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Details Title: Ocular Physiology Test 1 Description: Eyelid structure and function Part 2 Total Flash Cards: 76 Created: 09/22/2007 19:03:59	To study from this set of flash cards, or to create your own your own study flash cards, register HERE. If you are already a registered user, CLICK HERE.
Cards Term Is the palpebral or orbital orbicularis more excitable? Definition Palpebral Term What part of the orbicularis is involved in rapid blinks, reflex, spontaneous blinks and basic blinks? Definition Palpebral Term What part of the orbicularis is involved in forced closure blinks? Definition Orbital Term The levator palpebrae superioris elevates what part of the lid? Definition Upper lid Term Are the right and left levator palpebrae superioris yoked? Definition Yes - they receive equal innervation Term What muscle is responsible for the tonic lid position? Definition Tarsal muscle of Meuller Term The superior tarsal muscle of Meuller runs from the levator palpebrae superioris connective tissue sheath, under the levator palpebrae superioris itself, and finally to where? Definition Superior tarsal plate Term The inferior tarsal muscle or Mueller runs from where to the inferior tarsal plate? Definition IR/IO connective tissue sheath Term What is the only muscle that depresses the lower lid? Definition Tarsal muscle of Meuller Term The Meuller muscle receives what type of nervous system innervation? Definition Sympathetic Nervous system Term What is Bell's phenomenon? Definition It is the upward and outward rotation of the globe that happens with forced closure and sleeping. It is a normal protective response Term The Bell's phenomenon signals an intact what in an unconscious patient? Definition Intact midbrain Term When will Bell's phenomenon disappear? Definition If you have a brainstem lesion above the pons Term Are Bell's phenomenon and Bell's Palsy the same thing? Definition NO - Bell's palsy involves twitching, weakness, or paralysis of the face due to irritation of the facial nerve (CN 7) Term How does the lid receive its sensory innervation? Definition Through the ophthalmic branch (V1) of the Trigeminal nerve (CN 5) Term The sensory plexus for the lid is deep to the palpebral fibers of the orbicularis oculi so it requires what for anestheses? Definition Deep penetration Term Is a hordeolum or a chalazion painful? Definition A hordeolum Term What is preseptal cellulitis? Definition An infection of the preseptal region of the eyelid. It can start as a hordeolum Term What is the eyelid disorder that is marked by cholesterol deposits on the upper medial eyelid margin? Definition Xanthelasma Term In spastic entropion this portion of the orbicularis oculi is overeactive and causes override of the tarsal portion. Definition Septal portion Term What is atonic ectropion of the lower lid? Definition It is a loss of orbicularis oculi tonus Term Paralytic ectropion of the lower lid is caused by what? Definition Flaccid paresis of CN 7 Term Ankyloblepharon is characterized by what? Definition Adhesions of the upper and lower lid Term What is blepharophimosis? Definition Inverted epicanthal folds Leads to reduced fissure Term What is cryptophthalmos? Definition It is where there is no lid opening at all - lids are fused Ankyloblepharon totale Term What causes a coloboma? Definition Failed closure of the fetal fissure Term What is blepharochalasis? Definition It is a loss of orbital septum allowing a fat prolapse - saggy lids Term Are the elderly the only people to get blepharochalasis? Definition NO - Young people can get the condition following chronic edema Term Is blepharochalasis a ptosis? Definition NO - The input and tonus of the levator is normal but the tissues are drooping. It is a Psuedotosis Term What can cause a blepharospasm? What does it look like? Definition An irritated CN 7 can cause it. The eyelids will not unclamp Term What is a myokymia? What causes it? Definition It is an eyelid twitch. It can be caused by stress, lack of sleep, or idiopathic reasons Term In Bell's palsy, are emotional or voluntary actions affected? Definition Not as affected It is mainly your voluntary actions that are affected Term What are some symptoms of Bell's palsy? Is it usually bilateral or unilateral? What percentage usually recovers? Definition Lagophthalmos and widened palpebral fissure, facial twitching, etc Usually unilateral 86% recover completley Term The restinf lid position depends upon the resting tonus of what two muscles? Definition The levator palpebrae superioris and Mueller's muscle Term The resting lid position can vary with what state? Definition Your arousal state (serum level of catecholamines) Term If there is asymmetry between your two vertical palpebral fissures is this a problem? Definition YES - It has pathological significance Term In congenital ptosis, with downgaze the normal lid moves where? Definition Lower Term What causes a Psuedo-Grafe? Definition Abberant regeneration of CN 3 Term What are some signs and symptoms of a Pseuo-Grafe? Definition It is a mix-up of what should normally happen with the eyelids. Ptosis, lid elevation with downgaze or adduction. You may have a pupil that is non-reactive to light but that constricts with adduction. Term In Marcus-Gunn Phenomenon what happens because of bad wiring between the brain, jaw and lid? Definition “Jaw winking” – lid retraction with mouth open or lateral jaw movement Term What is Collier’s sign? Signs and symptoms? Definition Symmetric upper lid retraction – 2nd most common cause of lid retraction Characteristic stare (staring all the time) and commonly upgaze paresis Term What causes Collier’s sign? Definition Pretectal/dorsal midbrain lesion Term What is the most common