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POTH 455 > MT1 > Flashcards

MT1 Flashcards

1
Q

3 main functions of the BS?

A

 Conducts all the communication between the brain and SC
 Regulates the level of consciousness (reticular formation)
 Targets or source of the CNs (motor and sensory information to the head and face)

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2
Q

what structures make up the BS?

A

 Midbrain
 PONS
 Medulla

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3
Q

what are the main functions of the medulla?

A

 Important for
• HR, BP, breathing, pressure
• Reflexes: vomiting, sneezing, digestion, balance

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4
Q

what fibers/tracts decussate in the medulla and where?

A

CST in the pyramids

DCML at medial leminiscus

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5
Q

what is the function of the inferior olives? where are they found?

A

• Involved in fine motor control
• Major source of input to the cerebellum from the SC
found in the medulla

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6
Q

what is the pons?

A

 Mass of decussated fibers that cross the midline

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7
Q

what are the main structures found in the pons?

A

pontine nuclei
cerebellar peduncles
mesopontine cholinergic system
locus coeruleus

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8
Q

what is the pontine nuclei? fucntion?

A

• Involved in motor activity and relies information from M1 to cerebellum

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9
Q

what tracts are contained by the cerebellar peduncles?

A

o spinocerebellar tracts (VST,DST, CUNEOCEREBELLAR)

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10
Q

what is the mesopontine cholinergic system involved in?

A

• arousal, attention, learning, rewards, voluntary movement, locomotion

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11
Q

what is the pudunculopontine?

A

ACH projecting cells to the inferior frontal cotex and projects to BS MNs

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12
Q

what system is locus coeruleus part of?

A

reticular system

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13
Q

what biogenic amine is formed in locus coeruleus?

A

NE

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14
Q

what is the main function of locus coeruleus?

A

mediates arousal, emotions, mood, sleep & ANS

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15
Q

what structures form the midbrain?

A 
superior colliculus
inferior colliculus
substancia nigra
red nucleus
cerebellar peduncles
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16
Q

what tract originates from the superior colliculus

A

tectospinal tract

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17
Q

what is mediated by superior colliculus

A

• vision, multisensory integration, ocular movements

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18
Q

what is mediated by the inferior colliculus?

A

auditory system

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19
Q

what biogenic amine is produced by substancia nigra?

A

dopamine

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20
Q

substancia nigra recieves input from where?

A

basal ganglia

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21
Q

what tract originated from the red nucleus?

A

rubrospinal tract

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22
Q

what are the cerebellar peduncles?

A

• massive projections from the cerebral cortex to brainstem and SC targets

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23
Q

where does the reticular formation range from?

A

ranges across the entire brainstem

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24
Q

what are the main functions of the reticular formation?

A
  • Cardiovascular & respiratory digestive controls
  • Sleep & wakefulness regulation
  • Mood (Serotonine)
  • Origin of the reticular spinal tract which is responsible for Limb and trunk movement
  • Relays eye and ear signal to the cerebellum
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25
Q

in what order are the somatic/visceral motor and sensory tracts organized from posterior to anterior?

A

somatic sensory
visceral sensory
visceral motor
somatic motor

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26
Q

what are some consequences associated with CN lesions?

A
  • Vision disturbances
  • Pupil abnormalities
  • Changes in sensation
  • Muscle weakness
  • Hearing problems
  • Vertigo
  • Voice change
  • Difficulty swallowing
  • Speech difficulty
  • Coordination problems
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27
Q

what portion of phinease Gage was affected?

A

frontal lobe

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28
Q

through phinease gage’s accident what function could be attributed to the frontal lobe?

A

personality

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29
Q

how did broadman manage to organize the cortex of the brain

A

using microscope and identifying brain patterns and thickness to associate to specific functions

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30
Q

how many cortical laayers can be found in the neocortex?

A

6

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31
Q

what are the layers of the neocortex?

A

1: neurophils - cortico-cortical information processing
2- small pyramidal cells- cortico-cortical information processing
3 - small pyramidal cells- interhemispheric
4: stellate neurons - local ramifying axxons
5: large pyramidal cells - output leaving cortex
6: large pyramidal cells and other cells - output leaving cortex

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32
Q

what are some of the complex functions associated to the brain?

