sensory neuroscience Flashcards
(165 cards)
1
Q
why does the spinal cord need protecting
A
because it is soft tissue
2
Q
what protect the spinal cord
A
vertebral column and the meninges (outer dura, then arachnoid then pia mater)
3
Q
what is the space between 2 spaces filled with
A
CSF
4
Q
what carries the blood vessels that go over the surface of the cord and supply it
A
pia mater
5
Q
what does the epidural space contain and what is it between
A
contains oily fat and is between the dura mater and bone
6
Q
what ligament is either side of the cord and what is its function
A
dentate ligament. holds together the pia mater and arachnoid mater, prevents spinal cord moving backward and forward
7
Q
what is the dura mater continuous with?
A
epineurium of spinal nerve
8
Q
where does the spinal cord terminate
A
L1-2
9
Q
where can other nerve roots continue down to
A
L2-5
10
Q
What is the lumbar cistern
A
space below the tip of the spinal cord which contains spinal roots and is part of the subarachnoid space
11
Q
what is the cauda equina
A
nerve roots travelling through the lumbar cistern
12
Q
how many spinal cord segments
A
31
13
Q
what fissure contains the anterior spinal artery
A
midline fissure
14
Q
what is grey matter divided into
A
dorsal and ventral horn
15
Q
what is the white matter divided into
A
3 tracts- dorsal white column, lateral white column, anterior white column
16
Q
what is the white matter on either side connected by
A
white commissure
17
Q
what is the dorsal white column divided into
A
fasciculus gracilis (more medial) and fasciculus cuneatus
18
Q
is the dorsal horn motor or sensory
A
sensory
19
Q
what nuclei run in the dorsal horn of the grey matter
A
nucleus proprius and substantia gelatinosa
20
Q
what is the ventral horn
A
motor
21
Q
what are the 2 groups of motor neurones in the ventral horn
A
medial (in every segment) and lateral (only where the segments give rise to nerves forming the limb plexuses)
22
Q
what do the descending tracts synapse with in the white matter
A
with lower motor neurones
23
Q
does white matter decrease or increase as descends?
A
decreases as go down the descending tract some axons leave
24
Q
what are the ascending tracts
A
sensory
25
as they ascend what happens to the white matter
increases as gather more axons
26
what is in the middle of the grey matter
central canal which is a remnant of the ventricular system (contains CSF)
27
how does the dorsal horn change?
depends on how large/sensitive the area supplying it is eg small dorsal horn in thoracic region
28
how does the ventral horn change?
depends on how many motor neurones has to accommodate. at level of the limbs the lateral group push ventral horn into an oval shape
29
what can lead to sciatica and parasympathetic disturbances (cauda equine lesions)
the lumbar spine is flexible and lumbosacral nerve roots can be stretched, compressed or irritated
30
what is sciatica characterised by
pain, muscle wating, exaggerated tendon reflexes, urinary retention
31
a common cause of sciatica
slipped disc
32
C1-4
breathing
33
C2
head and neck movements
34
c4-6
HR
35
c5
shoulder movement
36
c7-t1
head and finger movements
37
t1-t12
sympathetic tone
38
t2-t12
trunk stability
39
t11-L2
Ejaculation
40
L2
hip motion
41
L3
knee extension
42
L4-S1
foot motion
43
L5
knee flexion
44
s2-s4
penile erection
45
s2-s3
bowel and bladder
46
where is the site of termination of afferents conveying senses of pain, temperature and touch?
substantia gelatinosa
47
what do the neurones of the nucleus proprius give rise to?
spinothalamic tracts
48
whats between the dorsal and ventral horns?
groups of interneurones
49
are the substantia gelatinosa and nucleus proprius in every segment?
yes
50
what is the lateral horn responsible for
preganglionic sympathetic outflow (only in thoracic and upper lumbar)
51
what do motor neurones in the medial group innervate?
muscles close to the midline (axial muscles)
52
what do motor neurones in the lateral group innervate?
limb muscles
53
where does the lateral division extend from to?
T1-L2/3
54
where is sacral parasympathetic outflow?
S2-S4
55
What is a nerve
made up of several roots
56
what are required for connecting of intersegments
fasciculus proprius; interneurons in gray matter running up and down; corticospinal fibres (from cortex); dorsolateral tract of Lissauer.
