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Flashcards in Neuro Physiology Deck (207)
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1
Q

What are the 3 levels of functional hierarchy observed in motor control?

A

Strategy - basal ganglia
Tactics - motor cortex & cerebellum
Execution - brainstem & spinal cord

2
Q

What do lateral spinal pathway control?

A

Voluntary movements of distal muscles

3
Q

What do ventromedial spinal pathways control?

A

Control posture & locomotion

4
Q

Where does the CS tract cross over?

A

Medulla

5
Q

What does the right motor cortex control?

A

Left side (motor control)

6
Q

Where do CST neurons synapse?

A

Ventral horn

7
Q

Where does the Rubrospinal tract originate?

A

Red nucleus (midbrain)

8
Q

If a lesion of CST or RST occurs what will be observed?

A

Fine movements of hands & arms lost

9
Q

If the CST alone is lesioned what will be observed?

A

Some deficits seen however function will reappear after a few months

10
Q

What is the Brodmanns area associated with motor control?

A

Area 4

11
Q

What are the 2 ventromedial pathways called?

A

Vestibulospinal
Tectospinal tracts
Reticulospinal tract

12
Q

What is the vestibulospinal tract responsible for?

A

Stabilises head & neck

13
Q

What is the tectospinal tract responsible for?

A

Ensures eyes remain stable as body moves

14
Q

Where do the reticulospinal tracts originate?

A

Brainstem

15
Q

What is the function of the reticulospinal tracts?

A

Maintains balance & body posture

16
Q

What muscles does the reticulospinal tract activate?

A

Trunk muscles

Antigravity muscles

17
Q

Where are LMNs found?

A

Ventral horn of spinal cord

18
Q

Medial motorneurones will control which muscles?

A

Axial & proximal limb muscles

19
Q

Lateral motor neurones will control which muscles?

A

Distal limb muscles

20
Q

What is another name for he primary motor cortex?

A

Pre-central gyrus

21
Q

What lies in front of the primary motor cortex?

A

Pre-motor cortex (PMA)

22
Q

Stimulating the right primary motor cortex will result in what?

A

Twitching of right limb

23
Q

What inputs to the posterior parietal cortex allow knowledge of body in space?

A

Somatosensory
Proprioceptive
Visual

24
Q

Axons from which 2 brain areas converge on Area 6?

A

Prefrontal cortex

Posterior Parietal cortex

25
Q

If you only think about carrying out a movement, which are of the brain will become active?

A

Area 6 - pre-motor cortex

26
Q

What is Area 6 responsible for?

A

Encodes decried actions and converts this int how to carry them out

27
Q

Where will neuronal stimulation be identified just before a planned movement takes place?

A

PMA - Premotor cortex

28
Q

In order to perform precise movements, what firing of Abs will be observed in Area 4?

A

Integrated activity of large population of neurones in M1 will produce precise movements

29
Q

What symptoms/signs will be observed with cortical damage?

A
Contralateral flaccidity 
Hyperreflexia
Babinski reflex - extension
Spasticity 
Clonus
30
Q

Describe the loop of information from cortex to basal ganglia

A

Inputs will move from cortex > thalamus > basal ganglia and back to SMA (AREA 6)

31
Q

What is the corpus striatum? Role?

A

Caudate nucleus & putamen

Input zones of basal ganglia

32
Q

What is the corticstriatal pathway?

A

Inputs running from the cortex to the basal ganglia

33
Q

In Parkinsons disease, which area of the brain is affected?

A

Substantia niagra degeneration (dopaminergic neurons)

34
Q

What are some of the classical signs of Parkinsons disease?

A

Slowness in voluntary movements
Increase muscle tone
Tremors in hands

35
Q

What is observed in the brain of someone with Huntingtons disease?

A

Profound loss of caudate, putamen & globes pallidus (inhibitory basal ganglia)

36
Q

What are some of the signs associated with Huntingtons disease?

A

Hyperkinesia - chorea
Dementia
Personality disorder

37
Q

What is chorea?

A

Spontaneous, uncontrolled rapid flicks & movements

38
Q

A lesion in the cerebellum will result in what?

A

Uncoordinated movements = Ataxia

39
Q

Where do preganglionic sympathetic nerves synapse?

A

Sympathetic chain

40
Q

What cranial nerves have parasympathetic innervation?

