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Phase 1 mine > Neuro > Flashcards

Neuro Flashcards

1
Q

what part of the brain encompasses the rhombencephalon

A

hindbrain = medulla oblongata/pons/cerebellum

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2
Q

what is white matter

A

a collection of nerve fibres with few/no neural cell bodies = forms deeper parts of brain = myelinated

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3
Q

what is grey matter

A

aggregations of neuronal cell bodies and local processes = forms surface of cerebral hemispheres = non-myelinated

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4
Q

what is the neuropil

A

space between neuronal cell bodies in grey matter

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5
Q

which parietal lobe is normally dominant

A

left

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6
Q

where is the primary sensory area located

A

post central gyrus

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7
Q

what is the parietal lobe responsible for (4)

A

perception
interpretation of sensory info
complex, meaningful motor response
language

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8
Q

what is the non dominant parietal lobe responsible for

A

visuospatial functions

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9
Q

what is the frontal lobe responsible for (5)

A 
higher intellect
mood
personality
social conduct
language
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10
Q

what is the temporal lobe responsible for (4)

A

short term memory
equilibrium
emotion
primary auditory cortex

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11
Q

what is wernicke’s area responsible for

A

understanding spoken word

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12
Q

what is the occipital lobe responsible for

A

vision = contains primary visual/visual association cortex

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13
Q

what is the limbic system involved in (4)

A

emotion
memory
behavior
olfaction (smell)

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14
Q

name 2 systems that the limbic system influences

A

endocrine system

autonomic NS

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15
Q

name the 3 layers of the cranial meninges

A

dura mater
arachnoid mater
pia mater

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16
Q

what are the 2 layers of the dura mater

A

inner meningeal layer

outer endosteal layer

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17
Q

what are the falx cerebri

A

the dura mater between 2 cerebral hemispheres

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18
Q

what are the falx cerebelli

A

the dura mater between the cerebellar lobes

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19
Q

what are the sinuses

A

non-fused spaces between 2 layers of dura mater

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20
Q

what does the subarachnoid space contain

A

CSF

blood vessels

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21
Q

what are the zonula occludentes

A

tight junctions linking cells of the arachnoid mater together

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22
Q

what binds the pia mater to the brain

A

astrocytes

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23
Q

where is the motor cortex located

A

posterior precentral gyrus

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24
Q

where is the foramen of Lushka

A

lateral sides of 4th ventricle = pontine cisterna

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25
Q

where is the foramen of Magendie

A

medial side of 4th ventricle = cerebellomedullary cisterna

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26
Q

where do external cerebral veins drain

A

into sagittal sinus and down into jugular vein

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27
Q

what structures does the cavernous sinus contain

A 
O TOM CAT
oculomotor nerve
trigeminal - opthalmic, maxillary
internal Carotid artery
abducens nerve
trochlea nerve
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28
Q

what is CSF formed by

A

choroid plexus by ependymal cells

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29
Q

where is CSF reabsorbed

A

arachnoid villi mainly along sagittal sinus

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30
Q

what are arachnoid granulations

A

arachnoid villi become calcified and form granules

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31
Q

what is the role of CSF

A
  1. cushioning/protection
  2. removes toxins
  3. creates CSF/blood barrier at choroid plexus to prevent contact of external things with ventricles
  4. buoyancy = suspends brain
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32
Q

where does the CSF lie in the brain

A

between pia and arachnoid mater

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33
Q

what is Broca’s area responsible for

A

language production

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34
Q

what is the corpus callosum

A

large bundle of white matter connecting 2 cerebral hemispheres

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35
Q

what is the fornix

A

white matter connecting hippocampus with diencephalon and precommisural septum

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36
Q

what 3 things make up the midbrain

A

tegmentum
tectum
cerebral peduncles

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37
Q

what are the superior colliculi associated with

A

visal system

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38
Q

what are the inferior colliculi associated with

A

auditory system

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39
Q

where are the colliculi located

A

directly inferior to the pineal gland

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40
Q

what structure separates the colliculi of the midbrain

A

cruciform sulcus

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41
Q

what structure separates the cerebral peduncles

A

interpeduncular fossa

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42
Q

what do the superior cerebellar peduncles do

A

connect cerebellum to midbrain

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43
Q

what do middle cerebellar peduncles do

A

connect cerebellum to pons

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44
Q

what to inferior cerebellar peduncles do

A

connect cerebellum to medulla

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45
Q

what 3 layers make up the blood-brain barrier

A
  1. endothelial cells
  2. pericytes
  3. astrocytes
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46
Q