57
what is the fasciculus proprius
sheet of axons between the white and gray matter
58
what is the dorsolateral tract of lissauer
incoming afferent fibres come in and branch up and down by 1 or 2 segments
59
what is the dorsal column pathway for?
proprioception, discriminative touch and vibration
60
how does the primary neurone ascend in the DCP? (dorsal column pathway)
ipsilaterally
61
where does the primary neurone synapse in DCP?
at the medulla
62
where are the secondary neurone cell bodies in DCP?
in medullary nucleus gracilis and cuneatus
63
where is sensory decussation in DCP
after synapsing in the nucleus gracilis or cuneatus
64
where is the tertiary neurone cell body in DCP?
in the thalamus, travels to the primary cortex
65
after sensory decussation where does the pathway gather? (DCP)
in the medial lemniscus
66
where does it terminate in the thalamus (DCP)
ventral posterolateral nucleus of the thalamus
67
where does the pathway travel through (DCP)
internal capsule
68
where does the fasciculus gracilis carry information from
lower half of the body (below T6)
69
where does the fasciculus cuneatus carry information from
upper half of the body
70
where do the cell bodies of a sensory neurone lie
in the dorsal root ganglia
71
what channel type is present on dendrite like extension of the axon
stimulus gated channel
72
are stimulus gated channels all or nothing
no, graded response
73
if the generator potential is sufficiently large what happens
depolarise the adjacent membrane- open Na+ channels leading to an action potential
74
what do exteroceptors detect
information from outside environment- eg touch and temp, found mainly on the skin
75
what do proprioceptors detect
properties of the organism eg muscle and tendon reflexes
76
what are the slowest types of fibres (speed of conduction)
C fibres
77
what are the order from fastest to slowest of A fibres
A(alpha), A(beta), A(delta)
78
which fibres are well myelinated
A(alpha) and A(beta)
79
what do C fibres and A(delta) detect
C- pain, temp, itch; A(delta)- pain and temp
80
what do A(alpha) and A(beta) detect
A(alpha)- muscle proprioceptors; A(beta)- skin mechanoceptors
81
what do naked endings detect
pain, temp, touch
82
what are the encapsulated endings and what do they detect
Pacinian (vibration), Ruffini's (shear stress), Merkels (pressure), Meissners (touch)
83
which receptors are rapidly adapting
Pacinian corpuscle (Merkels- slow)
84
what is a consequence of nerves being compressed or damaged
conduction velocity falls
85
what is the dorsal horn of the spinal cord divided into
laminae
86
what do the laminae 1 and 2 make up?
substantia gelatinosa
87
where do A (beta) terminate (laminae)
laminae 2-5
88
where do A (alpha) terminate (laminae)
extend into the ventral horn to synapse with lower motor neurones
89
what tract is involved in posture and balance
spinocerebellar tract
90
what is an incomplete lesion
hemicord lesion (brown-sequard lesion)
91
what pathway is involved in posterior cord syndrome and what are the symptoms
dorsal column pathway. clumsiness, impaired proprioception, good muscle strength
92
what happens to limbs in their development
grow outwards and rotate
93
how do upper limbs rotate
laterally. thumb at end of pre axial border
94
how do lower limbs rotate
medially. big toe at end of post axial border
95
what roots supply biceps
C5-6
96
what roots supply triceps
C7-8
97
what motor supplies gluteal
L5-S1
98
motor supply to calf muscles
S1-2
99
what motor supply to pelvic floor, bladder etc
S3-5
100
what roots involved in finger flexion reflex
C7-8
101
what roots are involved in the knee reflex
L3-4
102
what roots are involved in ankle reflex
S1
103
what are the superficial reflex of epigastric
T7-9
104
superficial reflex of lower abdominal
T11-L2
105
superficial reflex of cremasteric reflex
L1-2
106
what is the superficial anal reflex
S4-5
107
what is a theory of referred pain
several nociceptors from several locations converge on a single ascending tract in the cord. pain signals from skin more common
108
where does the afferent input get confused in referred pain
dorsal horn
109
where does the pancreas refer pain to
back
110
where does liver and gallbladder refer pain to
tip of scapula
111
diaphragm, lung and spleen refer where
left shoulder
112
what information does the mandibular nerve also carry
proprioception
113
what does all info coming from the head pass via
trigeminal ganglion
114
after passing through the trigeminal ganglion where do the neurones go
1 of 3 ganglia (GSA trigeminal nuclei)
115
what tracts are associated with the trigeminal
trigeminothalamic tract
116
where does the trigeminothalamic tract run to and how
to the thalamus, bilaterally
117
what is the nucleus destination of the trigeminothalamic tract
