 year old male comes into office with eyesight complain - he lost his ability to accomodate that well . On examination his lens is large, thick and less elastic - name condition and how would you correct
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Presbyopia - need bifocals
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Patient presents with nearsightedness (myopia) - what are possible causes, distant objects are focused where and how do you correct it
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Eyeball is too long or too much refractive power in lens
Distant objects are focused in front of retina Correct with CONCAVE lens |
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Patient presents with farsightedness (hyperopia) - possible causes, where do close objects focus and how do you correct
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Eyeball too short or lens too weak
Divergent light rays from close objects focused behind retina Correct with CONVEX lens |
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Patient presents with abnormal lens curvature, some rays are refracted and others not and he lost accomodation completely - condition and correction
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Astigmatism - correct with spherical or cylindrical lenses
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Contact lenses are held in place by _
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Thin layer of tears (refractive index almost same as cornea)
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Advantages of contact lenses
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- Lens turns with eye so greater field of vision
- Lens has little affect on size of object person sees |
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72 year old female presents with disturbed vision, on exam she has cloudy opaque areas on her lens - name her condition, treatment, vision correction and possible causes
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CATARACTS - proteins of lens become denatured initially and coagulate to form opaque areas
Treatment - surgical removal of lens since vision is disturbed Correction - CONVEX lens |
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_ maintains sufficient pressure in eyeball to keep it distended
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Intraocular fluid
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This fluid in the eye is freely flowing, made by ciliary processes and has constant turnover
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Aqeuous humor
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This fluid of the eye is gelatin like, has water and dissolved substances and gets filtered and diffuse at retinal vessels
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Vitreous humor
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Intraocular pressure is due to resistance to outflow of aqueous humor into _
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Canal of Schlemm
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Average intraocular pressure is _
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15 mmHg
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_ used to measure introcular pressure, can be contact or noncontact and can use inward displacement of cornea to measure pressure _
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Tonometer
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Patient presents with blindness that occured within days, intraocular pressure was measured and was found to be 70 mmHg - name condition, why did blindness occured and treatment
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GLAUCOMA - optic nerve axons and retinal artery compressed by increased intraocular pressure on optic disk, nutrients could not get in and cell death occured
Treatment - drops to decrease secretion or increase absorption of aqueous humor, surgery |
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Blind spot of the eye is called _
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Optic disk
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Sensory layer of the eye that prevents scattering of stray light and where phagocytosis of shed photoreceptor particles occurs
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PIGMENTED EPITHELIUM of retina
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Patients with this condition make no melanin, and when they enter bright room light is reflected in all directions
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Albinos
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Outer nuclear layer of retina contains _
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Rods and cones
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Inner nuclear layer of retina contains _
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Interneurons (excitatory and inhibitory), amacrine, horizontal and bipolar cells
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Axons from _ make optic nerve
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Ganglion cell layer
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Part of photoreceptor that contains photopigment
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Outer segment
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Photopigment of rods
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Rhodopsin
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Photopigment of cones
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Pigment sensitive to red, blue and green
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Part of photopigment that contains nucleus, mitochondria and other organelles and synthesizes photopigment
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Inner segment
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Part of photoreceptor that contacts one or more bipolar cells and releases NT with no light stimulation
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Synaptic body
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This receptor is monochromatic, it is more effective in dark, bleached in daylight and located mostly in periphery. Allows low visual acuity
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RODS
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This photoreceptor is trichromatic, has no efficiency in dark but highly effective in light,located mostly in fovea and allows high visual acuity
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CONES
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Central retinal artery enters via _
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OPTIC NERVE
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Highly vascularized layer between retina and sclera is called _
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Choroid
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When light rays enter the eye they excite _ which excite _ and _ which provide lateral communication. _ cells than excite ganglion cells and amacrine cells
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Photoreceptors
Bipolar cells Horizontal cells Bipolar cells |
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ONLY _ GENERATE ACTION POTENTIALS - all others generate _
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GANGLION CELLS
Receptor potentials |
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This cell layer in retina is constantly tonically active
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Ganglion cell layer
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NO LIGHT - nonselective cation channels are _ and membrane is constantly _ . _ bound to the channel keeps it open. Na/K and Na/Ca exchangers help maintain ionic balance
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Open
Depolarized cGMP |
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LIGHT STIMULATION _ changes into active form and activates transducin. Transducin associates with _ , _ is inactivated, without it Na channels close and membranes _
