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Flashcards in Fitzayyy Deck (139):
1

somatosensation

process that conveys info regrind body and itxn with environment
1. mechanoreception
2. thermosensation
3. nociception

2

transduction channel is a member of

transient receptor potential superfamily of ion channels
eg:
thermoreceptors adapt rapidly to temps
mechanoreceptors repsond to deormations
nocicptors respond to _____

3

nociceptors/TRPV1 opens/responds to

heat
protons
vanillinoids

potentiated by prostaglandins = sensitiziation

4

perception of pain is not simply due to activation of nociceptors, but is the outcome of

modulation of both nociceptive and non-nociceptive inputs

5

gate theory of pain

inhibitory interneurons regulate the transmission of ascending nociceptive information at the level of the second order neuron, allowing modulation of the signal

explains phantom limb pain
success of TENS treatment
opioids

6

steady pressure and stretch receptors

flutter and vibration receptors

Merkel and Ruffini
slowly adapting

Meissner's corpuscles and Pacinian corpuscles
rapidly adapting

7

thermoreception:
stimulus
receptor
location
receptive field
adaptation

(high acuity, well localized, rapid adapt)
cold = menthol, warm = capsaicin
free nerve ending
superficial
small RF
rapid adapt

*direcly coupled to ion channel/no 2nd mess)

8

nociception:
stimulus
receptor
location
receptive field
adaptation

(poor acuity, slow adapt)
thermal = heat, mechanical, polymodal chemical = capsaicin, protons
free nerve endings
superifical
small/rapid, large/slow, large/slow

9

think thermoreceptors...

Receptor proteins depend on....

nociceptive or no?

stimulus type, not the anatomy

10

compounds that sensitize the receptor protein, decrease the threshold for activating channel

sensitization causes

5-HT, ATP, PGs, bradykinin

hyperalgesia - increased pain perception from painful stimulus
allodynia - pain from stimulus that doesn't normally cause pain

11

TRP channels

nonspecific cation channels

think TRPV1 and nociception**

12

how test acuity/how well pain is localized

point localaiton vs 2 point discrimination
physical distance where can perceive two stimuli versus one

13

C fibers

unmyelinated
DULL ACHY PAIN
low conduction velocity
small diameter
mechanoreception, thermoreception, SLOW PAIN

14

Abeta fibers

myelinated
large diameter
high conduction velocity
MECHANORECEPTION ONLY*
OW!

15

Adelta fibers

myelinated
medium diameter
medium conduction velocity
mechanoreception, termoreception, FAST PAIN

16

3 types of pain

1. ACUTE NOCICEPTIVE: fast (sharp, pricking), well localized, Abeta OR slow (achy, dull) C fibers, not well localized

2. INFLAMMATORY PAIN: damage or sensitization to receptor or adjacnet damaged cells

3. NEUROPATHIC PAIN: peripheral or central REORGANIZATION of pathway so don't need a nociceptive stimulus to perceive pain

17

referred pain

activation of nociceptors in viscera = perceived as somatosensory problem
so TWO PATHAWYS GOING TO THE BRAIN
brain doesn't know how to interpret

18

nociception is _____
pain is the _____

sensation
perception

19

transduction

stimulus energy (electromagnetic, mechanical or chemical) converted into electrical potentials interpreted by nervous system
1. stimulus
2. accessory strux
3. receptor with transducer protein****ESSENTIAL STEP
4. seomteims: snd mess
5. ion channels open or close
6. membrane pot change = receptor potential***
7. sometimes NT release on 2nd cell
8. AP generation

20

receptor potential is a _______ to a stimulus

graded response

21

adequate stimulus

type* of energy that a receptor responds to under normal conditions

22

stimulus intensity is encoded int wo ways:

1. frequency coding (firing rate increases with increased intensity)
2. population coding (number 1* afferents increases = RECRUITMENT)

