Neurobiology Theme 3 Flashcards
(377 cards)
1
Q
what are the types of sensory receptors in the skin
A
hair follicle receptors free nerve endings meissner corpuscle merkel cells pacinian corpuscle ruffini endings
2
Q
what are hair follicle receptors
A
sense motion, direction
fibre type II (a beta)
small receptive field
uncapsulated
3
Q
what are free nerve endings
A
nociception III ( adelta) & IV (cfibres)
4
Q
what are meissner corpuscles
A
tap, flutter
fibre type II ( a beta)
small receptive field
encapsulated
5
Q
what are merkel cells
A
touch, pressure
fibre type II (a beta)
small receptive field
unencapsulated
6
Q
what are pacinian corpuscles
A
vibration
type II (a beta)
large receptive field
encapsulated
7
Q
what are ruffini corpuscles
A
skin, stretch (slippage)
fibre type II (a delta)
large receptive field
encapsulated
8
Q
what type of threshold do skin receptors usually have
A
low
except for nociceptors which have high
9
Q
what is sensory transduction
A
conversion of a sensory stimulus from one form to another
10
Q
describe signal transduction on the pacinian corpuscle
A
pressure on skin changes shape of pc stretching na channels so na influx.
depolarisation, more +ve inside cell.
only when threshold is reached AP is propagated (generator potential)
11
Q
what type of action potential do sensory receptors generate
A
tonic- steady and constant firing
12
Q
how can we tell between light and touch
A
changes in firing rate- increase in tonic firing
duration of time for AP
activation of different receptive fields
13
Q
what is the difference between rapid and slow adapting receptors
A
rapid will respond to the application and removal of stimulus & fail to respond to a maintained stimulus
slow will increase firing rate if stimulus increased
14
Q
what are some ex of rapid adapting receptors
A
meissner corpuscle
hair follicles receptors
pacinian corpuscle
15
Q
what are some ex of slow adapting receptors
A
merkel cells
hair follicle receptors
ruffini corpuscles
16
Q
what is the receptive field
A
space occupied by a sensory receptor that can elicit a response to a stimulus (may be overlap)
different receptors have different sized receptive fields
17
Q
what would the receptive field be like on fingertips
A
small, numerous
more fields
highly discriminatory (can discriminate between 2 receptive fields)
18
Q
what would the receptive field be like on the back
A
large, sparse
low discrimination
19
Q
where is there a convergence of pathways in the body
A
rod of retina which signal to one bipolar neurone and one retinal ganglion cell can head to the brain
20
Q
what happens in divergence
A
one neurone can make many divergent connections to a number of post synaptic neurones
21
Q
what is the purpose of divergence and convergence
A
one sensory modality can alter the other like in the gated theory of pain
22
Q
in sensitive areas what happens to receptive fields
A
they overlap
23
Q
what is lateral inhibition
A
the ability of an excited neurone to reduce the activity of its neighbours
24
Q
what happens when there is stimulation of the centre of the field
A
the lateral aspects can also be stimulated
25
what happens to the lateral neurones when the centre neurone is central neurone is stimulated
they are inhibited by interneurones from the middle neurone
26
what does the brain receive in lateral inhibtion
info from the middle neurone to provide a more accurate and discriminative input
27
what are the two motorneurones in the ventral horn that innervate skeletal muscle
alpha motor neurones
| gamma motor neurones
28
specifically what the alpha motor neurones innervate
extrafusal muscle fibres
29
specifically what do gamma motor neurones innervate
intrafusal muscle fibres (within muscle spindle)
| spindle measures the degree of stretch tension within the muscle
30
what does the myotactic (stretch) reflex involve
- 1A afferents bringing back info from muscle spindle relating to the degree of stretch
- excite the flexor/extensor muscle that it is coming from
- inhibitory inter neurones will inhibit the activity of the opposite muscle being excited
31
where do preganglionic sympathetic axons arise and where do they go
lateral horn of the thoracic spinal cord and enter the sympathetic chain and synapse in the sympathetic ganglia
32
what is flaccid paralysis caused by
damage to lower motor neurones due to no innervation of the muscle it supplies so muscle will not work
33
what is spastic paralysis caused by
damage to upper motor neurones (e.g stroke, lesion i spinal cord) , lower motor neurones still active and under reflex control
34
what signals change in length in muscle spindle
1a afferents- stimulate muscle contraction
35
what signals change in tension in golgi tendon organ
1b afferents - inhibit muscle contraction
36
what will an increase in muscle length causes
activation of stretch and tendon(dampen down stretch reflex) reflexes
37
what is the central pattern generator
generation of alternate flexion and stretching during routine movements e.g. walking (within the spinal cord or brainstem)
38
the primary somatosensory cortex is the site for the termination of what pathway
thalamocortical
39
what does the primary somatosensory cortex contain