name 5 features of the blood brain barrier

A
  1. endothelial tight junctions
  2. astrocyte end feet
  3. pericytes
  4. continuous basement membrane lacking fenestrations
  5. requires specific transporters for glucose
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47
Q

what does the vertebral artery supply

A

= 20%
posterior cerebrum
contents of posterior cranial fossa

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48
Q

what does the internal carotid artery

A

=80%
anterior cerebrum
middle cerebrum
diencephalon

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49
Q

what is the blood supply of the frontal lobe

A

anterior cerebral artery

middle cerebral artery

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50
Q

what level does the common carotid artery bifurcate

A

c4

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51
Q

what is the blood supply of the parietal lobe

A

anterior cerebral artery

middle cerebral artery

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52
Q

what is the blood supply of the temporal lobe

A

middle cerebral artery

posterior cerebral artery inferior portion

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53
Q

what is the blood supply of the occipital lobe

A

posterior cerebral artery

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54
Q

what is a berry aneurysm

A

congenital sac-like out pouching of an inter-cranial artery progressively enlarging until rupture

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55
Q

what does a rupture of a berry aneurism cause

A

subarachnoid or intracerebral haemorrhage

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56
Q

where does a berry aneurysm most commonly occur

A

around circle of willis commonly anterior communicating artery

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57
Q

what is a stroke

A

ischaemic or haemorrhagic leading to intracerebral/subarachnoid haemorrhage = 3rd most common cause of death worldwide

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58
Q

where does the superior brachium nerve pathway do

A

conveys visual information from lateral geniculate body to superior colliculi

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59
Q

what does the inferior brachium nerve pathway do

A

conveys auditory information from medial geniculate body to inferior colliculi

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60
Q

which 2 cranial nerves originate from the cerebrum

A

olfactory and optic

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61
Q

how do you test the occulomotor III, trochlear IV and abducens nerve VI

A

tested together = external occular muscles
make patient follow your finger and make H shape
each eye separately then both together

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62
Q

how do you test the trigeminal nerve V

A 
sensory = all sensory modalities of 3 main branches
motor = ask patient to clench teeth = temporal and masseter muscles
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63
Q

how do you test the facial nerve VII

A 
shut eyes as tight as possible 
raise eyebrows
smile
whistle
taste sensation anterior 3rd tongue
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64
Q

how do you test the vestibulocochlear nerve VIII

A

whisper in each ear then ask patient to repeat

tuning fork

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65
Q

how do you test for the glossopharyngeal nerve IX and vagus nerve X

A

tickle back of pharynx = IX sensory

note if reflex contraction occurs = X motor branch

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66
Q

how do you test the accessory nerve XI

A

test function of trapezius by asking patient to shrug shoulders against resistance
test sternocleidomastoid by asking patient to turn head on each side against resistance

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67
Q

how do you test the hypoglossal nerve XII

A

ask patient to push tongue out as far as possible = straight or one side

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68
Q

which spinal vertebrae have foramen transversium

A

cervical

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69
Q

what is the upper most palpable spinous process

A

c7

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70
Q

at what level is the highest point of the iliac crest

A

in line with L3-L4

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71
Q

what movements do cervical vertebrae provide

A

flexion
extension
lateral flexion
rotation

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72
Q

what movements do thoracic vertebrae provide

A

small amount forward flexion
lateral flexion
rotation = MOST ROTATION OF ALL

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73
Q

what movements do lumbar vertebrae provide

A

flexion
extension
lateral bending
rotation

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74
Q

what is the nucleus pulposus made of

A

well hydrated gel protoglycan/collagen

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75
Q

what is the annulus fibrosus made of

A

10-12 concentric layers of collagen

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76
Q

where is the epidural space

A

space between vertabrae and dura mater of spinal cord

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77
Q

how many vertebrae does each spinal section have

A 
cervical = 7
thoracic = 12
lumbar = 5
sacrum = 5 fused
coccyx = 4 fused
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78
Q

