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37 Cards in this Set
- Front
- Back
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A small pupil increases/decreases depth of focus?
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increases
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The pupil is important for reducing chromatic and spherical aberrations. How does this happen?
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reduces peripheral rays
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After refractive surgery, a young patient experiences glare and blur and night. Expain.
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pupil is larger than optical zone of the cornea
so peripheral rays aren't reduced |
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A doctor is doing a swinging flashlight test, and notices that the response is not equal in each eye. What could this indicate?
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nerve or retinal dysfunction
relative afferent pupillary defect |
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A loud noise startles a young child, this will trigger what response of the pupil, by what system?
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pupil dilation
triggers SNS |
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General anesthesia and narcotics will have what effect on pupils?
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miosis
-depresses the CNS, parasympathetics cause miosis |
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Opiates cause dilation/constriction of pupils.
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constriction
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Amphetamines produce dilation or constriction of pupils.
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dilation
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In pathologic anisocoria, interruption in the sympathetic pathway is more noticeable in the dark or light?
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dark
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What can cause fixed or dilated pupils?
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cataract surgery and iris hooks
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What symptoms are experienced by patients who have a dilated pupil due to pharmacologic dilation?
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photophobia
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Light reflex goes through what nucleus before going to the EW nucleus?
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interneurons of pretectal olivary nucleus
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What tract carries information between the pretectal olivary nucleus and the right and left EW nucleus?
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tectotegmental tract
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What is integrated at the interneuron division?
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afferent and efferent information
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Encephalitis causes damage to the posterior commissure, but it ____ the near reflex and _______the light reflex
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spares the near reflex, and damages the light reflex
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In the postganglionic part of the efferent division, what dominates, accommodative fibers or light reflex fibers?
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accommodative fibers
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What is the supranuclear input of the light reflex?
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pretectal nucleus
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Miosis caused by light reflex and near triad have one common final pathway, what is it?
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EW -->ciliary ganglion--> iris sphinctor
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A patient injures the cell bodies of the ciliary ganglion, what reflex will be more prominent after it heals?
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-patient will respond to near stimulus, but not light.
-sprouts are almost all accommodative |
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Where do postganglionic fibers innervate in accomodative and light reflexes?
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accommodative: ciliary muscle contraction
light: iris sphincter |
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Relaxation of the iris sphincter in dilation is passive/active?
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passive
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Contraction of the iris dilator causes an increase/decrease in dilator.
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increases dilation
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Which muscle is stronger, the iris sphincter or dilator?
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spinctor
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What is the pathway of relaxation of the iris sphincter?
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sympathetic neurons in periaqueductal gray area--> supply efferent pupil fibers at EW nucleus--> alpha 2 adrenergic receptors activated --> suppress PNS output --> dilator contraction, sphinctor relaxation
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When sleeping,the baseline is always mitosis/mydriasis?
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miosis
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What is the second neuron of the in the relaxation of iris sphincter?
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ciliospinal center of budge
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What is the third neuron of the relaxation of the iris sphincter?
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superior cervical ganglion
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Where is the first neuron located in the relaxation of the iris sphincter pathway?
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hypothalamus
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What is the 3 neuron pathway to innervate the iris dilator?
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hypothalamus, ciliospinal center of budge, over apex of lung, superior cervical ganglion, course along internal carotid, cavernous sinus, long ciliary nerve, iris dilator
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What are two targets of the third neuron
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-iris dilator via long posterior ciliary n.
-superior division of CN 3 to mullets muscle |
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Catecholamine released by the adrenal glands cause dilation/contraction of the pupil.
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dilation
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What unit is RAPD quantified in?
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log units
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Horners syndrome is problem with the efferent/afferent pathway?
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efferent
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What are some symptoms of hornet's syndrome?
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ptosis
decreased sweating unilaterally miosis on affected side reverse ptosis of lower lid conjunctival injection |
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The iris dilator is controlled by parasympathetic or sympathetic system?
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sympathetic
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In horners syndrome, dilation is slower/faster.
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slower,
bc the dilator is weak |
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If a patient has a cholinergic hypersensitivity, diluted pilocarpine, causes pupils to dilate/constrict?
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a dilated pupils becomes smaller due to supersensitivity
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