a topographical map of senses proportionate to the amount of sensory info
40
what are Brodmans areas 1,2,3
in the post central gyrus, compartmentalisation based on different functions
41
what is area 3b
primary somatosensory cortex
42
what is area 3a
proprioception
43
what is area 3b and 1
cutaneous stimuli
44
what is area 2
tactile and proprioception, size and shape
45
how is the post central gyrus organised
columnar organisation
46
what does the columnar organisation of the post central gyrus allow for
exact info from body areas to be extracted & processing of all info from nearby modalities
47
where is the secondary somatosensory cortex located
towards the end of the post central gyrus
| sup aspect is the lateral sulcus
48
what is the secondary somatosensory cortex involved in
higher order functions
- sensorimotor integration
- integration info from the 2 body halves
- attention, learning and memory
49
where is the association cortex for the primary somatosensory cortex located
posterior parietal cortex
50
what is the function of the posterior parietal cortex
integrate sensory info
| recognition of objects by touch
51
what does the lateral corticospinal tract do
voluntary control of distal musculature- trunk and limbs
52
why are movements from one side of the body controlled by the opposite cerebral cortex
corticospinal & corticobulbar tract originate in the motor area are the cerebral cortex but decussate to the other side of the brainstem
53
what does the anterior corticospinal do
voluntary control of proximal musculature (either under voluntary or unvoluntary control) - trunk and limbs
54
what do the reticulospinal tracts do
from pontine and medullary reticular formation into the spinal cord
regulate flexor reflexed and initiate patterned activity e.g. locomotion, swallowing
55
what to rubrospinal tracts do
red nucleus
| motor control, excitation of flexor muscles
56
which tract is the red nucleus apart of
rubrospinal
| regulates ongoing movement
57
where does the tectospinal tract run from
sup & inf colliculus in the tectum to cervical region of spinal cord
58
what is the role of the tectospinal tracts
orientation to auditory and visual stimuli
| control head movements in response to visual stimuli
59
where does the vestibulospinal tract run from
vestibular nucleus to the spinal cord
60
what do the lateral & med vestibulospinal tract do
lateral- controls antigravity muscles- balance
| medial- regulates head movements
61
what are upper motor neurones
those found in the cerebral cortex
62
what are the 2 ways UMN can project to LMN
directly or indirectly
63
how can UMN project directly onto LMN
corticospinal or corticobulbar tracts
64
what can damage to direct pathways cause
babinski sign: paralysis, paresis (weakness) of fine skilled movements
65
why do segmental reflexes remain unaffected when there is damage to the direct pathways
local reflexes still present
| only descending pathways damaged
66
what are the indirect pathways that UMN can project onto LMN
brainstem nuclei to LMN
- rubrospinal tract
- vestibulospinal tract
- tectospinal tract
- reticulospinal tract
67
what is the role of the indirect pathways of projection
integrate supporting musculature during voluntary movements & facilitate spinal reflexes involved with balance, posture eqm etc.
68
where does the lateral corticospinal tract decussate
medulla-spinal cord junction.
| it innervates the LMN on the other side
69
where does the anterior corticospinal tract decussate
at the segmental level in the spinal cord
70
where is the internal capsule located
between basal ganglia and thalamus
71
what passes through the internal capsule
corticospinal and corticobulbar fibres
72
how is the internal capsule organised
segmented to receive fibres from different limbs and part of the face
73
what type of stroke affects the internal capsule
lacunar stroke- this can take out the corticobulbar/corticospinal fibres
74
what does the tectum consist of
sup and inf colliculi in the midbrain
75
what is the reticular formation
all the neurones in the pons/medulla that are not in a specific nuclei or axons not in a particular pathway
76
what does the reticular formation contain
many nuclei and fibres travelling to cortex that release neuromodulators such as AchCh, serotonin and nor adrenaline
77
what is the function of the reticular formation
```
regulate cranial nerve activity
slow pain conduction and modulation
voluntary movements
autonomic nc activity
distribution of monoaminergic and cholinergic pathways
respiration
sleep
cerebral cortical arousal and wakefulness
```
78
where does the reticular formation spread from
pons to spinal cord
79
where do reticulospinal and vestibulospinal pathways originate from
brainstem
80
why does the vestibulospinal tract control the same side of the body
the cerebellum controls the same side of the body and the vestibular nucleus is linked to the cerebellum
81
what is the babinski sign
upper motor neurone lesion leading to damage to descending corticospinal pathways, stroking the sole of the foot causes an abnormal fanning of the toes and the extension of the big toe
82
what is the function of general somatic afferent fibres (GSA)