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Rhodopsin
cGMP cGMP Hyperpolarize |
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Patient complains of night blindness - what is he probably suffering from and how can you reverse that
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Chronic vitamin A defficiency - decreased formation of retinal acid and rhodopsin
Reverse with IV vitamin A |
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Dark increases/decreases pupil size
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Dark increases pupil size, light constricts
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This phenomenon enhances contrast and is achieved by horizontal cells
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Lateral inhibition
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Stimulation of the center of this cell excites cell and stimulation of surround hyperpolarizes it
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On-center, off-surround
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Stimulation of the center of this cell hyperpolarizes cell and stimulation of surround excites it
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Off-center, on-surround
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Main functions of auditory system are _
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Localization of sound
Characteristic sounds |
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Central organizing principle of auditory system is _
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Frequency
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In young adult human normal hearing range is _
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20Hz to 20000 Hz
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Most sensitive range of hearing in human is _
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1000-4000 Hz
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These two ossicles act together as single lever - _ and _ When _ moves footplate of _ applies pressure at oval windown
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Incus and malleus
Malleus Stapes |
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Handle of _ is pulled inward by tensor tympani - better transmission at tympanic membrane
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Malleus
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Middle ear ossicles function in _ reflex - contraction of stapedius muscle
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Attenuation
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_ causes travelling wave that runs along the basilar membrane
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Action of footplate of stapes at oval window
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Hair cells have vertical _ projecting from apical surface
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Stereocilia
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Tips of adjacent stereocilia are connected by _
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Tip links
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Deflection of stereocilia towards the talles member results in _
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Opening of cation channels and depolarization
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Scala vestibuli and scala tympani contain _ - similar in composition to CSF
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Perilymph
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Scala media contains _ made by _ - this solution is high in K and low in Na
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Endolymph
Stria vascularis |
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Stereocilia and rest of hairs are separated by _
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Reticular lamina
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Resting potential of hair cell is _
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- 60 mV
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_ makes hair cells very sensitive to vibrations of basilar membrane
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Huge electric potential
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Displacement of basilar membrane results in :
_ of hair cell Opening of voltage gated _ channels Release of _ Opening of _ channels (repolarization) |
Depolarization
Ca NT Ca dependent K channels |
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Position along the basilar membrane that vibrates determines frequency of sound - this is called
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Place code
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These frequencies are likely coded in cochlear nuclei and not in basilar membrane (destruction of basilar membrane doesnt eliminate them)
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Low frequencies - less then 200 Hz
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When you play sound in the air you can record sound that is coming back . This is called _
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Otoacoustic emission
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Receptive fields of many auditory neurons are influenced by _
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Inhibition
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_ plays essential role in sound localization
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Superior olivary complex
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_ sounds are deflected by the head and acoustic shadow is formed - arrival at distant ear has lost some intensit
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High frequency (2-20 kHz)
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_ are utilized to locate high frequency sounds in azimuth
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Interaural intensity disparities
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Binaural neurons are formed in _
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Inferior colliculus
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Sensorineural deafness refers to _ and _ caused by _
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Complete deafness
High frequency hearing loss Auditory nerve or cochlea damage |
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In conductive hearing loss there is no _ conduction but _ conduction is possible, common cause is _
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Air conduction
Bone Otosclerosis |
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Ringing in ears is called _
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Tinnitus
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Age related hearing loss is called
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Presbycusis
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Tumor that commonly causes damage to auditory nerve and deafness is called _
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Acoustic neuroma
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Weber test is testing _ . In this test you place tuning fork on _ and normally sound is loudest in _ . With conductive hearing loss sound seems louder in _ , with sensorineuronal hearing loss seems louder in _
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Bony conduction
Forehead Midline (equal in both ears) Affected ear (ossicles dont move - no ambient noise) Normal ear |
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In Rinne test you compare _ .You place tuning fork on _ . Then you move tuning fork _ . Normally _ , in conductive hearing loss there are no _
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Air and boney conduction
Mastoid In front of ear Still hear by air conduction Air vibrations |
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In order for cochlear implant to work what need to be intact
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Auditory nerve
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