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Flashcards

phys lab 3130z

Mary Nguyen English 86 cards

Cards in this deck (86)

  1. 1efferent v afferent nervesefferent = spinal cord to periphery
    afferent = periphery to spinal cord
  2. 2intracellular v extracellular nerveintracellular = AP from single nerve fiber = 70-90mV, is + going
    extracellular = a CAP, 5- 10 mV and is -ve going
  3. 3factors affecting differences in threshold and conduction velocitysize and myelination
  4. 4fast nerve fiber diameterlarge diameter
  5. 5why would the CAP no longer inc past maximalall A alpha fibres are excited already
  6. 6why are small diameter neurons more easily excited than large diameter neurons in vivob/c they have greater resistance and a greater voltage depolarization force (current is constant)
  7. 7when does muscular tetany happenwhen ATP dependent transporters d/n permit relaxation b/w contractions -- exhibit saturation kinetics
  8. 8requirements for a hypothesis1. suggested explanation for a phenomenon
    2. used as a basis for scientific investigation
    3. falsifiable
    4. cannot be proved but can be supported
  9. 9paired t test v t test powerpaired t test has greater power b/c reduce noise -- groups are more similar w respect to measurement error
  10. 10what does p<0.05 mean5/100 observed results would be due to chance
  11. 11what is the purpose (2) of stretch reflex- provides body w 1st line of defence against unexpected perturbations which move joints and stretch muscles
    - contributes to posture (resist muscle stretch when standing)
  12. 12process of stretch reflex1. stretch extensor spindles
    2. AP in 1a afferents (annulospiral) from extensor muscle
    3. depolarization of extensor motorneurons
    4. AP in efferent alpha motor neurons
    5. contraction of flexor
  13. 13will EPSP summate to produce AP w (tendon tap, slow muscle stretch, medium muscle stretch)EPSP will summate to produce AP only w tendon tap
  14. 14how fast is the stretch reflex30 ms (compared to 150 ms for voluntary)
  15. 15what is an EMGrecording of extracellular current flow assoc w AP in skeletal muscle (extrafusal muscle fibres)
  16. 16how much of the spinal stretch is due to synaptic and NMJ delay?synaptic and NMJ delay each take about 1 ms
  17. 17what is the reaction time for a cutaneous stimulation?>150 ms (shorter for arm muscles b/c less conduction distance) -- info will go to cerebral cortex
  18. 18muscle spindles provide information about ____length and velocity of muscle stretch
  19. 19proprioception information is available to 3 things:spinal cord, cerebral cortex (somatosensory/posterior parietal) and cerebellum
  20. 20what happens when you vibrate biceps tendonbelieve that the muscle is more stretched (extended) than it really is
  21. 21what happens when you vibrate tricepssubjects attempt to touch nose and experience their hand is passing thru their head
  22. 22how does information get to posterior parietal cortexinfo from spindles thru DCML to somatosensory cortex and then to posterior parietal cortex
  23. 23what happens when you get a lesion to the right posterior parietallose sense of left side of body, will ignore left side
  24. 24which fiber is responsible for the illusion that a vibrated muscle is more stretched than it really isgroup 1A afferents that innervate the annulospinal muscle spindle endings
  25. 253 systems that control balancevision (optokinetic), vestibular, proprioceptive
  26. 26is the optokinetic system voluntary or involuntaryit is involuntary. the optokinetic system does not involve the visual cortex.
  27. 27optokinetic systemassumes visual world is stationary (if visual field moves it's cause u moved). involves input from retina to vestibular nuclei -- d/n involve visual processing by visual cortex
  28. 28what happens to optkinetic system if, when standing, one sways to the rightthe visual field will move to the left -- generates automatic optokinetic response by means of the vestibular nuclei which moves the head and body to the left to compensate for the left sway
  29. 29in a situation where balancing is hard, can a subject balance accurately if their eyes are shut?no it gets harder
  30. 30in a situation where balancing is hard, what is the effect of moving the visual world to the left, right, forwards/bkwdsubject will move in the direction of movement of the visual environment. movement of the visual world to the left is perceived as if the subject is moving to the right so the subject moves to the left to compensate
  31. 31location and 3 major fns of vestibular apparatuslocated in inner ear: 3 major fns: eqm, vestibular postural reflexes, vestibular ocular
  32. 32utricalhorizontal constant acceleration