general sensation (from skin, skeletal muscle, joints and bone)
83
what is the function of special somatic afferent (SSA)
vision hearing and balance
84
what is the function of general visceral afferent (GVA)
visceral organs- info from visceral organs e.g in the vagus from the stomach
85
what is the function of special visceral afferent (SVA)
taste, visceral sense
86
what is the function of special visceral efferent (SVE)
skeletal muscle from branchial arches typically muscles of facial expression/mastication
87
what is the function of general somatic efferent (GSE)
skeletal muscle from somites (eyes and tongue
88
what is the function of general visceral efferent (autonomic) ? (GVE)
parasympathetic to smooth muscles and glands
89
which cranial nerves entirely sensory
I II and VIII
90
which cranial nerves are entirely motor
III, IV, VI, XI and XII
91
which cn are both sensory and motor
V, VII, IX and X
92
which 4 cranial nerves carry parasympathetic preganglionic fibres
III, VII, IX and X
93
what are the general somatic efferent (GSE) nuclei- motor
oculomotor
trochlear
abducent
hypoglossal
94
generally, where are the general somatic efferent nuclei (GSE)
close to the midline
| closest to the alpha motor neurones of the spinal cord
95
what do the oculomotor nerve innervate
superior, inferior & medial rectus, inf oblique & levator palpebrae superioris
96
what does the trochlear nerve innervate
sup oblique
97
what does abducent nerve innervate
lateral rectus
98
what does the hypoglossal nerve innervate
muscles of tongue
99
where is the oculomotor nuclei found
midbrain nearest midline
100
where is the trochlear nuclei found
midbrain nearest midline
101
where is the abducent nuclei found
pons nearest midline
102
where is the hypoglossal nuclei found
medulla nearest midline
103
what are the special visceral efferent nuclei (SVE) - motor
trigeminal
facial
nucleus ambiguous
104
what is nucleus ambiguous
the motor nuclei of IX, X, XI
| all the fibres that run in these nerves originate from this single nucleus
105
what does the motor trigeminal supply
Muscles of mastication, tensor tympani, tensor palitini, mylohyoid, ant, belly of digastric
106
what does the motor facial supply
Muscles of facial expression, post. belly of digastric, stylohyoid and stapedius
107
what does the motor nucleus ambiguous supply
Skeletal m. of pharynx, larynx and soft palate
108
where is the motor trigeminal nucleus
pons
109
where is the motor facial nucleus
pons
110
what are the general visceral efferent (motor) nuclei - parasympathetic
edinger-westphal nucleus
super salivatory nucleus
inferior salivatory nucleus
dorsal nucleus of the vagus n
111
where is the edinger westphal nucleus
midbrain
112
where is the superior salivatory nucleus
pons
113
where is the inferior salivatory nucleus
medulla
114
where is the dorsal nucleus of the vagus
medulla
115
what does the edinger-westphal nucleus supply and via what cn
III
| Sphincter pupillae and ciliary muscles
116
what does the Superior salivatory nucleus supply via what cn
VII
| Submandibular, sublingual and lacrimal glands
117
what does the inferior salivatory nucleus supply via what cn
IX
| Parotid gland
118
what does the dorsal nucleus of vagus n. supply
Many cervical, thoracic and abdominal viscera
119
where do all the parsympathetic fibres of the vagus originate
dorsal motor nuclues of the vagus
120
what are the general somatic afferent (GSA) nuclei
mesencephalic nucleus of V
chief sensory nucleus of V
spinal nucleus of V
121
which nuclei does proprioception muscle spindle relflex, spindle afferents enter
mesencephalic nucleus of V
122
which nucleus does fine touch (discriminative) enter
chief sensory nucleus of V
123
which nucleus does pain and temp from face enter
spinal nucleus of V
124
what are the special somatic afferent nuclei (SSA)
vestibular and cochlear nuclei
125
what is the General and special visceral afferent nucleus (SVA)
nucleus of solitary tract
126
what sensation does the nucleus of the solitary tract receive and from what cn
VII- taste from anterior 2/3 of tongue
IX- taste from posterior 1/3 of tongue
X- taste from epiglottis
127
what are the the 2 major places strokes can occur
cortical stroke- blood supply to the cortex from the carotid artery and middle cerebral (face and arms)
lacunar stroke- affects internal capsule area (more devastating)
128
what is the early neural tube surrounded by
alar and basal lamina
129
what does alar lamina develop into
dorsal horn- sensory - lateral
130
what does the basal lamina develop into
ventral horn- alpha
| motor neurones- medial
131
Where do corticobulbar fibres run from ?
cortex to the cranial nerve nuclei
132
What is the innervation of lower motor neurones ?
cranial nerve nuclei
133
What is the innervation of V and VII ?
bilateral projections from the primary motor cortex - upper face
134
What is the innervation of VII - lower face ?
contralateral
135
What is the innervation of XI ?
ipsilateral from PMC
136
What is the innervation of II , IVand VI ?
contralateral innervation from frontal and parietal eye fields
137
What is the innervation of XII ?
bilateral from PMC except for genioglossus - contralteral
138
Where does the trigeminal carry pain afferent run from ?