A

3,7,9,10

41
Q

In the sympathetic system, the NT released from the preganglionic is ____ and acts on_____ receptors.

A

Ach

Nicotinic

42
Q

In the parasympathetic system, the NT released from the preganglionic is ____ and acts on_____ receptors.

A

Ach

Nicotinic

43
Q

In parasympathetic system, what NT is released from postganglionic fibres ____ and acts on _____ receptors.

A

Ach

Muscarinic

44
Q

In sympathetic system, what NT is released from postganglionic fibres ____ and acts on _____ receptors.

A

Noradrenalin

Adrenergic

45
Q

At the adrenal medulla, what stimulates release of adrenalin?

A

Sympathetic postganglionic fibres

46
Q

In the eye, sympathetic activation causes what?

A

Contracts radial muscle = pupillary dilation

Relaxtion of ciliary body = focusses far away

47
Q

B2 adrenergic receptors usually stimulate_____.

A

Relaxation

48
Q

Alpha 1 adrenergic receptors usually stimulate ______.

A

Contraction

49
Q

In parasympathetic activation, what happens to the eye?

A

Contraction of sphincter muscle = pupillary constriction

Ciliary body contraction = lens focusses close up

50
Q

Eye drops used to dilate the eye may contain ______ or ______.

A

Alpha 1 agonist

Muscarinic antagonist

51
Q

In blood vessels, sympathetic innervation can cause _____ or _____

A

Vasconstriction (A1) or vasodilation (B2)

52
Q

Where in the body can the sympathetic system cause vasodilation?

A

Skeletal muscle

Cardiac muscle

53
Q

In the respiratory system, sympathetic stimulation will result in _____.

A

Relaxation of smooth muscle

54
Q

What will happen in the Valsalva manoeuvre?

A

Sympathetic stimulation will increase HR & SV as a result of decrease in venous return during breath hold

55
Q

What are the different types specific sensory receptor types which measure different modalities of sensation?

A
Nociceptors
Chemoreceptors
Mechanoreceptors
Thermoreceptors
Proprioceptors
56
Q

When a stimulus is sensed, what is the name of the potential that is transduce?

A

Receptor (generator) potential

57
Q

The size of the ______ encodes the intensity of stimulus.

A

Generator potential - graded potential

58
Q

The frequency of _____ encodes the intensity of stimulus.

A

Action potential

59
Q

What does the receptive field encode?

A

The location of the stimulus

60
Q

Which test can be done to assess the size of receptive field?

A

2 point discrimination tests

61
Q

What are the 3 primary afferent cutaneous sensory fibres?

A

Ab
Ao
C

62
Q

Which is the fastest sensory afferent?

A

Ab (large myelinated fibres)

63
Q

Which is the slowest sensory afferent?

A

C (unmyelinated fibres)

64
Q

What types of sensation do Ab fibres carry?

A

Touch
Pressure
Vibration

65
Q

What types of sensation do Ao fibres carry?

A

Fast pain
Cold
Pressure

66
Q

What types of sensation do C fibres carry?

A

Slow pain

Warmth

67
Q

What sensory afferents carry information about proprioception?

A

Ab

Aa

68
Q

In which spinal column do Ab & Aa fibres go up?

A

Ipsilateral dorsal column (carrying mechanoreceptor/ proprioceptive info)

69
Q

In which spinal column do C & Ao fibres ascend?

A

Contralateral spinothalamic tracts

70
Q

How many neurones are present in ascending tract?

A

3

71
Q

If damage occurs to dorsal column what will be observed?

A

Loss of pressure, touch, vibration of same side

72
Q

If damage occurs to the anterolateral column of spinal cord what will be observed?

A

Loss of pain sensation on opposite side

73
Q

Convergence will result in _____ acuity

A

Reduced

74
Q

What allow for better definition of boundaries in a receptor field?

A

Lateral inhibition

75
Q

What enables sensory receptors to alter firing in response to sustained stimulus?

A

Adaption

76
Q

What are the different types of pain which can be perceived?

A
Sharp stabbing 
Dull, diffuse throbbing 
Visceral pain 
Referred main 
Phantom limb pain
77
Q

What fibres would be responsible for fast stabbing pain?

A

Ao fibres

78
Q

Which fibres would be responsible for slow dull pain?

A

C fibres

79
Q

Which chemical mediators can activate nociceptive response at the nerve terminal?