cause of lid retraction? Definition Hyperthyroidism – Grave’s Disease Term What is Dalrymple’s Sign? Definition Widening of the palpebral fissure due to excessive tonus of Muller muscle or excessive tonus of the levator palpebrae Term Widening of the palpebral fissure due to retraction of the upper eyelids is responsible for the apparent exophthalmos seen in what? Definition Thyrotoxicosis – Complication associated with Grave’s disease Term The principal reason for the prominent appearance of the eye is what? Definition Lid retraction Term With Von Graefe’s Sign, the patient manifests a “lid-lag” because of a mismatch of signals between the globe and lid. In downgaze, what can be seen in these patients? Definition Inability of the upper lid to follow the movements of the globe Term What is a blepharospasm? Definition Bilateral, involuntary intermittent or persistent spasmodic closure of the eyelids with active contraction of the orbicularis oculi and the procerus and corrugator muscles. Term What is blepharoptosis? Definition Drooping of the upper eyelid due to paralysis of the occulomotor nerve (CN3) or sympathetic nerve or by excessive weight of the upper eyelids Term What is blepharoclonus? Definition Exaggerated reflex blinking Term What is blepharophimosis? Definition Decreased size of the palpebral fissure, often due to increased distance between the inner canthui (telecanthus) or drooping upper eyelid (blepharoptosis) Term The eyelids close in a zipper fashion. What moves where? Definition Upper eyelid moves down and nasal, the lower lid moves nasally (depressed momentarily when contracted by upper lid), the lateral canthus moves nasally and the medial canthus stays stationary Term Of the three types of blinking, spontaneous, reflex, and voluntary, which is the most common yet the mechanism is the least understood? Definition Spontaneous Term Reflex blinking can be elicited by what kind of stimulation? Definition Sensory – touch, auditory, light, irritation Term Voluntary blinking is accomplished by what two parts of the orbicularis oculi? Definition Preseptal and pretarsal Term Spontaneous (basic) blinking is elicited by what muscle? Definition Palpebral orbicularis oculi Term Are basic blinks (spontaneous) 100% complete? Definition NO – 75% complete under ideal conditions. They can be even less complete when attending to something or doing activities (ie computer). Term How many spontaneous blinks does an adult average per minute? Newborn? Definition Adult – 12-15x/min Newborn – less than 3x/min Term Although the reflex stimulus that initiates a spontaneous blink is largely unknown, what do some believe it is do to? Definition The tear film becomes hypertonic with increased exposure to the air. This is then detected by nerve endings (eyelid? eye?) which then stimulate the lid to come down Term Can your number of basic blinks vary? Definition YES – Can vary with stimuli, conditions, or emotion Term Blinking data shows that you can _______ your eye twice as fast as you can ______ it. Definition Close; open Term In a protective tactile reflex blink, what are the afferent and efferent pathways? Definition Afferent – CN5 to Gasserian ganglion to midbrain Efferent – CN 7 nucleus to orbicularis oculi Term Does a tactile reflex blink require cortical input? Can it be reduced with CL wear? Definition YES – absence most commonly due to CN 5 damage YES Term How do you quantify a tactile reflex blink? Definition An aesthesiometer or cotton wisp Term You receive a visual reflex that suprises you or dazzles you. What are the afferent and efferent pathways? Is it cortically dependent? Definition Afferent – CN 2 to superior colliculus and supraoptic nuclei Efferent – CN 7 nucleus to orbicularis oculi It is not cortically dependent – it is entirely brainstem mediated Term How can this dazzle reflex blink be lost? Definition With a mesencephalic lesion Term You receive a visual reflex that appears to be menacing. What are the afferent and efferent pathways? Is it cortically dependant? Is it a learned reflex? Definition Afferent – CN 2 to LGN to primary visual cortex and associated fibers to Rolandic area Efferent – CN 7 nucleus to orbicularis oculi It is cortically dependent – requires input from occipital lobe and parietal and frontal lobes mediate your visual attention It may be a learned reflex (after age 2-4 months) Term A book drops on the floor unexpectedly and elicits a auditory (stapedius) reflex blink. What are the afferent and efferent pathways? Definition Afferent – CN 8 to auditory nucleus Efferent – CN 7 nucleus to orbicularis oculi Term The cortical control of an elevating lid movement occurs where? Definition Frontal cortex (oculogyric center) Term The cortical control of a closure lid movement occurs where? Definition Motor cortex (precentral gyrus) Term The eyelids move with similar speed and conjugacy to what EOM’s? Definition Vertical Term In downgaze, the upper lid depresses due to the relaxation of what muscle and the tonus of what other muscle? This is an example of what law? Definition Relaxation of the levator palpebrae superioris and tonus of orbicularis oculi Sherrington’s Law Term The upper eyelid elevates with upgaze synergistically with what muscle? Why does this occur? Definition Superior rectus; they share a common facial sheath Term Is there an association of ptosis and superior rectus palsy? Definition YES Term Both levator palpebrae superiori are under the control of what nucleus of CN3? Definition Central caudate nucleus Term In the midbrain, what nucleus inhibits the central caudate nucleus? Definition Nucleus of posterior commisure Example – In downgaze the nucleus of posterior commisure fires and inhibits the central caudate nucleus allowing eyelid relaxation