face, nose , orbit , meninges and muscles of mastication
139
Where does the facial nerve carry pain afferents from ?
ear and the canal
140
Where does the vagus nerve carry pain afferents from ?
meninges , ear canal and the larynx
141
Where does the glossopharyngeal carry pain afferents from ?
posterior tongue and pharynx
142
Where do the cervical spinal nerves carry pain afferents from ?
neck , meninges in the psoterior cranial fossa
143
Where are the sensory neurone cell bodies of the trigeminal found ?
in the trigeminal ganglion
144
Where are the proprioception cell bodies of the trigeminal found ?
mesencephalic nucleus of V
145
What does the spinal nucleus of V receive information about ?
firm touch , pain and temperature from skin of the face , oral and nasal cavities and palate
146
What does the main nucleus of V receive information from ?
fine touch from skin of face , oral cavity and palate
147
What information does the mesencephalic nucleus of V receive ?
proprioception from muscles of head
148
Where are the sensory neurone cell bodies ?
geniculate ganglion
149
Where do the general somatic afferents in the facial nerve come from ?
skin of the ear , ext.auditory meatus to spinal nucleus of V in medulla
150
Where are the sensory neurone cell bodies of the vestibulocochlear nerve ?
vestibular and spiral ganglia
151
Where are the somatic sensory neurone cell bodies of the glossopharyngeal nerve ?
superior ganglion
152
Where are the visceral sensory neurone cell bodies ?
petrosal ganglion
153
Where does the glossopharyngeal bring general somatic afferents from ?
firm touch , pain and temperature from posterior third of the tongue , oropharynx , nasal cavity and paranasal sinuses to the spinal nucleus of V
154
Where are the somatic sensory neurone cell bodies of the vagus ?
jugualr ganglion
155
Where are the visceral sensory neurone cell bodies of the Vagus ?
nodose ganglion
156
Where does the vagus carry general somatic afferentss from ?
firm touch , pain and temperature from the ear and external auditory meatus and mucous membrane of the larynx to the spinal nucleus of the V
157
What is the plexus of Raschkow ?
a central plexus in the pulp of the tooth - pain from teeth is mediated through this
158
What type of pain do A-fibres transmit ?
rapid and sharp pain
| belong to the myelinated group
159
What can A-fibres end branches to ?
odontoblastic processes located on the periphery of the pulp and dnetinal tubules
160
Where are A-fibres located ?
on the periphery of the pulp
161
What may trigger pain sensation in the teeth ?
fluid movement in the dentinal tubules
162
What type of pain is conducted by C-fibres ?
dull aching pain
163
Are C-fibres myelinated or unmyelinated ?
unmyelinated
164
Where do C-fibres terminate ?
in the pulp proper as free nerve endings or branches around blood vessels
165
What is the route of A and C fibres ?
run in the branches of V2 and V3 and then terminate in the spinal nucleus of V - passing to the thalamus and cortex
166
Where is pain associated with emotional distress processed ?
anterior cingulate cortex
167
Where is the periaqueductal grey matter located ?
around the cerebral aqueduct in the tegmentum of the midbrain
168
What does the periaqueductal grey matter do ?
plays a role in the descending modulation of pain
169
What neurones are found in the periaqueductal grey ?
enkephalin releasing neurones
170
What do enkephalin releasing neurones do ?
suppress pain
171
What is released from the raphe nuclei ?
serotonin
172
What does serotonin do ?
descends to the dorsal horn of the spinal chord where it forms excitatory connections with inhibitory interneurones in laminae II
173
When activated what do the interneurones do ?
release enkephalin
| binds to opioid receptros - descending pain modualtion
174
What is the corneal reflex ?
touch cornea with a cotton wisp which elicits the bilateral blink reflex
175
What is the pathway of the corneal reflex ?
sensory input from V1 - spinal nucleus of V - facial motor nucleus - orbicualris oculi
176
What is the gag reflex ?
touching the back of the oropharynx elicits brief elevation of the paate and brief constriction of the pharyngeal constrictors
177
What is the pathway of the gag reflex ?
sensory input from the glossopharyngeal - nucleus of solitary tract - nucleus ambiguus - vagus to the pharyngeal constrictors
178
What is the jaw jerk reflex ?
tapping on the chin leads to contraction of masseter and jaw closing
179
What type of reflex is the jaw-jerk reflex ?
monosynaptic
180
What is the pathway of the jaw-jerk reflex ?
chewing against resistance builds up tension in the PDL
unloading of stretch inhibits masseter
golgi tendon organ detects level of stretch in PDL , pressure is released and inihbits contraction of masseter
181
Which 3 cortices can pain pathways synapse in ?
nsular cortex
somatosensory cortex
anterior cingulate cortex
182
What is the spinal nucleus of V continuous with ?
dorsal horn of the spinal chord
183
Where is the primary visual cortex ?