what fibres do the dorsal roots carry

A

sensory = afferent

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79
Q

what fibres do the ventral roots carry

A

motor = efferent

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80
Q

where does the spinal cord end

A

between L1 and L2

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81
Q

what is the conus medullaris

A

tapering end of spinal cord

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82
Q

what is the filum terminale

A

fibrous strand extending from conus medullaris to coccyx

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83
Q

what is the cauda equina

A

formed from lumbar and sacral nerve roots hanging obliquely down from below conus medullaris

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84
Q

describe the interaction between c1 and c2

A

c1 = atlas
c2 = axis
odontoid peg of c2 becomes vertebral body for c1

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85
Q

name the conscious tracts

A

dorsal column-medial lemniscal pathway

anterolateral system

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86
Q

name the unconscious tracts

A

spinocerebellar tracts

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87
Q

where do the spinal nerves leave the cervical vertebrae

A

1 vertebra higher than corresponding vertebra except c8 below by 1 vertebra

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88
Q

where do spinal nerves leave the thoracic, lumbar, sacral vertebrae

A

below the corresponding vertebrae

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89
Q

name the dorsal/medial lemniscal columns in the brainstem and in the spinal cord

A

cuneate and gracile nucleus in brainstem

cuneate and gracile fasciculus in spinal cord

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90
Q

the cuneate fasiculus carries information from where

A

upper body ascending in lateral tract

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91
Q

the gracile fasciculus carries information from where

A

lower body ascending in medial tract

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92
Q

describe the path of the dorsal column medial lemniscal pathway

A
  1. first order from limbs to medulla through dorsal column
  2. second order in gracile/cuneate nucleus in medulla decussate then travel in medial lemniscus to contralateral thalamus
  3. third order from thalamus to internal capsule to sensory cortex
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93
Q

what information does the dorsal/medial lemniscal columns carry

A

fine touch
vibration
proprioception

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94
Q

name the corticospinal tracts and what direction are they

A

descending

lateral/anterior

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95
Q

describe the pathway of corticospinal tract

A

originate from motor/premotor cortex
descend through internal capsule
pass through crus cerebri to pons to medulla

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96
Q

describe the lateral corticospinal tract

A

decussate in the medullary pyramids - contralateral innervation 85%
descend to spinal cord
terminate in ventral horn for LMN
motor innervation for limbs/digits

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97
Q

describe the anterior corticospinal tract

A

remains ipsilateral - 15%
decussate at spinal cord level of innervation
terminate in ventral horn for LMN
motor innervation of trunk

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98
Q

what information do corticospinal tracts carry

A

motor control of voluntary muscles
lateral = limbs
anterior = axial

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99
Q

name the spinothalamic tracts, which direction they travel and what information they carry

A

ascending
anterior = crude touch/pressure
lateral = pain/temperature

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100
Q

describe the path of the spinothalamic tract

A
  1. first order neurons from peripheral nerves to synapse in substantia gelatinosia
  2. second order decussate in spinal cord then travel up via lateral/anterior spinothalamic tract to thalamus
  3. third order neurons from thalamus to internal capsule to sensory cortex
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101
Q

what are the pyramidal tracts responsible for

A 
corticospinal = musculature of body
corticobulbar = musculature of head/neck
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102
Q

name the extra-pyramidal tracts

A 
= all descending
tectospinal
rubrospinal = non decussating
vestibulospinal
reticulospinal
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103
Q

name the 3 neurones in the dorsal column medial lemniscus pathway

A
  1. dorsal root ganglion
  2. cuneate and gracile nuclei
  3. ventral posterolateral nucleus of thalamus
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104
Q

where does the spinothalamic tract decussate

A

anterior white commisure

105
Q

where do the lateral and medial spinothalamic tracts merge

A

medulla = forms spinal lemniscus

106
Q

what is brown sequard syndrome

A

rare condition where lesion on spinal cord results in weakness on one side of body and loss of sensation of other