23

adaptation

response of a receptor to constant stimulus declines over time
if change in receptor potential occurs:
SLOW = TONIC
RAPIDLY = PHASIC

24

acuity

ability to localize a stimulus
determined by receptive fields size and receptor density

25

lateral inhibition

application of a stimulus to center of the RF excites a central neuron, but a stimulus applied near the edge inhibits it

= shuts off adjacent neurons
= just because detected in receptor, doesn't mean you will perceive it

26

sensory unit

sensory afferent 1* and receptors that define its receptor field

27

TENS: gate theory

an opportunity to shut down the pain system

28

under normal circumstances, not having pain because

1. no stimulus
2. second order inhibitory neuron

29

by stimulating ______ can shut down the pain pathway/gate to pain

stimulating mechanoreceptors*** reactive the inhibitory interneuron to close gate again

30

inhibitory interneurons of gate of pain are releasing

glycine

31

external and middle ears stimulation

sound

32

job of _____ to deal with complex sounds

cochlea

complex sounds can be deconstructed into a series of sin and cosin waves into component frequencies

33

cochlea is linear or nonlinear

nonlinear - get more freq out than put in

34

external ear/pinna susceptible to shearing upon anterior force

cauliflower ear:
force forward shears cartilage of bone > hematoma > stimulation more cartilage growth

35

4 nerves innervate external ear

greater auricular
less occipital
(both off cervical plexus)
auricular branch of CN X (can envoke fainting from ear)
auriculotemporal branch of V3

36

cause of conductive hearing loss

impaction of cerumen into TM

37

two types glands *unique to EAM

1. ceruminous
2. sebaceous of hair follicle

38

tympanic membrane

deepest point: umbo
pars flaccid doesn't move
4 separate tissue layers: EAC, epithelium, connective distress, endothelium, middle ear

39

TM innervated by

1. external surface: anterior and posterior auriculotemporal of V
2. internal surface: tempering branch of IX glossopharyngeal

sense cold, pain, touch

40

vibration of TM causes

malleus and incus to pivot > stapes footplate vibration at the oval window

41

why is air conduction better than bone conduction

the gain in pressure due to the actions of the ossicles from air sounds prevents some of the energy loss inherent in an air/fluid transition

42

middle ear function

determines what IE will hear
minimizes loss of energy that occurs at air/water interface
amplifies force by
1. TM much larger than OW
2. malleus makes lever situation > lever ratio
3. TM buckles: force concentrated at jumbo

*anything that affects this matching will cause CONDUCTIVE HEARING LOSS

43

mass vs. stiffness

mass: heavy, can't vibrate quickly > transmits low
stiffness: think elasticity, volume of air cavity > transmits high

*every substance has an internal impedance that affects its resonance

44

normal hearing range

100Hz - 20KHz

45

hearing loss starts at

25 dBSL (relative)

46

conductive HL

air conduction affected

47

two labyrinths in inner ear

1. bony: contains perilymph
2. membranous: contains endolymph

48

vestibular/ossesous labyrinth projections

1. semicircular (3)
2. cochlea (spiral)
3. vestibular aquaduct
4. cochlear aquaduct (connects perilymph to CSF)

49

membranous labyrinth

completely enclosed
1. cochlear duct: scala media (core of spiral)
2. saccule (has macula)
3. utricle (has macula)
4. endolymphatic duct (ends in endolymphatic sac)
5. ant, post, and lat semicircular canals

50

receptive areas (where hair cells are)

6 total in each ear
1. organ of Corti (HEARING)
2. maculae = otolith organs (saccule and utricle) (BALANCE)
3. cristae ampullaris = semicurcular canals (BALANCE)

51

inner ear innervation

CN VIII
sensory AFF to brainstem from HC (esp type I)
motor EFF from brainstem to HC (esp type II)

4 branches:
1. auditory branch (cochlea)
2. superior vestibular (utricle and SCs)
3. inferior (saccule)
4. posterior (posterior canal)