A

-thoughts and feelings
-language
-memory
-speech
-emotions
etc

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33
Q

what is the function of the primary visual cortex?

A

recieves, integrates and processes visual stimuli

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34
Q

where is the premotor cortex located based on broadman’s areas?

A

6

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35
Q

what is the function of the premotor cortex?

A

programming of motor sequence in response to visual stimuli

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36
Q

what is the main function of amygdla?

A

regulates emotions

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37
Q

what is the main function of the hypothalamus

A

regulation of certain processes involved in homeostasis

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38
Q

what is the main function of motor cortex?

A

sends motor signal to muscles

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39
Q

what is the main function of basal ganglia?

A

induces control of volontary movements

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40
Q

what is the main function of cerebellum?

A

coordination

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41
Q

what is the main function of the posterior partietal cortex?

A

regulates planned movements and spatial resoning

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42
Q

what is the function of the BS nuclei?

A

regulates cardiac and respiratory functions

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43
Q

what is the main function of hippocampus ?

A

storage of memory

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44
Q

what is the main function of the parietal association cortex?

A

mediates attention

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45
Q

what is the main function of the temporal association cortex?

A

identification of stimuli

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46
Q

what is the main function of the frontal association cortex?

A

planning and decision making

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47
Q

what association cortex is associated with extrapersonal/far space?

A

posterior parietal association cortex (area 5& 7)

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48
Q

the posterior parietal association cortex recieves input from where?

A

S1 (3A,3B, 1,2) Visual and auditory system

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49
Q

what is the main function of the posterior parietal association cortex

A

integrates somatic sensory info to form spatial percepts in the extrapersonal space

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50
Q

what happens in the case of a right lesion in the posterior parietal cortex?

A

apraxia

left personal neglect syndrom

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51
Q

what is integrated by the parietal lobe?

A

 Cutaneous maps and other body sensations
 Visual inputs
 Auditory functions

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52
Q

what are the main functions integrated by the temporal lobe?

A
  • recognition of speech
  • detection of sounds signals
  • olfaction
  • memory
  • face recognition
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53
Q

the inability to recognize and identify objects/ shapes/ things is known as? how does this occur?

A

agnosia

caused by lesion in the temporal lobe

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54
Q

the inability to recognize faces is known as?

A

prosopagnosia

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55
Q

whta are the major parts of the frontal lobe

A

premotor, motor and prefrontal cortex

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56
Q

what is controlled by the premotor cortex?

A

limb representation

ability to speak

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57
Q

what are is responsible to comprehension of speech?

A

wernike’s area

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58
Q

what area is association for speech production?

A

broca’s area

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59
Q

a lesion on what side will affect speech and listening?

A

on the left side

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60
Q

what happens in the case of a lesion in the prefrontal cortex?

A
  • loss of memory
  • attention deficity
  • lack of social inhibitions
  • flattening of affect
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61
Q

what is the main function of the occipital lobe?

A

o Primary visual functions
o Visual perception
o Recognition of colors
o Recognition of form

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62
Q

where is the hippocampus located?

A

temporal lobe

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63
Q

what hemisphere is better in organizing and using visuo-spatial stimuli?

A

right

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64
Q

what is the right hemisphere specialized in?

A

recognizes global elements (Whole)

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65
Q

what is the left hemisphere specialized in?

A

manipulates local elements (details/parts)

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66
Q

what hemisphere is better for facial recognition?

A

right hemisphere

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67
Q

how are the DCML path involved in visceral pain

A

visceral pain can travel through it. important in cases of cancer with excruciating pain, lesion to the tract may be done to lose sensation and hence pain

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68
Q

what is the main function of the caudal portion of the nucleus of the solitary tract?

A

integrative center for reflexive control of visceral motor function & relay for visceral sensory info to reach other structures

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69
Q

what is the main function of the rostral portion of the nucleus of the solitary tract?