occipital lobe - either side of the calcarine sulcus
184
Where does light first hit ?
retinal ganglion cells
185
How do impulses tavel from the retina to the bvrain ?
sensory neurones
186
What does the retina consist of ?
pigmented epithelium
| rods and cones
187
Where are the cones situated ?
fovea
188
Where are the rods sitted ?
peripheries
189
How do the rods synapse ?
many rods synapse on one bipolar sensory neurone - more sensitive to lower light
190
How do cones synapse ?
cones synapse on one bipolar neurone providing higher resolution
191
What are the membraneous discs ?
thye contain proteins that respond to light - rods contain rhodopsin and cones contain photopsin
192
What is the disinhibition of bipolar neuroness ?
light hits photoreceptors leading to hyperpolarisation which stops the release of neurotransmitter
193
Where does the optic nerve travel ?
through the optic canal
194
What is the pathway of the optic nerve ?
passes through the optic tract and the optic chiasm to the thalamus
195
Where in the thalamus does the optic nerve pass to ?
lateral geniculate nucleus
196
Alternatively where does the optic nerve pass to ?
superior calliculus
197
What are the 4 cranial nerve nuclei that control the movements of the eye ?
edinger- westphal nucleus
oculomotor nucleus
abducens nucleus
trochlear nucleus
198
What does the edinger westphal nucleus supply ?
ciliary muscle and the iris muscle
199
What is the papillary light reflex ?
light shone in one eye - contraction of both pupils - direct light reflex
contraction if the pupil oppsote leads to consensual light reflex
200
What is the accomodation relfex ?
focus on the incoming object leads to pupillary constriction- convergence of eyes as eyes focus on the near object
201
What is the pathway of the pupillary light reflex ?
light comes into the retina and the retinal gnaglion cells
travel via the optic tract to the lateral geniculate nucleus and the superior colliculi
bilateral innervation of the edinger westphal nucleus
output to the pupil and ciliary nucleus - contraction of the pupils
202
What is the pathway of the accomodation relfex ?
information travels tothe primary visual cortex
| bilateral innervation of the oculomtor (eye muscles) and edinger westphal nucleus (eye focus)
203
Where is the primary auditory cortex located ?
in the superior tempora; gyrus
204
How are action potentials triggered in the ear ?
pressure waves in the ear are conducted through the inner and middle ear
vibrations are caused in the tympanic membrane
generates waves of fluid on the cochlear
triggers hair cells to move
opens mechanically gated ion channels
triggers action potentials
205
What does the cochlear consist of ?
```
semi circular canals
utricle
sacculae
ampullae
cochlea nerve
```
206
What is the organ of corti ?
between the scala vestibuli and the scala tympani
| has a tectoriul and basilar membrane
207
What does the sensory ganglion contain ?
sensory cell bodies of the cochlea nerve
208
What does the sound on the tympanic membrane cause ?
sound hits the ossicles and causes vibration of the endolymph in the cochlea
generates vibrations in the basilar membrane
rubs in the tectorial membrane
moves the hair cells on the organ of corti
opens up channels and triggers APs.
209
What is the action of stapees ?
vibrates on the oval window
210
What is the helicotrema ?
a gap at the end of the unravelled cochlea allows fluid to move constantly
211
High frequency sounds are picked up by what ?
proximal end of the cochlea
212
Low frequency sounds are picked up by what ?
distal end of the cochlea
213
Which hair cells are sensory ?
95% of inner hair cells
214
What is the role of the outer hair cells ?
receive efferents from the superior olive
| modulate basilar membrane motions
215
What are sterocilia ?
organ of corti hair cells
216
What are present on hair cells ?
potassium ion channels - linked mechanically
217
Moving hair cells side to side causes what ?
physically opens the potassium channels and triggetrs voltage sensitive calcium channels - calcium cascade - vesicle movement and fusion with the presynaptic membrane
218
Desribe the auditory pathway ?
1st order neurones from receptors in the organ of corti , fibres synapse in the cochlear nuclei
2nd order neurones travel to the medial geniculate nucleus of the thalamus via the superior olivary nucleus and the inferior colliculus
3rd order neurones travel to the superior temporal gyrus in a bilateral pathway
219
Describe the auditory stream ?
```
primary auditory cortex
association auditory cortex
wernickes area
arcuate fasciculus
brocas area
motor cortices
```
220
What are the roles of the auditory cortrex
processing of sound
receives information from the medial geniculate nucleus
tonotopic representation of frequencies- different parts of the cortex pick up different f requencies
221
What is the vestibular system concerned with ?
balance
222
What is the vestibular system ?
semi circular canals are fluid filled - bulges are called ampullae
hair cells are located at the ampullae
endolymph inside the semi circular canals moves via inertia
triggers hair cell movement
nerve cells are triggered
223
What are otolith organs ?
ear stones
224
What are the ear stones ?
utricle and the saccule
225
What is the sensory epithelium of the ear stones called ?
macula
226
What do the ear stones do ?
sense tilt and linear head motions
| respond to gravity and linear acceleration
227
Where are the otolith organs ?
in a gelatinous mucous on top of hair cells
228
What are the otolith organs made of ?