52

hair cell transduction

1. fxn as mechanoreceptors: have steriocilia on apical surface that have transduction channels that O and C to change receptor potential (with stretch activated channels)

53

type I hair cells

type II hair cells

"true" sensory receptors
90% AFF
EFF go to dendrites of AFF

motor/contractile cell
10% AFF
each 1* many II HC
large, very secure EFF synapse

54

inner ear transduction is DIRECTIONAL:

displacement toward the tallest stereociliar (positive deflection) results in DEPOLARIZATION

55

adaptation definition

adaptation motor

decrease in response of receptor to a continuous stimulus

move SC towards tallest, the anchoring protein on tall slips down, decreases tension, causes channel to close = keeps hyper polarization possible

motor: keeps tension at proper point for response (channel open)

56

semicircular canals detect ______
otolith organs detect ______

SCs detect head rotation (angular acceleration)
OOs detect gravity (linear accleration)

57

cilia type only in vestibular system

kinocilium
adjacent to tallest steriocilia

58

move head, then >

head rotates (HC move) > fluid doesn't move (inertia) > steriocilia deflect (dep or hyp)

head reaches constant velocity > cupula catches up
steriocilia aren't deflecting > no signal

head stops > fluid and cupola keep moving > steriocilia in opposite direction

59

otolith organs responding to gravity

S: away from midline, horizontal
U: toward midline, vertical

*both otoliths responding in all orientations, stimulate one more than the other

60

otoconia

CaCO3 crystals sitting on top of steriocilia to deflect to gravity

61

base of cochlea
apex of cochlea

base encodes high freq
apex encodes low freq

62

3 tubes/scalae

vestibuli and tympani have perilymph
scala media has endolymph

63

two membranes cochlear

BASILAR divides ST from SM
VESTIBULAR divides SV from SM

64

spiral ganglion/auditory nerve is

in the middle of the bony modiolus

65

scala media

1. BM vibrates
2. SG neuron AFF to inner and outer HC
3. stria vascularis generates endolymph and endochoclear potential (K+)

66

shearing force that causes steriocilia to move

BM vibrates and Tectorial membrane doesn't vibrate > creates shearing force

67

dieter cell

underneath OHC contributes to reticular lamine (stability when OHC contracts)

68

pressure wave induces

vibration (starts in base > peaks at some point)

69

sensoriunrual HL

as age, damage to base first = high frequency HL first

70

passive properties

base: elastic, few supporting cells LOW MASS
apex: floppy, lots of supporting cells

*EACH PLACE HAS SPECIFIC COMBO OF MASS AND STIFFNESS > SPECIFIC RESONANCE FREQ

71

OHC contraction >

increase AMP of BM movement > OHCs contract > mechanical transduction > acoustic energy > resonance vibe at particular spot > BM vibrates > OHCs contract

also signal to the brain when BM vibrates: APs generated by IHCs

POSITIVE FEEBACK LOOP

72

OAE

otoacoustic emissions: sound coming from ear, generated by OHC

73

stria vascularis

produces endlymph (high K+) and the endocohlear potential (+80mV)

74

auditory pathways

HCs in cochlea > auditory nerve > cochlear nuclei in brainstem > trapezoid body > superior olivary complex > lateral lemniscus > inferior colliculus > brachium of inferior colliculus > medial geniculate nucleus > internal capsule > primary auidotyr cortex (superior temporal gyrus) = perception

75

acoustic reflex

HCs in cochlea > spiral ganglion/auditory nerve > cochlear nuclei > trapezoid body > superior olivary complex >

1. EFF to HCs in cochlea
2. trigeminal motor nucleus > V3 > tensor tympani in ME
facial motor nucleus > VII > stapedius ME
*STIFFEN, HARDEN TO SOUND = DECREASED SOUND TRANSMISSION