A

gustatory system

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70
Q

how do General sensory afferents from thoracic and upper abdomen organs + viscera neck and head - enter brainstem

A

directly from the nucleus of the solitary tract

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71
Q

what are the two main roles of sensory control in the ANS?

A
  • movement to movement visceral motor activty
  • informs higher integrative centers of more complex stimulation patterns which can signal potential threatening conditions
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72
Q

what is the function of the myenteric plexus?

A

o controls intrinsic musculature of the gut - peristalsis

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73
Q

what is the function of the submucosal plexus?

A

o Provides chemical monitoring and glandular secretion

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74
Q

how are the neurons in the ENS?

A

intrinsic

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75
Q

does the ENS require VNS and CNS integrity?

A

no

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76
Q

what are the main functions exclusively controled by the SNS?

A

 Sweat glands
 Adrenal medulla (release of Adrenaline/NA)
 Piloerector muscles of the skin
 Most arterial blood vessels

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77
Q

how does the PSNS function?

A

PreG neurons release ACH which activates PostG through NACh receptor. the PostG neurons release ACH to modulate target organ via muscarinic receptor

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78
Q

what are the main functions of the PSNS?

A 
REST AND DIGESTION
	Constricts pupils
	Slows heart rate
	Increases peristalsis of the gut
	Promote voiding of the urine from the bladder
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79
Q

Describe the pre/postG fibers in PSNS?

A

long pre

short post

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80
Q

Describe the pre/postG fibers in SNS?

A

short pre

long post

81
Q

where are the primary and seconday neurons in the PSNS located?

A

pre: BS and SC
post: Ganglia near target organ

82
Q

what is the main fucntion of the SNS?

A

fight or flight
 Pupils dilate and eyelids retract
 Blood vessels of skin and gut constrict
 Piloerection & Bronchodilation
 Heart rate & contractile force increases
 Quiescent digestive and other vegetative functions
 The adrenal medulla is activated to release epinephrine and noradrenaline in bloodstream
 Pancreas releases glucagon

83
Q

how does the SNS function?

A

PreG neurons release ACH which activates PostG through NACh receptor. the PostG neurons release NE to modulate target organ via adrenergic receptors (a, b)

84
Q

where are the pregangliuonic neurons found for SNS?

A

LATERAL HORN (T1-L3)

85
Q

what are the main functions of the hypothalamus?

A

maintains homeostasis

86
Q

what are some functions accomplished by the hypothalamaus

A 
interacts with
o	Blood flow
o	Energy metabolism
o	Reproductive activity
o	Coordination sympathetic & parasympathetic responses
87
Q

what are the 3 components that make up the VNS?

A

SNS
PSNS
ENS

88
Q

what is acute pain?

A

results from an injury and serves as a role of protection, as healing occurs, pain diminished

89
Q

what is chronic pain?

A

persists after healing
can be due to hyperactivation of nociceptors
pain syndrome

90
Q

how does sensory gating function?

A

mechanosensory stimuli enters the dorsal column and activates inhibitory local cells blocking pain afferent

91
Q

what is the aim of enkephalin producing cells?

A

modulate/decrease pain

92
Q

give an example of enkephalin producing cell?

A

canabis

93
Q

how do endogeneous opioids funciton?

A

o Exogenously anti-nociceptive compounds suppress nociceptive neurons in the dorsal horn of the SC (opioid, cannabis)

94
Q

what is allodynia?

A

central sensitization caused by high activity in nociceptive afferents. a non painful stimuli now triggers a nociceptive message?

95
Q

what is hyperalgesia?

A

a result of inflammation and substance P release relsulting from an injury in the aims to promote healing and protection. hence a weak painful stimuli will now be exaggereated and cause greater pain

96
Q

how does referred pain happen?

A

convercence of visceral nociceptors on the same neurons in the dorsal horn as cutaneous nociceptors

97
Q

where in the dorsal horn (what laminae) do c fibers synapse in?

A

1 and 2

98
Q

where in the dorsal horn (what laminae) do Adelta fibers synapse in?

A

1 and 5

99
Q

what type of neurons synapse in lamina 5

A

• Neurons in layer V receive nociceptive and non-nociceptive inputs

100
Q

what modalities other than pain and temperature can be sensed by ALS?