A

Bradykinin
Prostaglandin
Histamine

80
Q

Which channel do opiates mediate their action at the nerve terminal?

A

K channels - hyper polarise cell therefore inhibit signal transduction

81
Q

Where do Ao/C fibres synapse?

A

Dorsal horn

82
Q

What mediates Gate control theory?

A

Inhibitory interneuron

Descending inhibitory pathways

83
Q

What 2 ways can the inhibitory interneuron be activated ?

A

By Ab fibres - rubbing it better (mechanoreceptors)

Descending pathways

84
Q

How does the inhibitory interneuron close the gate at the dorsal horn?

A

Releases opiate peptides which inhibit synaptic release

85
Q

What is another name for opiate peptides?

A

Endorphins

86
Q

Where in the brain do descending pathways come from to close the gate?

A

PAG

NRM

87
Q

What does prostaglandin do at the sensory nerve terminal?

A

PGN sensitises nociceptors to bradykinin

88
Q

How do NSAIDs mediate their action?

A

Reduce PGN being produced therefore reduce the sensitisation of nerve terminal to bradykinin

89
Q

How do TENS machines work?

A

Stimulate Ab fibres therefore activating inhibitory interneuron, reducing synaptic transmission

90
Q

How does morphine mediate pain relief?

A

Reduces nociceptive sensitivity
Blocks synaptic transmission at dorsal horn (epidural)
Activates descending pathways

91
Q

How do local anaeasthetics block pain transmission?

A

Block Na APs therefore all axonal transmission

92
Q

Where do 2nd order neurons in the spinothalamic tract synapse?

A

Thalamus

93
Q

Where do 3rd order neurons from the thalamus convey to?

A

Somatosensory cortex
Cingulate gyrus
Limbic system

94
Q

Where does pain perception occur?

A

Somatosensory cortex

95
Q

Descending pathways from the ____ radiate to the _____ which decrease pain signals.

A

Peri-aquaductal grey

Dorsal horn

96
Q

What is hyperalgesia?

A

Exaggerated response to pain from normal stimuli

97
Q

What is allodynia?

A

Decreased threshold for pain response

98
Q

What are the 3 components of central sensitisation to pain?

A

Wind-up
Classical
Long term potentiation

99
Q

How does wind-up central sensitisation mediate action?

A

Increases release of NT therefore increased response of neurons

100
Q

How does CLASSICAL central sensitisation mediate action?

A

activates new synapses in the dorsal horn resulting in increased perceptive of noxious stimuli, lasts longer than original stimuli

101
Q

How does long term potentiation central sensitisation mediate action?

A

Incorporates more receptors on post-synaptic side therefore increased response perceived

102
Q

How long does acute pain last for?

A

1 month & resolves with healing of tissue damage

103
Q

How long does chronic pain last?

A

> 3-6 months, lasting longer than duration of healing

104
Q

Which type of pain is protective?

A

Acute

105
Q

What type of pain is associated with acute pain?

A

Nociceptive pain

106
Q

What type of pain is associated with poorly localised presentation?

A

Neuropathic

107
Q

What is pain?

A

A sensory perception of the mind (not a stimulus)

108
Q

What is cognition?

A

Highest brain function

Integration of all sensory information to make sense of situation

109
Q

What are the 3 components of learning & memory?

A

Hippocampus
Thalamux
Cortex

110
Q

What does the hippocampus do in memory?

A

Formation of memory

111
Q

What part does the cortex have in memory formation?

A

Stores memory

112
Q

What part does the thalamus play in memory formation?

A

Searches & accesses memory

113
Q

What areas compose the limbic system?

A

Hypothalamus
Hippocampus
Cingulate gyrus
Amygdala

114
Q

What areas in the limbic system are central to learning?

A

Punishment

Reward areas

115
Q

If damage occurs to hippocampus, what will happen to memory?

A

Intact immediate & long term memory however unable to form new memories

116
Q

What are the different types of memory?

A

Immediate (sensory) memory
Short-term memory
Immediate long term
Long term memory

117
Q

Which type of memory is described as working memory?

A

Short term memory

118
Q

Which the of memory is associated with electrical excitation of reverberating circuits?

A

Short term memory

119
Q

If the memory in the reverberating circuit is deemed significant what will happen next?

A

Consolidated and stored in long term memory

120
Q

If the reverberating circuit is disrupted eg head trauma and the hippo/thalamus is damaged what can occur?