76

extensive ______ connections of auditory system

BILATERAL

77

vestibular pathways

HCs in SC canals and otolith organs > vesibular ganglion/vesibular nerve > vestibular nuclei >

i. medial lemniscus > ventroposterior nucleus of thalamus > internal capsule > vestibular cortex = PERCEPTION

ii. lateral vestibulospinal tract (LVST) > limb and trunk
medial vestibulospinal tract (MVST) > upper back and neck = VESTIBULOSPINAL REFLEXES

iii. inferior cerebellar peduncle > vestibulo-cerebellum/flocculonodular lobe = VESTIBULOCEREBELLAR REFLEXES

iv. medial longitudinal fasciulus (MLF) > 3 motor nuclei:
oculomotor nucleus > CN III > sup, med, inf rectus
abducens nucleus > CN VI > lateral rectus
trochlear nucleus > CN IV > superior oblique
= VESTIBULO-OCULAR REFLEX (VOR)

78

acoustic neuroma impacts

IAM
vestibular CN VIII and facial CN VII
damages acoustic N and facial N and labyrinthine artery > hair cell damage

79

vestibulospinal tract is ______ in cervical SC

ventral column

80

vestibular nuclei found dorsal in _____ section

solitary nuclei and tract found dorsal in _____ section

MLF found _____ in _____ section

cochlear nucleus found dorsal and _____ in _____ section

medulla section

medulla section

MLF found medially in medulla section

dorsal and lateral in medulla section

81

superior vestibular nucleus (SVN) found in ______ in _____ section

superior olivary nucleus (SON) found _____ in _____ section

abducens nucleus found _____ in _____ section

corticospinal tracts found _____ in _____ section

lateral lemniscus is found _____ in _____ section

SVN found in MCP of pons section

SON medial WHITE SPOT in pons

nCN VI medial in pons

in potato of pons

lateral in pons

82

inferior colliculus found in _____ section

SCP decussation found in _____ section

cerebral crus found in _____ section

midbrain section

83

medial geniculate body found in _____ section

rostral midbrain section

84

auditory brainstem responses (ABRs)

evolved potential response
estimate of inner ear function and if central pathway fun is correct
peak and valleys: response of nerve

eg: stimulation > AN > TB trapezoid body > BIC brachium inferior colliculus > 1* aud cortex

85

ability to localize sound tested by

Weber

86

superior olivary nucleus can compare ____ and ___ of both sides ability to localize sound

compares timing and intensity

if alter timing in one ear, can't process where sound is from - change in weber test (sound localizes to one ear)

87

Weber findings

abnormal: sound localizes to one ear
CONDUCTIVE hearing loss, SOUND travels to DAMAGED EAR
SENSORINEURAL hearing loss, SOUND travels to GOOD EAR

88

LVST lateral vestibulospinal tract

MVST medial vestibulospinal tract

AFF: entire labyrinth MOTION AND GRAVITY
lateral vestibular nucleus
POSTURAL CHANGES to compensate for tillts
adjustment of PROXIMAL LIMB AND TRUNK
(contracts extensor muscles, indirect relaxation of flexor muscles)
EFF: IPSILATERAL, excitatory

AFF: SC canals MOTION
medial vestibular nucleus
STABILIZE HEAD POSITION WHEN WALK
relaxation of muscles of upper back and neck
EFF: BILATERAL, "more complicated than ex and in"

89

impt clinical test for brain activity/brain dead

VOR

no "dolls eyes" movement = brain dead

90

VOR

move head in one direction, eyes move in other direction
to compensate for head motion

turn head left > left DEPOLARIZATION > vestibular ganglion > vestibular nuclei > L excitation > IPSILATERAL CN III medial rectus and CONTRALATERAL CN VI lateral rectus

hyperpol and inhibition of others

91

nystagmus

competition between VOR and cortex to where head and eyes should be. defect in vestibular system when spontaneous nystagmus

COWS; name nystagmus by FAST SACCADE: "beating"

92

COWS

cold water: opposite nystagmus (cold water in left ear, right nystagmus)
warm water: same nystagmus (warm water in left ear, left nystagmus