A
  • Non-discriminative touch (in the absence of dorsal columns)
  • Innocuous warm & cold temperature sensations
  • Histamine – itch
  • Slow mechanical sensation – sensual touch
  • Sensors of lactic acid released during muscle contraction
101
Q

where are TRP channels located? what type of channels are these?

A

in DRG

ion channels

102
Q

what is mediated by TRP channels?

A

• They mediate a variety of sensation, pain, hotness, warmth/coldness, different types of tastes, pressures and vision

103
Q

what can be used to differentiate vertebrates and invertebrates?

A

TRP channesl

104
Q

what type of pain is carried by A delta fibers?

A

initial, sharp pain

105
Q

what type of pain is carried by C fibers?

A

longer lasting diffuse second pain

Duller, burning quality

106
Q

how big is the diameter of nociceptors?

A

myelinated 1-5 um

unmyelinated up to 1.5 um

107
Q

under what circumstances does silent noiceptors function?

A

o Only work when sensitized by local inflammation and injury (hyperalgesia)

108
Q

what do polymodal C fibers respond to?

A

o High intensity mechanical, thermal or chemical stimuli

109
Q

what do Adelta 2 fibers respond to

A

o Intense mechanical pressure applied to skin

110
Q

what do Adelta I fibers respond to

A

extreme temperatures >45 or <17

111
Q

a lesion in what area of S1 will cause for Inability to use tactile information to discriminate the size and shape of objects

A

area 2

112
Q

what is the main function of area 2 in S1

A

proprioception andcutaneous

113
Q

a lesion in what area of S1 will cause for Inability to use tactile information to discriminate texture of objet

A

1

114
Q

what is the main function of area 1

A

cutaneous hence responds to pressure and vibration

115
Q

what happens if we have a lesion in area 3B of S1?

A

deficits in all forms of tactile sensation from mechanoreceptors

116
Q

what is the main function of area 3A of S1?

A

proprioception, activated during movements, muscle spindles

117
Q

what is the diameter range of mechanosensory receptors?

A

6-12 um

118
Q

what is the diameter range of muscle spindles??

A

13-20 um

119
Q

what is the main function of rufini corpuscle? RF? rapid/slow adapting cellS? %

A

-slow adapting
Rf ~60 mm2
sensitive to cutaneous stretch during movements
20%

120
Q

what is the main function of pacinian corpuscle?RF? rapid/slow adapting cellS? %

A

rapidly adapting
Rf is the size of finger/hand
sensitive to high frequency vibrations
15%

121
Q

what is the main function of merkel cell? RF? rapid/slow adapting cellS? %

A

rapidly adapting
rf ~22 mm 2
sensitive to low frequency vibration
40%

122
Q

what is the main function of messiner corpuscle? RF? rapid/slow adapting cellS? %

A

slowly adapting
rf= 9 mm2
sensitive to points, edges, curves
25%

123
Q

what is two point discrimination threshold?

A

minimum interstimulus distance required to perceive 2 simultaneous applied stimuli as distinct

124
Q

what happens if we touch center of RF?

A

increases cell firing

125
Q

what happens if we touch surround of RF?

A

decreases cell firing

126
Q

what happens if there is an absence of receptors between two fields

A

discrimination is impossible

127
Q

how can a mechanosensory afferent be transduced?

A

stretch opens cation channel, Na+ influx which depolarizes and causes for AP to be generated thus mechanical stretch is converted to electrical energy

128
Q

what afferent is responsible for conveying information about muscle tension?

A

Ib (golgi tendon)

129
Q

what is the function of II afferent?

A

its a slow adapting cell
provides sustained response about muscle length
conveys information about the static position of the limb

130
Q

what is the function of IA afferent?

A

rapdily adapting cells that are activated by stretching of the muscle. conveys information about velocity and direction of the movement

131
Q

where do pain and temperature fibers decussate?

A

SC

132
Q

where do fibers from proprioception and fine touche decussate (Aa, AB)

A

in the medulla

133
Q

what is the main function of CPG?

A

CPG controls timing and coordination of complex movements

134
Q

what type of reflex is the flexion withdrawl reflex?

