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Flashcards in Neuro Physiology Deck (207)
1

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

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

2

What do lateral spinal pathway control?

Voluntary movements of distal muscles

3

What do ventromedial spinal pathways control?

Control posture & locomotion

4

Where does the CS tract cross over?

Medulla

5

What does the right motor cortex control?

Left side (motor control)

6

Where do CST neurons synapse?

Ventral horn

7

Where does the Rubrospinal tract originate?

Red nucleus (midbrain)

8

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

Fine movements of hands & arms lost

9

If the CST alone is lesioned what will be observed?

Some deficits seen however function will reappear after a few months

10

What is the Brodmanns area associated with motor control?

Area 4

11

What are the 2 ventromedial pathways called?

Vestibulospinal
Tectospinal tracts
Reticulospinal tract

12

What is the vestibulospinal tract responsible for?

Stabilises head & neck

13

What is the tectospinal tract responsible for?

Ensures eyes remain stable as body moves

14

Where do the reticulospinal tracts originate?

Brainstem

15

What is the function of the reticulospinal tracts?

Maintains balance & body posture

16

What muscles does the reticulospinal tract activate?

Trunk muscles
Antigravity muscles

17

Where are LMNs found?

Ventral horn of spinal cord

18

Medial motorneurones will control which muscles?

Axial & proximal limb muscles

19

Lateral motor neurones will control which muscles?

Distal limb muscles

20

What is another name for he primary motor cortex?

Pre-central gyrus

21

What lies in front of the primary motor cortex?

Pre-motor cortex (PMA)

22

Stimulating the right primary motor cortex will result in what?

Twitching of right limb

23

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

Somatosensory
Proprioceptive
Visual

24

Axons from which 2 brain areas converge on Area 6?

Prefrontal cortex
Posterior Parietal cortex

25

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

Area 6 - pre-motor cortex

26

What is Area 6 responsible for?

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

27

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

PMA - Premotor cortex

28

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

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

29

What symptoms/signs will be observed with cortical damage?

Contralateral flaccidity
Hyperreflexia
Babinski reflex - extension
Spasticity
Clonus

30

Describe the loop of information from cortex to basal ganglia

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

31

What is the corpus striatum? Role?

Caudate nucleus & putamen

Input zones of basal ganglia

32

What is the corticstriatal pathway?

Inputs running from the cortex to the basal ganglia

33

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

Substantia niagra degeneration (dopaminergic neurons)

34

What are some of the classical signs of Parkinsons disease?

Slowness in voluntary movements
Increase muscle tone
Tremors in hands

35

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

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

36

What are some of the signs associated with Huntingtons disease?

Hyperkinesia - chorea
Dementia
Personality disorder

37

What is chorea?

Spontaneous, uncontrolled rapid flicks & movements

38

A lesion in the cerebellum will result in what?

Uncoordinated movements = Ataxia

39

Where do preganglionic sympathetic nerves synapse?

Sympathetic chain

40

What cranial nerves have parasympathetic innervation?

3,7,9,10

41

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

Ach
Nicotinic

42

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

Ach
Nicotinic

43

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

Ach
Muscarinic

44

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

Noradrenalin
Adrenergic

45

At the adrenal medulla, what stimulates release of adrenalin?

Sympathetic postganglionic fibres

46

In the eye, sympathetic activation causes what?

Contracts radial muscle = pupillary dilation

Relaxtion of ciliary body = focusses far away

47

B2 adrenergic receptors usually stimulate_____.

Relaxation

48

Alpha 1 adrenergic receptors usually stimulate ______.

Contraction

49

In parasympathetic activation, what happens to the eye?

Contraction of sphincter muscle = pupillary constriction
Ciliary body contraction = lens focusses close up

50

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

Alpha 1 agonist
Muscarinic antagonist

51

In blood vessels, sympathetic innervation can cause _____ or _____

Vasconstriction (A1) or vasodilation (B2)

52

Where in the body can the sympathetic system cause vasodilation?

Skeletal muscle
Cardiac muscle

53

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

Relaxation of smooth muscle

54

What will happen in the Valsalva manoeuvre?

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

55

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

Nociceptors
Chemoreceptors
Mechanoreceptors
Thermoreceptors
Proprioceptors

56

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

Receptor (generator) potential

57

The size of the ______ encodes the intensity of stimulus.

Generator potential - graded potential

58

The frequency of _____ encodes the intensity of stimulus.

Action potential

59

What does the receptive field encode?

The location of the stimulus

60

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

2 point discrimination tests

61

What are the 3 primary afferent cutaneous sensory fibres?

Ab
Ao
C

62

Which is the fastest sensory afferent?