CaCo3 deposits
229
What is the effect on the otolith organs of moving backwards ?
gravity pulls stones backwards and this pulls on the hair cells triggering a response
230
Describe the vestibuLar pathway ?
information from the ampullae , utricle and saccule goes to the vestibualr nucleus
from here pathways go to the cortex (III, IC,VI) , spinal chord (vestibulospinal tract and cerebelllum (balance)
to enter the cortices the pathway is the medial longitudinal fasciculus
231
performance of voluntary movements requires ?
job/task identification
planning for the activity
performance
232
What are the 3 levels of motor control ?
motor areas of thee cerebral cortex
brainsntem
spinal chord
233
What are the roles of the motor areas of the cerebral cortex ?
issue sequential and parallel commands
change intensities of different patterns
modify timing
234
What are the roles of the brainstem ?
maintain axial tone for standing
235
What are the roles of the spinal chord ?
programmed , local pattern of muscle movement
| location of complex pattern of rhythmical and reciprocal motion
236
What are the cortices of the brain related to motor control ?
posterior parietal cortex
| primary motor cortex
237
What is the role of the posterior parietal cortex /
association and representation
| initiation , planning and thought of activities
238
What is the role of the primary motor cortex ?
corticospinal and corticobulbar fibres arise from here
239
What are the 2 loops from the posterior parietal cortrex ?
1 to basal ganglia
| 1 to pontine nuclei and the cerebellum
240
Describe the basal ganglia loop for planning , carrying out and modulating activities ?
from the posterior parietal cortex to the basla ganglia
| back through the thalamus to the pre motor cortex to the supplementary motor cortex and to the primary motor cortex
241
What do the basal ganglia store ?
patterned movements are stored , responsible for initiation and planning of movement
242
Describe the pontine nuclei loop for planning , carrying out and modulating movement ?
fibres from the posterior parietal cortex to the pontine nuclei to the cerebellar hemispheres through the deep cerebellar nuclei to the thalamus
from the thalamus to the pre motor cprtex , supplemnetary motor cortex and the primary motor cortexx
243
What does the cerebellum do in modifying movements ?
it looks at intended movement and the current position of the muscles and decides which muscles to move
244
What does the cerebellum receive input from ?
the inferior olive- proprioception information from muscles
245
What arises from the primary motor cortex ?
corticospinal and corticobulbar fibres that travel in the internal capsule
246
What does the paramedian midbrain reticular formation do ?
regulates walking
247
What do the pontine reticulospinal pathways do ?
control extensor lower motoneurones
248
What does the posterior parietal cortex produce ?
produces internal models of movement prior to the involvement of the premotor and motor cortices
249
What do the prefrontal areas do ?
decisions here are made about what action to take
integrates info
concerned with personality , reasoning and conscience
250
`What does the premotor area do ?
controls axial and proximal limb muscles in the initial phases of orientating the body and arm to a target
251
wha does the supplemnetary motro area do ?
execute stages of complex movements based on past experiences
252
What side of the body does the cerebellum control
ipsilateral side
253
What does the cerebellum consist of ?
vermis - central
folia - folds
flocularnodular lobe
deep cerebellar nuclie
254
What are the 4 deep cerebellar nuc,ei from lateral to medial ?
```
dentate nucleus
emboliform nucleus
globose nucleus
fastigial nucleus
interposed nucleus - some individuals have this - emboliform and globose
```
255
What are the 3 functional parts of the cerebellum ?
vestibulocerebellum
spinocerebellum
neocerebellum
256
What is the vestibulocerebellum ?
flocculo-nodular lobe and part of the vermis
257
What is the function of the vestibulocerebellum ?
posture and balance
input from the vestibular nucleus and the dorsal spinocerebellar tract
output to the vestibular nucleus
258
What is the spinocerebellum ?
vermis and the fastigial nucleus and the intermidiate part or cerebellar hemisphere , globose and emoboliform nuclei
259
What is the function of the spinocerebellum ?
updating ongoing movements
input from the primary motor cortex via pontine nuclei, DSCT, ASCT and olivary nucleus
output to red nucleus
260
What is the neocerebellum ?
lateral part of the hemisphere and the dnetate nucleus
261
What is the role of the neocerebellum ?
initiation and planning of movements , motor learning
inout from the posterior parietal cortex , inferioe olivary nuclue s
output to the premotor cortedx , supplemnetary moor area via the thalamus
262
What is the route for planning and prediction in the cerebellum ?
from the cerebral cortex to the dentate nucleus via corticopontine fibres back to the thalamus to the cerebral cortex
263
What is the route for modification of ongoing movement ?
from the inferior olivary nucleus to the interposed nucleus to the red nucleus and the rubrospinal tract
264
What is the input and output of the olivary nucleus ?
output as climbing fibres to opposite cerebellum
| input from cortex and spinal chord
265
What is the role of the olivary nucleus ?
plays a role in movement inititation and motor learning
266
How is a lesion in the vestibulocerebellum presented ?
staggering gat
267
How is a lesion in the spinocerebellum presented ?
ataxia
268
How is a lesion in the corticocerebellum presented ?
slow movement onset
269
What are the basal ganglia ?