A

polysynaptic reflex

135
Q

what is a myopathic disease due to muscle fiber degenerate?

A

muscular dystrophy/DMD

136
Q

what are some neuropatic diseases that arise due to demyelination of axons?

A

MS
GBS
Diabetes

137
Q

what are some neuropatic diseases that arise due to decrease in amount of MNs?

A

polyio

138
Q

what is the main target of ALS neuropathic disease?

A

a-MNs

139
Q

how can spasticity be treated?

A 
PTOT TO RELIEVE CONTRACTURES
physical modalities such as FES
botox
gaba agonists
rhizotomy
140
Q

WHAT IS THE FUNCITON OF THE STRETCH REFLEX?

A

assists in maintaing balance and muscle tone

141
Q

what does the coactivation of a and gamma MNs allow?

A

spindles to function- sends info centrally

• Regulate the gain of stretch reflex so it can operate efficiently at any length

142
Q

Ia interneurons recieve input from?

A

muscle spindles and descending pathways

143
Q

what can be accomplished by Ia interneurons?

A

o Enhance speed and efficiency of movements

o Stiffen the joint for stabilization

144
Q

how can the force in muscles be controled?

A

varies on the type of MN recruited (bigger= more force)

amount fo AP generated (closer AP= accumulation of force)

145
Q

what is the motor unit

A

aMN & the muslce fibers it innervates

146
Q

what was discovered by charles sherrington?

A

• Discovered the stretch reflex and describes the motor unit

147
Q

what is the posterior cord syndrome?

A

o Incomplete lesion
o Often caused by tumors, hernia, (often non-traumatic)
o loss of 2 point discimination and vibration and proprioception at the level below injury

148
Q

what is brown sequad syndrome?

A

o Lesion in the spinal cord which leads to weakness or paralysis on one side of the body (motor) but loss of sensation to pain and temperature on the opposite side and ipsilateral loss of two point discrimination and vibration
o Segmental flaccid paralysis at the level of the lesion and spastic paralysis at the level below
o Often result of stab or gunshot wound

149
Q

what lesion leads to loss of all sensation and motor functions other than the DCML?

A

anterior spinal A syndrome

150
Q

what is affected by the central cord syndrome?

A

o Loss of proprioception and vibration
o Caused by hyperextension of the neck or whiplash or spinal cord compression
o Most often in the cervical region
o Anterior spinal A. bursts causing for hematoma and death of neuronal tissue in the spinal cord
o Tends to affect the UE more than the LE
o Loss of motor, sensory and pain mostly in the arms, along with loss of two point discrimination and vibration on both sides

151
Q

what spinal levels are most affected by partial transections

A

C4,C5,C6

152
Q

what population group is most at risk of traumatic SCI?

A

males ~40yo

153
Q

what are some symptoms associated with complete SCI?

A 
spinal shock
paralysis
loss of sensation
\+ babinski
loss of bladder and bowel control
154
Q

SCI in the cervical region leads to?

A

full/partial tetraplegia

155
Q

SCI in the thoracic region leads to?

A

paraplegia

156
Q

what is more common traumatic or nontraumatic SCI?

A

Ntsci (58%)

157
Q

what is essential for peripheral nerve repair?

A

schwann cells

158
Q

why are peripheral nerve injuries a challenge for rehab?

A
  • long distance
  • disorganized pattern
  • larger and more fasciles
  • tension, crushing and tissue loss is often involved
159
Q

at what speed does the spout grow if it reaches the neurolemma?

A

1-3mm/day

160
Q

under what condition can axons grow back?

A

only if they are still connected to the cell body

161
Q

what is wallerian degeneration?

A

degeneration of axon and myelin sheath using macrophages

162
Q

when does wallerian degeneration happen?

A

generally ~24H of

163
Q

what follows wallerian degeneration?

A

axonal sprouting

164
Q

what are neutrites?

A

the sprouts sent out to reach the neurolemma

165
Q

do we have more myelinate or unmyelinated axons

A

more unmyelinated, they occupy all the surrounds in the fascicles
10:1 ratio

166
Q

what type of axon has the greatest condution velocity?