A

Amnesia

121
Q

What are the 2 forms of amnesia?

A

Anterograde

Retrograde

122
Q

What will anterograde amnesia result in?

A

Inability to form new memories

123
Q

What will retrograde amnesia result in?

A

Inability to retrieve old memories

124
Q

What is intermediate long term memory dependant on?

A

Chemical changes at the presynaptic neuron

125
Q

What is long term memory (LTM) dependant on?

A

Structural changes at the synapse

126
Q

What structural changes occur at the synapse in formation of LTM?

A

Increase in NT release sites

Increase in vesicle & NT stored on pre-synpatic side

Increase in number of presynaptic terminals

127
Q

What is another term for strengthening of the synapse observed in LTM?

A

Long term potentiation

128
Q

What are the 2 types of LTM?

A

Declarative

Procedural

129
Q

What is declarative LTM?

A

The ability to recall events (episodic) & language (semantic memory)

130
Q

What is procedural LTM?

A

Often acquired through repetition, includes motor memory skills eg paying tennis, driving etc

131
Q

How can short term memories be converted to LTM?

A

Consolidation (strengthening of synaptic connections by repetition)

132
Q

What composes the Papez circuit?

A

Hippocampus
Mammillary bodies
Anterior thalamus
Cingulate gyrus

133
Q

What is the definition of sleep?

A

A state of unconsciousness from which a person can be aroused by normal stimuli

134
Q

What chemical is the precursor for melatonin?

A

Serotonin

135
Q

If there is a deficiency in serotonin, what will be observed?

A

Inability to sleep

136
Q

Where is melatonin produced?

A

Pineal glands

137
Q

What structure in the hypothalamus is thought to contribute to sleep induction?

A

Suprachiasmatic nuclei (SCN)

138
Q

What does activity of the SCN in the hypothalamus stimulate?

A

Release of melatonin

139
Q

What is the name of the excitatory NT released from the hypothalamus which is required for wakefulness?

A

Orexin

140
Q

If defective orexin signalling is present, what condition is observed?

A

Narcolepsy (inability to stay awake)

141
Q

Where is the main sleep centre of the brain?

A

Reticular formation

142
Q

What does EEG stand for?

A

ElectroEncepheloGram -assess neuronal activity

143
Q

What are the 4 different types of wave pattern observed in EEG recordings?

A

Alpha
Beta
Theta
Delta

144
Q

What EEG waves are associated with awake, relaxed?

A

alpha waves (^ are, ^ amplitude)

145
Q

What EEG waves are associated with being awake & alert?

A

Beta waves (^ freq, low amplitude)

146
Q

What EEG waves are associated with children and stress in adult?

A

Theta waves (Low freq)

147
Q

What EEG waves are associated with deep sleep?

A

Delta waves (low freq, high amplitude)

148
Q

How many stages of sleep are present in the sleep cycle?

A

5

149
Q

What sleep stage is Theta waves observed?

A

Stage 1

150
Q

What sleep stages are slo w wave stages?

A

1-4

151
Q

What stages are delta waves observed?

A

Stage 3-4

152
Q

Which stages of sleep are categorised as deep sleep?

A

3-4

153
Q

What does EEG recording of REM sleep mirror?

A

Wakefulness (fast waves)

154
Q

What stage of sleep do dreams occur?

A

REM sleep

155
Q

How often does REM sleep cycle/last for?

A

Occurs every 90 mins and lasts 5-30 mins

156
Q

What is the name of a specific sleep disorder & what are the different types?

A

Insomnia

Primary & secondary

157
Q

In what stage of sleep do nightmares occur?

A

REM sleep

158
Q

In what stage of sleep do night terrors occur?

A

Deep Delta sleep

159
Q

What is somnambulism? When does it occur?

A

Sleep walking

Stage 4 sleep

160
Q

What sleep stage to patients with narcolepsy enter straight in to?

A

REM sleep

161
Q

Where is the “master clock” which regulates the circadian rhythm?

A

Suprachiasmatic nuclei in hypothalamus

162
Q

What is the function of the vestibular system?

A

Sensation of balance & posture

163
Q

Where is the vestibular system found?

A

Inner ear (temporal bone)

164
Q

What is the vestibular system composed of?

A

Membranous fluid filled canals (labyrinths)

165
Q

What is the vestibular apparatus composed of?