```
caudate nucleus
putamen
globus pallidus
subthalamic nucleus
substantia nigra
```
270
What is the circuit of the basal ganglia ?
output from cortical areas involved in planning and execution of movement to the basal ganglia
output from the basal ganglia to motorrelay areas of the thalamus (ventral anterior and ventral lateral nuclei of the thalamus)
271
How do the basal ganglia act ?
act ispilaterally
272
What do basal ganglia tend to do ?
inhibit movements therefore lesions produce unwanted movements
273
What are the 2 circuits through the basal ganaglia ?
putamen ciruit- putamen - globus pallidus to the thalamus and the cortex
274
What is the role of the putamen circuit ?
subconscious execution of learned patterns of movement
275
What is the caudate circuit ?
cognitive planning of movement - feedback to cortex
276
What does the substamtia nigra do ?
releases dopamine into the putamen circuit which acts on D1 and D2 receptors
277
Describe the direct pathway ?
cells with D1 receptors are excited by dopamine released from the substantia nigra
release of dopamine increases inhibition of the globus pallidus
releases tonic inhibiion of the thalamus causing cortical excitation
increases movement and cortical activity
278
Which pathway is normally inhibited ?
indirect pathway
279
Describe the indirect pathway ?
cells with D2 receptors are inhibited by dopamine
increases inhibition of the globus pallidus
decreases inhibition of the sub thalamic nucleus
increases excitation of globus pallidus
increases inhibition of thalamus
reduces thalamic excitation of cortex
reduces cortical motor activity
280
What are hypokinetic disorders ?
insufficient direct pathway output
| excess indirect pathway output
281
What are hyperkinetic disorders ?
excess directly pathway output
| insuufficient indirect pathway output
282
How is chewing iniitated ?
by voluntary movement
| followed by a period of reflex activity
283
What do CPGS do in mastication ?
generate masticatory rhythms - alternative action of jaw openers and closers
284
Where are the CPGs for mastication ?
in the pontine reticular nucleus
285
Describe the process of mastication ?
food is taken in and rhythmic mastication is imitiated
receptors in the oral cavity monitor hardness
assess whether the food is fir for swallowing
adjust the activity if muscles by feedback to motor neurones , CPG and cerebllum
when bolus is appropriate swallowing is initiated
286
Describe the control of mastication ?
CPG in the pontine RF
activate s the pre motro neurones and the trigmeinal motro nucleus
sneds rhythmical signals to the maticatory muscles
sensroy signals feedback about the bolus to the RF and the trigeminal motro neucleus
287
Which receptors control masticatory force ?
periodontal ligament receptors
288
What do periodontal ligament receptors do ?
inhibit neurones in the trigmeinal motro nucleus via inihbitory interneurones
289
What is the limbic system ?
neuronal cicitry that controls emotional behabviour and motivational drivees
290
What does the anteiror conguakte gyrus do ?
emotional aspect of pain
291
Where is the hippocampus and what does it do ?
medial aspect of the temporal lobe and is involved in memory formation
292
What is the hypothalamus and what does it do ?
major part of the limbic system and controls internal body conditions - vegetative behavior and endocrine fucntions
293
What are the outputs of the thalamus ?
to the braisntem RF
anterior thalamus and the limbic portion of teh cerebral cortex
hypothalamic infindibulum - pituitary glands
294
What are the functions of the thalamus ?
sexual behaviour
endocrine function
homeostasis
295
What does the hypothalamus do in terms of endocrine function ?
neuroendocrine cells reelase hormones that act in the pituitary gland and this releases more hormones
296
Which part of teh hypothalamus is to do with sexdual behaviour in fmelaes ?
ventromedial hypothalamus
297
Which part of the hypothalamus is to do with sexual behaviour in males ?
preoptic region
298
How does the hypothtlmaus carry out temperature reguaktion ?
temeprature sensitive neurones in the preoptic area measure the core body temeprature of teh blood
reduced brain/blood barrier in the hypothalamus
repsonse- horemone production
activation of teh ANS
behavioural response
299
Which area of the hypothalmaus creates a thirst sensation ?
laterla hypothalamic area
300
Which nucleus of the hypothalamus controsl the excretion fo water into urine ?