107
Q

what is the tectospinal tract responsible for

A

contralateral

head movement to visual stimuli

108
Q

what is the rubrospinal tract responsible for

A

contralateral from red nucleus

fine hand motor

109
Q

what is the vestibulospinal tract responsible for

A

from vestibular nuclei

ipsilateral balance and posture

110
Q

what is the reticulospinal tract responsible for

A

ipsilateral voluntary movement

111
Q

which side will experience weakness in brown sequard syndrome

A

ipsilateral weakness below lesion due to damage to descending motor tract

112
Q

which side will experience less of sensation in brown sequard syndrome

A

ipsilateral loss of dorsal column proprioception below lesion as ascending tract damaged before can reach medulla
contralateral loss of pain/temp below as spinothalamic decussate at vertebral level

113
Q

what are the overall consequences of brown sequard syndrome

A

ipsilateral loss of proprioception, motor, fine touch

contralateral loss of pain, temp, crude touch

114
Q

what is neurulation

A

process of formation of embryonic nervous system

115
Q

which cranial nerves are parasympathetic

A 
3 occulomotor
7 facial
9 glossopharyngeal
10 vagus
1973
116
Q

when does neurulation begin

A

3rd week

117
Q

describe the process of neurulation in the 3rd week

A
  1. ectoderm thickens in midline = becomes neural plate

2. neural plate bends dorsally and borders meet = become neural crest

118
Q

describe the process of neurulation in the 4th week

A
  1. neural tube closes = disconnect neural crest from ectoderm
  2. layer of neural crest cells
  3. notochord degenerates and mesoderm differentiate into somites
119
Q

what develops from neural crest cells

A 
forms most of peripheral NS
sensory dorsal rot ganglia of spinal chord
cranial nerves 5, 7, 9, 10
schwann cells
meninges 
dermis
120
Q

what does the neural tube develop into

A

brain and spinal chord

121
Q

what 3 primary brain vesicles have formed by week 5 and what do they represent

A 
prosencephalon = forebrain
mesencephalon = midbrain
rhombencephalon = hindbrain
122
Q

what does the mesencephalon further develop into to

A

corpora quadrigemina
tegmentum = colliculi
cerebral peduncles
aquaduct

123
Q

what does the rhombencephalon differentiate into and what does it further develop into

A
  1. metencephalon = pons, cerebellum

2. myelencephalon = medulla oblongata

124
Q

what is the 4th ventricle derived from

A

upper part = metencephalon

lower part = myelencephalon

125
Q

what causes anencephalus

A

failure of neural tube closure in brain

126
Q

what week does eye formation occur

A

3 weeks

127
Q

what occurs embryologically at 3, 5, 7, 9 months

A 
3 = basic structures
5 = myelination begun
7 = lobes cerebrum formed
9 = gyri/sulci formed
128
Q

when do CNS disorders generally occur

A

2nd trimester

129
Q

when is noxious (painful) stimuli first felt

A

19+ weeks as c-fibre connections are made

130
Q

where is working memory stored

A

prefrontal cortex

131
Q

what is involved in laying down new memories

A

mamillary bodies

132
Q

what are the 2 types of long term memory

A
  1. explicit = conscious e.g. remembering appointments

2. implicit = unconscious e.g. motor skills

133
Q

describe the 3 types of implicit memory and what area of the brain is responsible for it

A
  1. skills/habits = cerebellum/basal ganglia
  2. conditioned reflexes = cerebellum et al
  3. emotional = amygdala
134
Q

what is the amygdala responsible for

A

produces instinctive emotional output

responsible for emotional memory and fear

135
Q

how is the resting potential maintained

A 
membrane is semi-permeable 
Cl-/K+ move easily
Na+ low permeability 
Na+/K+ATPase pump = 3Na+ out 2K+ in 
K+ diffuses out via channels
= negative internal
136
Q

describe repolarisation and hyperpolarisation

A
  1. potential reaches around +30mv then Na+ voltage gated channels shut
  2. K+ channels open = K+ out of neuron = repolarisation
  3. K+ channels close slowly so continued outflow causes hyperpolarisation
  4. K+ channels all close = resting potential restored
137
Q

what is saltatory conduction

A

action potential jumps from node of ranvier to node as propagation occurs along axon

