quiz 3
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47 terms
Terms | Definitions |
|---|---|
 saccades | rapid jumping eye movements |
| smooth pursuit | smooth eye movement that tracks an object |
| vergence | eyes move toward or away from each other |
| vergence (convergent) | eyes move toward eachother |
| vergence (divergent) | eyes move away from eachother |
| Vestibulo-ocular reflex (VOR) | eye movement using smooth pursuit to track an object |
| Optokinetic nystagmus | eyes start to shake when looking far left |
| superior colliculus is affected by __ | several cortical and subcortical sites |
| superior colliculus | activates certain movement |
| general functions of the vestibular system | 1. contribute to sense of movement and balance 2. stabilize vision during head movement (VOR) 3. regulate postural tone |
| specific functions of vestibular system | transduction of angular/linear velocities & accelerations and transduction of the gravitational vector |
| vestibular system is housed in the __ | inner ear |
| vestibule | main body of vestibular system, continuous with cochiea |
| cochela | auditory receptor. sound waves get converted to action potentials |
| purpose of semicircular canal | transduce angular accelerations of the head |
| 3 types of semicircular canals are: | horizontal, posterior, and anterior/superior |
| horizontal semicircular canal | used in "no" motion |
| posterior semicircular canal | used in "yes" motion |
| anterior/superior semicircular canal | used in "don't know" (shrugging shoulders) motion |
| semicircular canals are filled with ___ | endolymph |
| cupula | gelatinous structure that interrupts fluid flow and is inside the ampulla |
| ampulla | widest region of semicircular canal |
| hair cells that extend into the cupula ___ | transform mechanical energy into neural activity |
| hair cells in cupulas are composed of ___ and ___ | many stereocilia and one kinocilium |
| when stereocilia are pushed towards the kinocilium the hair cell ___ | depolarizes |
| when stereocilia are pushed away from the kinocilium the hair cell __ | hyperpolarizes |
| excitation | stereocilia is pushed towards kinocilium in the left semicircular canal |
| inhibition | stereocilia is pushed away from kinocilium in the right semicircular canal |
| purpose of otolith organs | transduce linear accelerations of the head |
| utricle | horizontal linear acceleration |
| saccule | vertical linear acceleration |
| otoliths | carbonate crystals embedded into macula |
| normal vestibular function relies on the equivalent densities (or specific gravity) of ___ and ___ | endolymph and cupula |
| cutaneous receptors that receive information regarding pressure | merkel's discs and pacinian corpuscle |
| proprioception | knowledge of body position in space |
| sensory receptors of proprioception are: | muscles, tendons, and joints |
| muscle spindles | tell you length of skeletal muscles in your body |
| golgi tendon organs : "GTO's" | sensitive to changes in muscle force/tension - activated when muscle is contracted (firing rate increases w/greater tension) |
| dorsal roots carry __ | afferent AP's to CNS via dorsal horn |
| ventral roots carry __ | efferent AP's to effector organs |
| primary somatosensory cortex | proprioceptive and cutaneous information ascends in afferent tracts in spinal cord and projects to sensory and parietal cortex |
| somatotopic organization | amount of cortical tissue devoted to each body surface proportional to sensitivity of that part |
| reflexes | rapid, involuntary, and predictable responses to stimuli |
| reflex arc | direct route from sensory neuron to an effector organ |
| latency | app. 75 ms |
| 4 factors affecting latency | 1. length of pathway 2. # of synapses 3. myelin 4. axon diameter |
| eye movements are controlled in the ___ | brainstem |
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