A

3 semi-circular canals (superior, posterior & horizontal)
Utricle
Saccule

166
Q

Where are sensory hair cells found in the vestibular apparatus?

A

Ampulla
Utricle
Saccule

167
Q

What is the name given to both the utricle & saccule combined?

A

Otolith organs

168
Q

What do the otolith organs detect?

A

Changes in linear acceleration

169
Q

What does the saccule specifically sense?

A

Vertical movement

170
Q

What does the utricle specifically sense?

A

Back/front movement

171
Q

What do the semi-circular canals sense?

A

Rotational acceleration

172
Q

Where are the sensory receptors in the SCCs found?

A

Swellings at the base of canals called Ampulla

173
Q

What is the name of the sensory receptors in the SCCs?

A

Cristae

174
Q

What is the name of the flexible gelatinous structure found in the ampulla?

A

Cupula

175
Q

What is the name of the fluid which moves through the SCCs?

A

Endolymph

176
Q

What is embedded within the gelantinous cupula?

A

Cilia of hair cells

177
Q

What way will endolymph move in side the SCCs?

A

Opposite direction to movement

178
Q

What accounts for dizziness?

A

Suddenly stopping following rotational acceleration will result in continued motion of endolymph = dizziness

179
Q

What are the 2 types of cilia called at the hair cells?

A

Kinocilium (1 large)

Stereocilia (multiple small)

180
Q

What will happen is cilia are distorted towards kinocilium?

A

Depolarisation

Increased APs

181
Q

What will happen is cilia are distorted away kinocilium?

A

Hyperpolarisation

Decreased Abs

182
Q

What are the sensory receptors of the otolith organs called?

A

Maculae

183
Q

The maculae in the utricle are orientated in what plane?

A

Horizontal

184
Q

The maculae in the saccule are orientated in what plane?

A

Vertical

185
Q

What is the gelatinous membrane called found at the maculae?

A

Otolith membrane

186
Q

What is embedded in the otolith membrane?

A

Otolith crystals

187
Q

What forces affect otoliths?

A

Gravitional

188
Q

Moving the head back/forward with result in what happening at maculae?

A

Gravitational movement of otolith & membrane, thus moving cilia and causes firing of APs

189
Q

If the head is tilted backwards, what will happen to no. of APs?

A

Cilia will move towards the kinocilium and cause depolarisation (inc. APs)

190
Q

If the head is tilted FORWARDS, what will happen to no. of APs?

A

Cilia will move away from kinocilium and cause hyperpolarisation (decreased Aps)

191
Q

Which nerve carries information from the 2 maculae & 3 cristae of SCCs?

A

Vestibular nerve

192
Q

Where does the vestibular nerve carry information to??

A

Cerebellum

193
Q

What is the name for the perception of movement & body position?

A

Kinaesthesia

194
Q

Name some of the vestibular system reflexes

A

Tonic labyrinthine reflex
Dynamic righting reflex
Vestibule-Ocular reflex

195
Q

What does the tonic labyrinthine reflex do?

A

Keeps the axis of the head in relationship with the rest of the body

196
Q

What does the dynamic righting reflex do?

A

It keeps you upright if you trip, rapid postural changes

197
Q

What are the different reflex tests of the vestibulo-ocular reflex?

A

Static

Dynamic Vestibular Nystagmus

198
Q

What is the static reflex testing?

A

Movement of the head results in involuntary eye movements in order to maintain upright image

199
Q

What is the dynamic vestibular nystagmus?

A

Saccidic movements of the eye which rotate against the direction of movement

200
Q

If there is R nystagmus, which direction will the rapid eye movement be observed?

A

Right sided eye flick

201
Q

What ways can nystagmus be tested?

A
Post-rotational nystagmus
Caloric stimulation (cold/hot water)
202
Q

If hot water is injected into outer ear, which way will nystagmus be observed?

A

Same side as ear injected

203
Q

What is the mnemonic used to remember the side to which nystagmus occurs with cold/hot water?

A

COWS

204
Q

What is kinetosis?

A

Motion sickness

205
Q

What is labyrinthitis?

A

Infection of the vestibular system

206
Q

What is Meniers disease caused by?

A

Increased endolymph resulting in increased pressure

207
Q

What symptoms are observed with Menieres disease?

A

Nausea
Tinnitus
Vertigo
Nystagmus