138
Q

name the 2 types of synaptic transmission

A

electrical

chemical = majority

139
Q

what is the effect of a higher concentration of neurotransmitter

A

= more likely binding will occur = action potential propogation

140
Q

how does myelin improve conduction

A

increase insulation = faster

nodes of ranvier = saltatory = faster

141
Q

what is multiple sclerosis

A

chronic autoimmune disorder = results in demyelination, gliosis, neuronal damage

142
Q

what are excitatory neurotransmitters

A

depolarise cell membrane increasing probability of action potential = causing an excitatory post synaptic potential EPSP = many Na+ leave and few K+ enter

143
Q

what are inhibitory neurotransmitters

A

hyperpolarise cell membrane = decrease probability of action potential = causing an inhibitory post synaptic potential IPSP = many K+ leave or many Cl- enter

144
Q

name the 3 types of synapses and give examples for each

A 
excitatory = glutamate
inhibitory = GABA
modulatory = associated with longer term changes in synaptic membrane = dopamine
145
Q

what is spatial summation

A

2 inputs occur at different locations in postsynaptic neuron

146
Q

what are the 5 processes of synaptic transmission

A
  1. manufacture
  2. storage = vesicles
  3. release = action potential
  4. interact with post-synaptic receptors
  5. inactivation = breakdown/reuptake
147
Q

what is the definition of pain

A

unpleasant sensory and emotional experience associated with actual potential tissue damage or described in terms of such damage

148
Q

what is acute pain

A

short term pain of less than 12 weeks

149
Q

what is chronic pain

A

continuous long term pain more than 12 weeks or persistent pain after trauma = cancerous or non-cancerous

150
Q

what is nociceptive pain

A

pain arising from actual/threatened damage to non-neuronal tissue
= due to activation . of nociceptors

151
Q

what is neuropathic pain

A

pain initiated/caused by primary lesion/dysfunction of nervous system

152
Q

what is analgesia

A

selective suppression of pain without effects on consciousness/other sensations

153
Q

what is anaesthesia

A

uniform suppression of pain = no pain felt at all sometimes loss of consciousness

154
Q

what is the melzack-wall pain gate

A

states that non-painful input closes the ‘gate’ to painful input = preventing pain sensation from travelling to somatosensory cortex to be perceived/felt

155
Q

what are nociceptors

A

sensory neurons in any area of body that sense pain:
externally = skin/cornea/mucosa
internally = viscera/joints/muscles

156
Q

where are the cell bodies of nociceptors found

A

body = dorsal root ganglion

head and neck = trigeminal ganglion

157
Q

what does it mean that most nociceptors are ‘poly-modal’

A

can detect thermal/chemical/mechanical pain

158
Q

name the afferent pain fibres

A

alpha delta fibres

c fibres

159
Q

describe alpha delta fibres characteristics

A

small diameter
thinly myelinated
carry touch/pressure/temperature/FAST PAIN
medium conduction speed

160
Q

describe c fibres characteristics

A

smallest diameter
unmyelinated
carries slow pain/temperature/touch/pressure/itch
slowest conduction speed

161
Q

what do c fibres respond to

A

thermal/mechanical/chemical stimuli

162
Q

what do a delta fibres respond to

A

mechanical stimuli over certain intensity

163
Q

what is the pain quality produced by c fibres

A

dull
aching
slow
burning

164
Q

what pain quality is produced by a delta fibres

A

well localised
sharp
stinging
fast

165
Q

describe the mechanism of pain

A
  1. noxious stimuli = damaged cells release substance P
  2. nociceptors activated on alpha delta/c fibres = lower threshold
  3. action potential generated in pain fibres = synapse in substantia gelitanosa
  4. 2nd order neurones to lateral spinothalamic tract to thalamus
166
Q

what neurotransmitters do a delta fibres release

A

glutamate

167
Q

what neurotransmitters do c fibres release

A

glutamate and substance p

168
Q

what is substance p

A

slow acting = involved in mediation of dull/aching pain

169
Q

what is the role of prostaglandin

A

do not cause pain

lower threshold of C fibre nociceptors = lower conc of bradykinin/histamine required to activate nociceptor