  33. 33sacculevertical constant acceleration
  34. 34semicircular canalsdo not provide information about statics (that's why you don't feel the world rotating)
  35. 35if a subject is being rotated to their right at a constant velocity and is suddenly stopped what happens to eye movementsduring maintained rotation, fluid in semicircular canals becomes stationary and no eye movements occur. If rotation is stopped suddenly, the head stops but endolymph keeps moving and produces an artificial COR and nystagmus (VOR + return saccades). nystagmus will be in the opposite direction to that occurring initially --> when subject opens eyes, will experience that the visual world is undergoing jerky movements to the LEFT (bc VOR is to the right)
  36. 36what is the effect of vision on nystagmusvision can suppress vestibular nystagmus-- demonstrates cerebellar learning
  37. 37if someone is rotated to the right at a constant v, then undergo angular deceleration... they are asked then, after stopping, to point their arm at a stationary target in front of them. What happens to the arm?pressure on cupula is opposite to that exerted @ the start of rotation so the subject feels they are rotating to the left even tho they are stationary. they then voluntarily move their arm to the right to keep pointing at the target.
  38. 38is this arm movement a reflex?no it is a voluntary compensatory arm movement in response to the conscious sensation of self motion to the left -- it is not a vestibular postural reflex
  39. 39evidence that this is not a vestibular postural reflexwhen they're told to point in the direction that the body is facing, the arm movement does not occur
  40. 40effect of grounding on sensation of self turningsuppresses self turning
  41. 41features of cerebellar gait ataxiaveering, stumbling path w irregular and variable foot placement and stride length
  42. 42what is the effect of heel-to-toe gait when the subject looks at their feet v when the subject looks @ a distant objectthey will show gait ataxia -- occurs due to conflict about body/leg position in space b/w the normal vestibular and proprioceptive information and the abnormal visual information. if looking ahead, will walk in fairly coordinated fashion at 30 degrees to the straight line (no abnormal visual info about leg position)
  43. 43saccadesinvoluntary and voluntary! 900 degrees/sec. vision blocked during saccade.
  44. 44prosaccade vs antisaccadeprosaccade = stimulus to right, saccade to the right
    antisaccade: stimuus
  45. 45smooth pursuitconjugate movements which occur when tracking a moving object. purpose is to keep image of moving object on the fovea.
  46. 46what happens when you try to make a smooth pursuit but there's no object thereget a series of saccades instead
  47. 47speed of smooth pursuit v saccades100 degrees/s v 900 degrees/s (smooth pursuit a lot slower)
  48. 48apart from speed, what other factors affect smooth pursuitalcohol and lesions of medial cerebellum, drugs, fatigue, distraction
  49. 49can subjects continue smooth pursuit in the absence of a moving objectyes this can occur when vision of the moving object is blocked (ie object goes behind a barrier) for a short time -- inc time of target disappearance leads to breakdown in smooth pursuit and its replacement of saccades
  50. 50EEGelectroencephalogram is a recording of electrical activity of the brain made by electrodes attached to the scalp. It results from the summation of electrical currents assoc w cortical EPSPS and IPSPs
  51. 51delta waves0-4 Hz
  52. 52theta waves4-8 Hz
  53. 53alpha waves8-13 Hz
  54. 54beta waves13-30 Hz
  55. 55gamma waves30-100 Hz
  56. 56alpha rhythmlarge EEG detected at electrodes over occipital cortex. is not apparent when eyes are open. synchronized, with frequency 8 -13 Hz
  57. 57what do waves look like when eyes openbeta rhythm of low amplitude, aka "desynchronized EEG"
  58. 58what do waves look like during slow wave or non rapid eye movement (NREM) sleepslow EEG of high amplitude @ delta frequency range
  59. 59describe the effect on frequency and amplitude of the EEG trace recorded from the occipital cortex when a) performing mental arithmetic (eyes closed) b) opening eyesboth will produce alpha block -- desynchronized, high frequency (beta rhythm) of 13-30 Hz, low amplitude
  60. 60describe the EEG pattern assoc w the 4th stage of nonREM sleep v REM sleepa) last stage of NREM is deep sleep -- get strong synchronization, large amplitude slow waves, that occur 0-4 Hz (delta)
    b) REM (paradoxical sleep) -- EEG is desynchronized and resembles the awake EEG
  61. 61what is an evoked potentialelectrical events that occur simultaneously in thousands of cortical neurons after stimulation of a sense organ -- can be recorded by electrodes on skull