ventral posteromedial nucleus of the thalamus
118
after the ventral posteromedial nucleus of the thalamus where does the information go
through internal capsule to the primary sensory cortex
119
what fibres are found in the anterior and posterior limbs of the internal capsule
thalamocortical fibres
120
what fibres are found in the post limb of the internal capsule
corticospinal and corticonuclear
121
what supplies the internal capsule (blood)
MCA
122
what supplies the anterior limb of the internal capsule
lateral and middle striate branches
123
what supplies the posterior limb of the internal capsule
anterior choroidal artery
124
what is the brodmanns area for primary motor cortex
4
125
what is the brodmanns areas for primary sensory cortex
1,2,3
126
how does the motor homunculus represent info
contralateral and inverted
127
where are the inferior parts of the body represented on the sensory homunculus
on medial surface (as move laterally and downward, move upwards on the body)
128
what information goes to area 3a (central sulcus)
muscle spindles
129
what info goes to area 1
from joints
130
where is all info transferred to from area 3
area 2
131
how does info relay from visual cortex to wernickes area
via angular gyrus
132
what connects wernickes and brocas areas
arcuate fasciculus
133
what is nociception
signals derived from tissue damage
134
what is pain
unpleasant sensation associated with nociception
135
what fibres are responsible for the first sharp localised pain
A delta
136
what fibres are involved in the long prolonged dull pain following the initial pain
C fibres (poorly localised)
137
what speed do C fibres carry
0.5-3m/s
138
what speed do A delta carry
5-30 m/s
139
what do all primary sensory neurones have as their excitatory neurotransmitter
glutamate
140
what is further released for pain to perceived as moderate- intense pain
substance P
141
what does substance P stimulate
histamine release leading to vasodilation and an inflammatory response
142
what other peptide is released by primary sensory neurone which aids in vasodilation
CGRP
143
what do mast cells release to activate nociceptors
5HT
144
what happens in primary hyperalgesia
histamine with prostaglandins and bradykinin increase the sensitivity of nociceptive sensory endings
145
what happens in chronic stimulation of nociceptors
build up of peptides in dorsal horn; increase in activity of neuronal responsiveness (wind up)
146
what is the wind up in activity of neuronal responsiveness due to
change in responsiveness of NMDA glutamate receptors, so NDMA antagonists are used in pain relief; also increase size of nociceptive receptive fields (inhibition of inhibitory neurones by substance P)
147
what is secondary hyperalgesia
central increase in pain sensitivity due to wind up in the activity of neuronal responsiveness
148
what is allodynia
touch sensitive sensory neurones (low threshold) start to generate sensation of pain
149
what is the gate theory of pain
some spinothalamic neurones receive inputs from both touch sensitive sensory neurones and nociceptors (which stimulate strongly). activation of the low threshold touch sensitive neurones blocks the nociceptors
150
what are some endogenous analegesics
endorphins, enkephalins
151
What neurotransmitter (monoamine) can inhibit the passage of nociceptive info?
5HT
152
What is somatic pain
within the body eg muscle, body
153
what happens in peripheral neuropathic pain
cut axons sprout but if blocked forms a neuroma which is hypersensitive
154
how do endorphins and enkephalins work?
prevent info transfer from nociceptors to sensory interneurons in the dorsal horn
155
what is a neuroma
tangled mass of neurones
156
what can neuromas be hypersensitive to
pressure and temperature
157
what can neuromas do to increase pain
change their phenotype to express alpha-adrenergic receptors, so if sympathetic axons release NA then pain arises
158
what does the spinothalamic pathway convey
pain, simple touch and temperature
159
what happens in the dorsolateral tract of Lissaeur (spino)
birfurcates, travels up/down by 1 or 2 segments
160
in the substantia gelatinosa, the branches make contact with secondary neurones from where? (spino)
nucleus proprius
161
where do the axons decussate in spinothalamic pathway
axons of nucleus proprius cross over
162
ascends in spinothalamic tract to synapse where
ventral posterolateral nucleus of thalamus
163
what tract brings proprioceptive info to the cerebellar cortex
spinocerebellar tract. from muscle spindle, tendon organs and joint capsules
164
what is the spinocerebellar tract important in
motor function, balance and posture, info on position of limbs
165
what is significant in the spinothalamic pathway
1 or 2 segments up or down from where the primary afferents entered