170
Q

what is the role of the thalamus in pain

A

all sensation except olfaction pass through

contains multiple nuclei for relay/association function

171
Q

what is the role of the insula in pain

A

where degree of pain is judged = subjective aspect of pain perception

172
Q

what is the role of the cingulate gyrus in pain

A

linked with limbic system = emotional response to pain

173
Q

where is periaquaductal grey found

A

grey matter located around cerebral aquaduct

174
Q

how does periaquaductal grey lead to reduced pain sensation

A

contains high concentration of opioid receptors/endogenous opioids
when activated =
inhibits nociceptive impulses reaching thalamus
inhibits presynaptic calcium movement
potassium release = hyperpolarise

175
Q

describe the descending pain pathway

A

somatosensory cortex to periaquaductal grey in midbrain

same as spinothalamic but descending

176
Q

how do opioids work

A

mimic effect of endogenous opioids = bind to opioid receptors in periaquaductal grey = profound analgesia

177
Q

what role does the anterior cingulate gyrus have in registering pain

A

registers physical pain

emotional reaction to pain

178
Q

what is acetylcholinesterase

A

enzyme found on pre/postsynaptic membrane

destroys ACh = release choline and acetate

179
Q

what is the motor end plate

A

connection between muscle fibre and synapse

180
Q

where is ACh found in the neuromuscular junction

A

in vesicles in the axon terminals of the motor neuron

181
Q

what is a neuromuscular junction

A

junction of axon terminal and motor end plate

182
Q

describe neuromuscular transmission 3 steps

A
  1. ACh released from presynaptic terminal = diffuse towards muscle
  2. ACh binds to cholinergic nicotinic receptors on sarcolemma
  3. depolarisation of sarcolemma = Ca2+ released from sarcoplasmic reticulum (for muscle contraction)
183
Q

why is an EPP larger than an EPSP

A

neurotransmitter released over larger surface area = more binding to receptors

184
Q

what is a motor unit

A

an alpha motor neuron and all the extrafusal skeletal muscle fibres it innervates

185
Q

what happens when an alpha motor neuron is depolarised

A

causes contraction in all of the muscle fibres in that unit then spreads throughout muscle = more contraction

186
Q

what type of synapse are neuromuscular junctions

A

all excitatory releasing ACh

187
Q

the less fibres a single motor unit innervates =

A

greater degree of movement e.g. fingertips/tongue

188
Q

what is the sarcolemma

A

cell membrane of muscle fibre

189
Q

what is a muscle spindle

A

intrafusal fibres innervated by gamma motor neurons

detect muscle stretch regardless of current length

190
Q

what is the role of stretch receptors

A

monitor muscle length and change of muscle length

191
Q

what are intrafusal fibres

A

modified muscle fibres within the muscle spindle

192
Q

what are intrafusal fibres innervated by

A

gamma motor neurons prevent spindle going slack during muscle contraction
= keep intrafusal fibres at set length to optimise muscle stretch detection

193
Q

what are the 2 types of stretch receptor and what is their role

A
  1. nuclear chain fibres = respond to how much muscle is stretched
  2. nuclear bag fibres = respond to magnitude and speed of stretch
194
Q

what are type 1a afferent sensory nerves

A

fast nerves innervating middle third of muscle spindle

195
Q

what are type 2 afferent sensory nerves

A

slower conducting nerves innervating superior and inferior thirds of muscle spindle

196
Q

what occurs in the muscle spindle when extrafusal fibres contract

A

muscle shortens = spindles go slack = cannot send signals via afferent sensory nerves
gamma motor neurons with alpha MN prevent spindle going slack

197
Q

what does muscle tension depend on

A

muscle length
load on muscles
degree of muscles fatigue

198
Q

what is the golgi tendon organ

A

collagen fibres in tendon innervated by afferent fibres

detect tension

199
Q

what are the sensory fibres of the golgi tendon organ

A

1b afferent fibres = run to anterior horn of spinal cord = slower than muscle spindle fibres

200
Q

how are golgi tendon organs activated

A

when muscle is stretched = extrafusal muscle fibres contract = tension exerted on tendon = collagen bundles are straightened = distorts GTO receptor endings