93

nystagmus and lesion locations

lesion in CORTEX: SACCADE eliminated

lesion in BRAINSTEM: NO VOR or SACCADE

94

conductive HL damage

sensorineural HL damage

central auditory processing disorders damage

external or middle ear

HC or auditory N or cochlear

"cocktail party" hearing deficit in CNS, inferior colliculus

95

profound worsening HL at ____ Hz

80Hz

96

normal audiogram

air conduction through ME gives lower thresholds than bone. AC > BC

97

conductive HL

sensorineural HL

bone thresholds normal, air thresholds much higher
(need more sound)
WORSE AIR CONDUCTION THAN BONE CONDUCTION

HL for both AC and BC
bone and air thresholds much higher (especially in higher Hz)

98

Rinne tests for

Weber tests for

conductive loss

lateralization of hearing or HL
unilateral SENSORY loss: localization to normal ear
unilateral CONDUCTIVE loss: localization to affected side

99

tympanometry test

measures ME pressure
fluid in ME
TM perforation
ossicular chain disruption
potency of ventilation tube

100

acoustic reflex test

apply sound and conduct tympanometry test
*HL required to evoke acoustic reflex = middle ear compliance
FACIAL NERVE FXN

101

audiograms test

OAE: ME fxn, COCHLEAR (OHC) FXN

ABR (auditory brainstem response): ME fxn, IE and auditory nerev fxn, AUDITORY PATHWAY FUNCTION

102

intrafusal muscle fibers

NON-contractile
1* (Ia) afferent fibers
2* (II)
INNERVATED BY GAMMA MNs

103

extrafusal muscle fibers innverated by

alpha MNs

104

______ responsible for the stretch reflex.

Muscle spindles

105

stretch reflex 5 steps

1. muscle stretches
2. depolarization in spindle AFFERENT
3. activation of alpha nd gamma MNs
4. contraction of extrfusal and intrafusal muscle fibers
5. maintains tension in spindle to allow it to connive to be response

106

inverse stretch reflex

increased activity of inhibitory interneuron > decrease alpha MN activity > RELAX

107

flaccid paralysis

spastic paralysis

eliminate alpha MNs

overactive gamma MNs

108

reflex arc

1. sensory receptor
2. 1* afferent neuron
3. 1-3 CNS synapses
4. MN
5. muscles

109

recurrent inhibition

afferent neuron or mN shuts itself off

110

absence of descending control of gamma MNs >

clasp knife reflex

111

Perception: complex processing types

1. series processing (labelled line/series carried to cortex)
2. parallel processing (divergence)
3. convergence (within and across modality/gate theory of pain: mechano and noci to SC)

4. descending info down to receptor level

"what you see is not what you get"

112

selective attention

cortex decides what it wants to perceive
posterior parietal selective attention?

113

ganglion cells and lateral inhibition by ______

horizontal and amercing cells are responsible for lateral inhibition

result > ganglion cells have increased response to contrast; generate a definitive response

114

key step to integrate PRs response and generate APs in ganglion cells:

response of BIPOLAR CELLS
some don't chang signal, some flip signal so is off, depends = complex ganglion cell response

115

ganglion cells

primary visual cortex

on and off cells

orientation
then orientation and motion

= DORSAL STREAM: WHERE

116

visual cortex physiology:
1st dimension
2nd dimension
3rd dimension

1st: OCULAR DOMINANCE > depth perception
2nd: ORIENTATION: edges and motion
3rd: COLOR in "blob" regions

117

_____ is overrepresented within primary visual cortex input = ocular dominance

fovea

118

strabismus

muscle imbalance results in misalignment of visual axes of two eyes > causes DIPLOPIA

119

amblyopia

suppresses info from weaker one eye (cortex coping), so decreased visual acuity
permanent