A

larger diameter axons

167
Q

which MN between alpha and gamma has a greater diameter?

A

Alpha

168
Q

how does AP in myelinated axons?

A

saltatory conduction

169
Q

how does AP propagate?

A
    1. Stimulation (beyond threshold) opens the Na channels. Na enters the cell, which depolarizes the cell (AP)
    1. Depolarization current travels passively and causes further opening of Na channel; therefore the AP propagates down the axon
    1. Upstream, the closing of Na channels is followed by the opening of K+ channels. K+ leaves the cell, which locally terminates the AP.
170
Q

what are opioids?

A 
o	Family of ~20 different molecules
o	Widely distributed in the brain
o	Functions
	Depressant
	Analgesic
	Sexual attraction
171
Q

what functions are regulated by serotonin?

A

o Regulates sleep and wakefulness

o Implicated in emotions, circadian rhythm, state of arousal, feeling of satiety

172
Q

serotonin dysfunction leads to what? how to treat it?

A

o Depression, schizophrenia, Alzheimer’s eating disorders

-SSRI

173
Q

tryptophan produces what biogenic amine?

A

serotonine

174
Q

histidine produces what biogenic amine?

A

histamine

175
Q

tyrosine produces what biogenic amine?

A

NE/E/Dopamine

176
Q

where does histamine originate from

A

hypothalmaus

177
Q

what is the main function of histamine

A

o Mediates attention and arousal

o Involved in the vestibular system (autonomic system)

178
Q

histamine antagonist are useful for?

A

allergic reactions

179
Q

epinephine? origin? projection? function?

A

o From cell bodies in the medulla
o To thalamus and hypothalamus
o Role: regulation of respiration and cardiac function

180
Q

origin and projection of NE?

A

o From Locus Coeruleus in brainstem to entire brain

181
Q

function of NE?

A

o Involved in sleep, attention, feeding behaviors
o Present in ganglion cells in the sympathetic system
o Major role in the visceral motor system (autonomic system)

182
Q

what does amphetamine stimulate?

A

increases norepinephrine levels

183
Q

where is dopamine produced?

A

substancia nigra

184
Q

what is dopamined involved with

A

o In structures involved in control of movement

o Motivation/reward

185
Q

biogenic amines function on what type of receptor?

A

metabotropic

186
Q

what type of NT is GABA?

A

Inhibitory

187
Q

what is gaba derived from? degraded? receptor?

A

derived from glutamate
degraded by glial cell reputake
both receptors

188
Q

function of GABA?

A

 Very common in local circuits interneurons or highly inhibitory system such as cerebellum

189
Q

gaba agonists?

A
  • benzodiazepines, barbiturates
  • Sedatives and anesthetics
  • Management of epilepsy
  • Baclofen which serves as a muscle relaxant in cases of spasticity
190
Q

glutamate

A

excitatory NT, occupies 1/2 synapses in the brain

191
Q

what is glutamate derived from? degraded? receptor?

A

glutamine
glial cell reputake
both receptors

192
Q

function of glutamate?

A

 Involved in cellular mechanisms of learning and memory
 Involved in pain transduction
 Excitotoxicity (secondary cell death)
• Can cause secondary cell death
 General anesthesia decreases glutamate activity (amongst other effects)
• Less excitation

193
Q

ACh?

A

excitatory and inhibitory

194
Q

ach precursor, degraded, receptor?

A

o Precursors: Acetyl Coenzyme A and Choline
o Degraded rapidly by enzyme Acetylcholine Esterase
-Nach and muscarinic

195
Q

what is sarin gas?

A

prevents degradation of ACh which causes death

196
Q

what drug block muscarinic receptors to prevent motion sickness

A

scapolamen

197
Q

what type of receptor is muscarinic ACh receptor? where does it function?

A

metabotropic

brain cells

198
Q

what type of receptor is Nach? where does it function?

A

iontropic

neuromuscular junction

199
Q

how is ACH on muscarinic receptor involved on ANS?

A

In PSNS released by postganglionic fibers thus decreases HR

POTH 455 (6 decks)

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