201
Q

how does the GTO regulate muscle tension

A

muscle generates too much force = activate GTO

1b afferent sensory neuron = inhibits/reduces activity of alpha motor neurons = decrease muscle contraction/force

202
Q

describe the knee jerk reflex

A
  1. strike patella = tendon pushed down = quadricep stretched
  2. muscle spindle detects stretch in muscle = activate afferent fibres
  3. afferent fibres stimulate alpha motor neurons
  4. alpha motor neurons innervate extrafusal fibres = quadricep contract
203
Q

describe a withdrawal reflex (step on pin)

A
  1. pain on skin = nociceptors activated
  2. sensory neuron synapse with interneuron then motor neuron
  3. motor neuron carry impulse to extrafusal fibres of muscles = activates flexor and inhibit extensor of muscle on ipsilateral leg = body moves away from painful stimuli
204
Q

what is an example of inverse stretch reflex

A

action of golgi tendon organ

205
Q

what causes the clasp knife reflex

A

1b afferent fibres from GTO inhibit alpha MN when GTO detects tension = inverse stretch reflex

206
Q

what is a clasp knife reflex

A

period of give after a time of resistance e.g. when a limb is flexed there is resistance and then resistance falls dramatically

207
Q

what area is responsible for voluntary movement

A

pyramidal tracts in the motor cortex = pre-central gyrus

208
Q

what pathways are responsible for voluntary movement

A

corticospinal tract

corticobulbar tract

209
Q

what part of voluntary movement involves the pre-motor cortex

A

planning of movement

incorporation of sensory info to movement

210
Q

what part of voluntary movement involves the primary motor cortex

A

execution of movement

211
Q

what pathways are involved in involuntary movement

A

tectospinal
vestibulospinal
reticulospinal
rubrospinal

212
Q

what are the upper motor neurons

A

descending pathways and neurons of motor cortex

213
Q

what problems are associated with a upper motor neuron lesion

A

weakness
altered muscle tone
fast twitching

214
Q

what are lower motor neurons

A

motor neurons of spinal cord and brainstem e.g. alpha/gamma

215
Q

what problems are associated with a lower motor neuron lesion

A

paralysis

decreased muscle tone

216
Q

name the 3 layers of the eye

A

fibrous outer
vascular
inner

217
Q

what makes up the fibrous layer of the eye

A

cornea

sclera

218
Q

what makes up the vascular layer of the eye

A

choroid
ciliary body
iris
lens

219
Q

what makes up the inner layer of the eye

A

retina = neural layer/pigmented layer

vitreous humour

220
Q

where is the primary visual cortex located

A

medial surface of hemisphere in region above and below calcarine sulcus = occipital lobe

221
Q

name the 3 layers of the retina and what they do

A
  1. photoreceptors = rods and cones for vision
  2. bipolar neurons = transmit impulse
  3. retinal ganglion cells = axons converge to form optic nerve
222
Q

what occular muscles does the occulomotor nerve superior branch supply

A

superior rectus

inferior rectus

223
Q

what occular muscles does the occulomotor nerve inferior branch supply

A

medial rectus

inferior obique

224
Q

what occular muscle does the abducens nerve supply

A

lateral rectus

225
Q

what occular muscle does the trochlear nerve supply

A

superior oblique

226
Q

what is the optic path of temporal axons

A

remain ipsilateral

227
Q

what is the optic path of nasal axons

A

cross at optic chiasm

228
Q

where do the axons of the visual pathway synapse

A

lateral geniculate body of thalamus

some = superior colliculus of midbrain

229
Q

what is the path of superior hemiretinae fibres from the lateral geniculate nucleus

A

pass superiorly through parietal lobe as baum’s loop

230
Q

what is the path of inferior hemiretinae fibres from the lateral geniculate nucleus

A

pass inferiorly through temporal lobe as meyer’s loop

231
Q

where do axons of visual pathway terminate

A

primary visual cortex = calcarine fissure

232
Q

what is the role of the outer ear

A

collect sound

233
Q

what is the role of the middle ear

A

transmission of sound

234
Q

what is the role of the inner ear

A

conversion of sounds to neural impulses

235
Q

describe the path of sound in the outer ear

A

pinna = directs sound
sound enters via external auditory canal
waves vibrate tympanic membrane
slow waves = low frequency and vice versa