Ab (large myelinated fibres)

63

Which is the slowest sensory afferent?

C (unmyelinated fibres)

64

What types of sensation do Ab fibres carry?

Touch
Pressure
Vibration

65

What types of sensation do Ao fibres carry?

Fast pain
Cold
Pressure

66

What types of sensation do C fibres carry?

Slow pain
Warmth

67

What sensory afferents carry information about proprioception?

Ab
Aa

68

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

Ipsilateral dorsal column (carrying mechanoreceptor/ proprioceptive info)

69

In which spinal column do C & Ao fibres ascend?

Contralateral spinothalamic tracts

70

How many neurones are present in ascending tract?

3

71

If damage occurs to dorsal column what will be observed?

Loss of pressure, touch, vibration of same side

72

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

Loss of pain sensation on opposite side

73

Convergence will result in _____ acuity

Reduced

74

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

Lateral inhibition

75

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

Adaption

76

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

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

77

What fibres would be responsible for fast stabbing pain?

Ao fibres

78

Which fibres would be responsible for slow dull pain?

C fibres

79

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

Bradykinin
Prostaglandin
Histamine

80

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

K channels - hyper polarise cell therefore inhibit signal transduction

81

Where do Ao/C fibres synapse?

Dorsal horn

82

What mediates Gate control theory?

Inhibitory interneuron
Descending inhibitory pathways

83

What 2 ways can the inhibitory interneuron be activated ?

By Ab fibres - rubbing it better (mechanoreceptors)

Descending pathways

84

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

Releases opiate peptides which inhibit synaptic release

85

What is another name for opiate peptides?

Endorphins

86

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

PAG
NRM

87

What does prostaglandin do at the sensory nerve terminal?

PGN sensitises nociceptors to bradykinin

88

How do NSAIDs mediate their action?

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

89

How do TENS machines work?

Stimulate Ab fibres therefore activating inhibitory interneuron, reducing synaptic transmission

90

How does morphine mediate pain relief?

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

91

How do local anaeasthetics block pain transmission?

Block Na APs therefore all axonal transmission

92

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

Thalamus

93

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

Somatosensory cortex
Cingulate gyrus
Limbic system

94

Where does pain perception occur?

Somatosensory cortex

95

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

Peri-aquaductal grey
Dorsal horn

96

What is hyperalgesia?

Exaggerated response to pain from normal stimuli

97

What is allodynia?

Decreased threshold for pain response

98

What are the 3 components of central sensitisation to pain?

Wind-up
Classical
Long term potentiation

99

How does wind-up central sensitisation mediate action?

Increases release of NT therefore increased response of neurons

100

How does CLASSICAL central sensitisation mediate action?

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

101

How does long term potentiation central sensitisation mediate action?

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

102

How long does acute pain last for?

1 month & resolves with healing of tissue damage

103

How long does chronic pain last?

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

104

Which type of pain is protective?

Acute

105

What type of pain is associated with acute pain?

Nociceptive pain

106

What type of pain is associated with poorly localised presentation?

Neuropathic

107

What is pain?

A sensory perception of the mind (not a stimulus)

108

What is cognition?

Highest brain function
Integration of all sensory information to make sense of situation

109

What are the 3 components of learning & memory?

Hippocampus
Thalamux
Cortex

110

What does the hippocampus do in memory?

Formation of memory

111

What part does the cortex have in memory formation?

Stores memory

112

What part does the thalamus play in memory formation?

Searches & accesses memory

113

What areas compose the limbic system?

Hypothalamus
Hippocampus
Cingulate gyrus
Amygdala

114

What areas in the limbic system are central to learning?

Punishment
Reward areas

115

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

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

116

What are the different types of memory?

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

117

Which type of memory is described as working memory?

Short term memory

118

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

Short term memory

119

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

Consolidated and stored in long term memory

120

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

Amnesia

121

What are the 2 forms of amnesia?

Anterograde
Retrograde

122

What will anterograde amnesia result in?

Inability to form new memories

123

What will retrograde amnesia result in?

Inability to retrieve old memories

124

What is intermediate long term memory dependant on?

Chemical changes at the presynaptic neuron

125

What is long term memory (LTM) dependant on?

Structural changes at the synapse

126

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

Increase in NT release sites

Increase in vesicle & NT stored on pre-synpatic side

Increase in number of presynaptic terminals

127

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

Long term potentiation

128

What are the 2 types of LTM?

Declarative
Procedural

129

What is declarative LTM?

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

130

What is procedural LTM?

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

131

How can short term memories be converted to LTM?

Consolidation (strengthening of synaptic connections by repetition)

132

What composes the Papez circuit?