  62. 62what is the origin of electrical currents assoc w the somatosensory primary evoked potentialcome from extracellular currents due to synchronous postsynaptic potentials (IPSP, EPSP) in cortical neurons. The primary evoked potential is a result of excitation (depol of cell bodies) in deep cortical layers
  63. 63Why is the visual evoked potential of longer latency (100ms) than somatosensory evoked potential even tho the latter has a further distance it needs to travellong time for visual stimulus to be processed in the retina due to second messenger cascade
  64. 64why is a checkerboard pattern an effective visual stimulushas both: high contrast, straight edge image
  65. 65why do we take an average when we're recording for visual evoked potentialelectrical currents on skull are very small and in any one trial are overwhelmed by noise... averaging cancels out the noise and thereby improves the signal to noise ratio
  66. 66what happens in the 20-30 throws after the subject puts on the fresnal lensesprogressively throw closer to the aimed target
  67. 67recalibration in a patient w cerebellar lesiondoes not occur, or occurs very slowly in a patient w a cerebellar lesion
  68. 68if the subject then removes the lenses they will usually throw to the right -- why is this?the motor system has remained recalibrated and throwing to the right is called a negative after effect -- evidence that learning has taken place
  69. 69where does learning take place for throwing errorthrowing error is detected by visual feedback to the inferior olive which causes the climbing fibre (teacher) to produce a change in the modifiable synapse (b/w parallel fibres and purkinje cells)
  70. 70will the left arm be recalibrated for overarm throwing?no-- after right arm overarm throwing, neither the left arm overarm throwing or the right arm underarm throwing will be recalibrated
  71. 71what is a receptive fieldarea on the surface of the skin upon which application of the receptor's adequate stimulus will activate the receptor ... size varies from one receptor to another. (thermal has punctate and pacinian have large)
  72. 72how is stimulus duration encoded in the discharge pattern of receptor neurons?adaptation occurs when a stimulus persists for a long time and the perceived intensity diminishes
  73. 73adaptation for pacinianFAST adaptation
  74. 74adaptation for merkel'sSLOW adaptation
  75. 75if eyes open and person knows the ball is heavy, does EMG activity occur before or after ball hits handEMG activity in biceps muscle occurs up to 120 ms before the ball hits the hand which demonstrates that this is an anticipatory response -- may also occur after ball hit and contain a component due to stretch reflex activity
  76. 76what would occur if the ball was dropped onto the outstretched arm of a blindfolded subjectanticipatory EMG is absent and EMG assoc w stretch reflex and voluntary rxns are present
  77. 77can patients w lesions in the cerebellum adjust their anticipatory EMG activity when going form a light to heavy ball?no they're unable to inc the anticipatory muscle activity across the muscles involved -- unable to adapt to the new ball
  78. 78humans can localize sound in the left to right direction w an accuracy as low as _ degree of arc1 degree
  79. 792 mechanisms that allow humans to localize sound1. interaural intensity differences (for freuqencies above 3 kHz)
    2. intraaural time differences (for frequencies above 3kHz)
  80. 80localizing sound in the median planeup, down, front, behind, 2 above mechanisms are not enough. in this case, additional cues come from the filtering effects of the pinnae (external ears) and the external ear canals.
  81. 812 features of auditory pathway assoc w sound localization1. crossing over of auditory information (axons from each cochlea nuc go to both ipsilateral and contralateral superior olive)
    2. parallel transmission of auditory information (pathways on both sides of the brainstem relay auditory info from both ears to the cortex)
  82. 82which CNS auditory structures are involved in sound localizationall CNS structures, including auditory cortex....
  83. 83what happens when you change the oritentation of the pinnaedramatic deterioration occurs in ability to localize sound in the medial plane
  84. 84if you have 2 groups (control, treatment)if use same subjects use paired t test ... if diff subjects use unpaired t test
  85. 85if have 3 or more groupsuse repeated measures ANOVA (if same subjects) and ANOVA if diff subjects
  86. 86when is something highly significantp<0.001

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Flashcards on phys lab 3130z, created by Mary Nguyen on 08/12/2015.
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