236
Q

what nerve supplies the middle ear sensation

A

glossopharyngeal nerve

237
Q

name the 3 bones of the middle ear = ossicles and what is their role

A

malleus
incus
stapes
= transmit sound from tympanic membrane to oval window in inner ear

238
Q

name the 2 skeletal muscles of the middle ear and what is their role

A

tensor tympani = attached to malleus
stapedius = attached to stapes
= decrease movement of ossicles by contraction = protection

239
Q

what is the role of the eustacian tube

A

connects middle ear to pharynx

controls pressure = opens to equalise pressure at high altitudes/aeroplanes

240
Q

how do the skeletal muscles protect the ear

A

muscles act reflexively to continuous loud noise but cannot protect from sudden intermittent loud sounds

241
Q

what makes up the inner ear

A

cochlear

semi-circular canals

242
Q

describe the cochlear

A

spiral fluid filled space
divided by cochlear duct which is surrounded by fluid
scala vestibuli from oval window = runs above duct
scala tympani from round window runs below duct

243
Q

describe the fluid in the cochlear

A

cochlear duct filled with endolymph = high K+ low Na+
surrounded by perilymph = high Na+ low K+
Na+/K+ATPase powers auditory system

244
Q

where do the scala vestibuli and scala tympani connect

A

helicotrema

245
Q

describe the pathway of sound in the inner ear

A

sound waves = move tympanic membrane = transmit to ossicles = transmit to oval window = oval window moves in/out of scala vestibuli = creates waves of pressure across cochlear duct/some to helicotrema to be relieved by round window

246
Q

where is the organ of corti located

A

on basilar membrane = side of cochlear duct closest to scala tympani

247
Q

how are high and low pitch tones interpreted by the inner ear

A

nearest to middle ear = basilar membrane narrow and stiff = low frequency
closer to helicotrema = wider less stiff = high pitch

248
Q

describe the organ of corti

A

has receptor cells = mechanoreceptors with hairlike stereocilia

249
Q

describe the hair cells of the organ of corti

A

single row of inner hair cells = protrude into endolymph to convert movement into receptor potentials
3-5 rows outer hair cells = embedded in tectorial membrane = fine tuning

250
Q

describe auditory conduction

A
  1. pressure waves displace basement membrane = stereocilia bens
  2. K+ channels open = K+ in from endolymph = depolarisation
  3. Ca2+ channels open on basement membrane = Glutamate released
  4. stimulates cochlear branch of vestibulocochlear nerve VIII
  5. to superior ollivary body to medial geniculate nucleus in thalamus to auditory cortex
251
Q

what is bell’s palsy and what effect does it have

A

acute unilateral inflammation of facial nerve
= pain behind ear
= paralysis of facial muscles
= failure to close eye

252
Q

what are the vestibular apparatus

A

connected series of endolymph filled membranous tubes that also connect with cochlear duct = contain hair cells
= 3 membranous semi-circular canals
= 2 saclike swellings = utricle/saccule

253
Q

what is the role of the hair cells of the vestibular system

A

detect changes in motion and position of head

only acceleration/deceleration

254
Q

how do the semi-circular canals detect motion in the head

A
  1. movements = semicircular canals move, endolymph does not
  2. moving cupula pushes against endolymph
  3. stereocilia on cupula bend = iron channels open
  4. glutamate released = vestibular branch of CNVIII
255
Q

what does the utricle respond to

A

tipping head away from horizontal plane e.g. tying shoelace

256
Q

what does the saccule respond to

A

from lying to standing/vertical acceleration

257
Q

what is the central auditory pathway

A 
cochlear nuclei 
to superior olivary nucleus 
to inferior colliculus 
to medial geniculate body of thalamus via inferior brachium nerve 
to primary auditory cortex
258
Q

what is the role of the superior olivary nucleus

A

has fibres that leave brainstem in vestibulocochlear nerve and end in tympanic membrane = inhibitory function

259
Q

what does I’MAuditory mean

A

inferior colliculus to medial geniculate body = auditory information
SO
superior colliculus to lateral geniculate body = visual information

Phase 1 mine (12 decks)

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