Hippocampus
Mammillary bodies
Anterior thalamus
Cingulate gyrus

133

What is the definition of sleep?

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

134

What chemical is the precursor for melatonin?

Serotonin

135

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

Inability to sleep

136

Where is melatonin produced?

Pineal glands

137

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

Suprachiasmatic nuclei (SCN)

138

What does activity of the SCN in the hypothalamus stimulate?

Release of melatonin

139

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

Orexin

140

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

Narcolepsy (inability to stay awake)

141

Where is the main sleep centre of the brain?

Reticular formation

142

What does EEG stand for?

ElectroEncepheloGram -assess neuronal activity

143

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

Alpha
Beta
Theta
Delta

144

What EEG waves are associated with awake, relaxed?

alpha waves (^ are, ^ amplitude)

145

What EEG waves are associated with being awake & alert?

Beta waves (^ freq, low amplitude)

146

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

Theta waves (Low freq)

147

What EEG waves are associated with deep sleep?

Delta waves (low freq, high amplitude)

148

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

5

149

What sleep stage is Theta waves observed?

Stage 1

150

What sleep stages are slo w wave stages?

1-4

151

What stages are delta waves observed?

Stage 3-4

152

Which stages of sleep are categorised as deep sleep?

3-4

153

What does EEG recording of REM sleep mirror?

Wakefulness (fast waves)

154

What stage of sleep do dreams occur?

REM sleep

155

How often does REM sleep cycle/last for?

Occurs every 90 mins and lasts 5-30 mins

156

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

Insomnia

Primary & secondary

157

In what stage of sleep do nightmares occur?

REM sleep

158

In what stage of sleep do night terrors occur?

Deep Delta sleep

159

What is somnambulism? When does it occur?

Sleep walking
Stage 4 sleep

160

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

REM sleep

161

Where is the "master clock" which regulates the circadian rhythm?

Suprachiasmatic nuclei in hypothalamus

162

What is the function of the vestibular system?

Sensation of balance & posture

163

Where is the vestibular system found?

Inner ear (temporal bone)

164

What is the vestibular system composed of?

Membranous fluid filled canals (labyrinths)

165

What is the vestibular apparatus composed of?

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

166

Where are sensory hair cells found in the vestibular apparatus?

Ampulla
Utricle
Saccule

167

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

Otolith organs

168

What do the otolith organs detect?

Changes in linear acceleration

169

What does the saccule specifically sense?

Vertical movement

170

What does the utricle specifically sense?

Back/front movement

171

What do the semi-circular canals sense?

Rotational acceleration

172

Where are the sensory receptors in the SCCs found?

Swellings at the base of canals called Ampulla

173

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

Cristae

174

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

Cupula

175

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

Endolymph

176

What is embedded within the gelantinous cupula?

Cilia of hair cells

177

What way will endolymph move in side the SCCs?

Opposite direction to movement

178

What accounts for dizziness?

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

179

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

Kinocilium (1 large)
Stereocilia (multiple small)

180

What will happen is cilia are distorted towards kinocilium?

Depolarisation
Increased APs

181

What will happen is cilia are distorted away kinocilium?

Hyperpolarisation
Decreased Abs

182

What are the sensory receptors of the otolith organs called?

Maculae

183

The maculae in the utricle are orientated in what plane?

Horizontal

184

The maculae in the saccule are orientated in what plane?

Vertical

185

What is the gelatinous membrane called found at the maculae?

Otolith membrane

186

What is embedded in the otolith membrane?

Otolith crystals

187

What forces affect otoliths?

Gravitional

188

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

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

189

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

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

190

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

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

191

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

Vestibular nerve

192

Where does the vestibular nerve carry information to??

Cerebellum

193

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

Kinaesthesia

194

Name some of the vestibular system reflexes

Tonic labyrinthine reflex
Dynamic righting reflex
Vestibule-Ocular reflex

195

What does the tonic labyrinthine reflex do?

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

196

What does the dynamic righting reflex do?

It keeps you upright if you trip, rapid postural changes

197

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

Static
Dynamic Vestibular Nystagmus

198

What is the static reflex testing?

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

199

What is the dynamic vestibular nystagmus?

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

200

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

Right sided eye flick

201

What ways can nystagmus be tested?

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

202

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

Same side as ear injected

203

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

COWS

204

What is kinetosis?

Motion sickness

205

What is labyrinthitis?

Infection of the vestibular system

206

What is Meniers disease caused by?

Increased endolymph resulting in increased pressure

207

What symptoms are observed with Menieres disease?

Nausea
Tinnitus
Vertigo
Nystagmus