120

80% of ganglion cells encode _____ (color perception)

encode L/M wave: red green differences

121

difference in acuity depends on

contribution of cone types because RFs are different sizes

122

luminescence (wavelengths)

long and medium (L + M) wavelengths, red and green codes encoding = CONTRAST

123

outputs from visual cortex

dorsal and ventral streams

ventral stream: "WHAT" encodes COLOR AND FORM
dorsal stream: "WHERE" encodes MOTION AND DEPTH PERCEPTION

124

corticoacromotopsia

can't see color or id things
(ventral stream/color and form issue)

125

ideomotor apraxia

can't execute movements dependent on site
(dorsal stream/motion and depth perception issue)

126

language processing (general process)

1. comprehension (input)
LISTENING (starts in auditory)/READING (starts in visual)

2. interpretation of language

3. expression (output)
SPEAKING (vocal apparatus muscles)/WRITING (hand muscles)

127

what defines a language

grammar (symbols)
syntax (contex)
prosody (conveys meaning)

128

primary language pathway

input from primary visual and auditory cortex > LANGUAGE COMPREHENSION in Wernicke's area in posterior temporal lobe > arcuate fasciculus > MEANINGFUL LANGUAGE FORMED in Broca's area in posterior inferior frontal lobe > primary motor cortex > voluntary muscles > speech

129

Gershwind's territory

receives input from primary visual and auditory cortex > RECOGNIZE AND LABELS ITEMS > synapse on Wernicke and Broca's areas

not developed until 5/6 years old (so can read)

130

Lateralization

LEFT (dominant) cortex: RIGHT VISUAL FIELD processing
RIGHT cortex: LEFT VISUAL FIELD processing

= lateralization through corpus collosum

131

another lateralization example

PROSODY (emotion of speech) COMPREHENSION and INTERPRETATION in RIGHT cortex > thru corpus colosseum (?) > LEFT cortex: WRITING and SPEECH COMPREHENSION > L + R 1* motor cortices > output

132

handedness stats

90% right handed, 10% left handed

LANGUAGE localized in L cortex and
EMOTIONAL CONTENT in R cortex:
true in 95% of RH people and 60% of LH people
(of 20% bilateral, 20% are R cortex dominant)

133

vocalization = tonal qualities of speech (steps)

1. airstream from lungs
2. vibration of vocal folds
3. filtering by vocal tract (vowels/shape of vocal tracts and consonants is opening and closing folds)
4. output sound

134

phonomes

speech sounds
200 phonomes > syllable > words > sentences

10,000 words in active (average) vocabulary

135

aphagias definition/general types

speech disorders
impaired language without affecting other cognitive fxns
***impairment in ability to sue or comprehend words***

1. FLUENT can generate words, can't comprehend
2. NON-FLUENT can comprehend, can't generate words

136

aphasias/dyphasias (4)

1. RECEPTIVE dysphasia:
WERNICKES
severe deficit in auditory and written COMPREHENSION
FLUENT (many words, but is nonsense)

2. CONDUCTION dysphasia:
ARCUATE FASCICULUS
good comprehension, pauses and gaps to figure out words
FLUENT

GERSHWIND area
inability to COME UP WITH CORRECT WORDS

3. EXPRESSIVE dysphasia:
BROCA'S
inability to GENERATE MOTOR CONTROL PATTERN
know what want to say but can't, extremely frustrating
NON-FLUENT

4. GLOBAL aphasia
profound deficits in both COMPREHENSION and EXPRESSION
entire language pathway disrupted/large areas of damage

137

aprosody

inability to COMPREHEND or EXPRESS MEANING of EMOTIONAL EMPHASIS*

138

apraxia of speech

difficulty initating and executing voluntary movement patterns necessary to produce speech when NO PARAYLSIS/WEAKOF SPEECH MUSCLES
= PLANNING/PROGRAMMING PROBLEM
can generate words, can't output
kids

139

dysarthrias

disruption of motor/musclar control due to lesions in CNS/PNS
CNS -X-> muscle
= neuromotor disorder