supraoptic nucleus
301
Which ara regualtes hunger in the hypothalamus ?
lateral hypothalamic area
302
Which area of the hypothalamus creates a desire for food ?
satiety centre in the ventromedial nucleus
303
What area of the hypothalamus carries out GI activity ?
mammillary bodies
304
What is the orexigenic response ?
response to low glucose and the need to eat more food
305
What is the anorexigenic response ?
high nutrients - stop eating food like GI stretch , circadian rhythms
306
What does GI stretch do ?
inihibits te orexigenic response and excites the anorexigenic response
307
What are circadain rhythms ?
endodogenous entrainsble 24 hour rhythmicity
308
What nucleus are circadian rhythms controlled by ?
suprachiasmatic nuclei
309
Where is the amygdala located ?
below the hypothakmaus and i the inferior portion of the laterla ventricvle
310
What ae the fucntions of teh amygdala ?
emotional letrning and memeorty
fear and fear cinditioning
reward
311
What does activation of the amygdala lead to ?
indices fea anxiety and violence
312
What does deactivation of the amygdala lead to ?
incapable pof fear
313
How is the amygdala involved in emotional learning and memory ?
amygdala assesses the emotional significance of inputs
| much more likely to remember something with emotional significance
314
How is thye amygdala involved in fear and fear conditioning ?
amygdala and the medial temporal lobe are invollved in the mediating , acquisition and storage of fear and memory
315
What is the reward system for ?
liking and positive reinforcement
316
What are the important structures in the reward system ?
```
ventral tegmental area - origin
amygdala
nucleus accumbens
hippocampus
prefrontal cortex
```
317
What is the reticular formation ?
a complex group of neurones and nuclei in the brainstem
318
What are the afferent inouts to the RF ?
spinal chord
cranial nerves
cerebellum
forebrain
319
What are the efferent ouputs of the RF ?
spinal chord and cortex
320
What are the fucntiomns of the RF ?
```
sleep and consciousness
somatic motor cintrol - CPGs
cardiovascular control
pain modulation
habituation
```
321
What are the 4 nuclei of the reticualr acting syste, ?
locus coereleus
raphe nucleus
ventral tegmental area
basal forebrain - nucleus of meynert
322
Where are the dopaminergic pathways of the RF ?
Ventral Tegmental Area - mesocorticolimbic pathway
| and substantia nigra - dopamine to basal ganglia
323
Where are the serotonergic pathways ?
raphe nuclei and the nucleus raphe magnus
ascending pathways to the cortex
descending pathways to the spinal chiord - pain modulation
324
Where are the noradrenergic pathways ?
locus coereleus
325
Where are the cholinergic pathways ?
basal forebrain and nucleus of meynert
| to the hippocampus
326
When does rapid eye movement sleep occur ?
JUST BEFORE WE WAKE UP
327
Wehre is rapid eye movement sleep regulated ?
pontine RF
328
What is needed to prevent the acting out of ndreams ?
connections between the pontine RF and the spinal chord
329
What nuclei are involved in sleep ?
Arpahe nuclei
| dorsolaterla pontine RF
330
What are the motor effects if the reticular formation ?
meduallry reticulospinal tract - laterla
| pontine reticulospinal tract- medial
331
What is the function of the pontine RT ?
enhances antigravity muscles and reflexes of the soinal chord
helps maintain a standing posture by resisting the effects of gravity
332
What is the function of the medullary RT ?
liberates the antigravity muscles from reflex control
333
What is the collective fucntion of the reticulospinal fibres ?
modualte muscle tone
regualte psoture
participate in automatic reflexes involving extensor musculature
334
What are CPG s?
trigger the correct enets at the right time
| 2 processes occur and they interact sequentially
335
What are the repsiratory CPGs ?.
pontine respiratory group
| medullary respiratory group - DRG and VRG and the pre botzinger complex
336
What is the paccemaker theory of CPGs ?
self activating fibres that trigger events
337
What is the network theory of CPGs ?
VRG made of inspiratory and expiratory neurones
| reciprocal imnhibition
338
Main output from the basal ganglia is from where ?
globus pallidus
339
What are the receptor organs responsdibl;e for detecting vibrations in the basialr membrane ?
organ of corti and the ampullae
340
What are sensory projections on the hair cells known as ?
sterocilia
341
What are the receptor organs responsible ofr snesing baalnnce ?
ampullae
342
Where are the ampullae located ?
in the semi circular canals of the cochlea
343
Which nuclei in the brainstem does the ouput from the vestibular nucleus go to ?
nucleus of oculomotr , trochlear and abducens
344
What are the outputs of the supplementary motor cortex ?
primary motor cortex
reticular formation
cortocspinal and corticobulbar
345
Which area of the brain is responsible for making an internal model of move,ent when assessing movements ?
posterior parietal cortex
346
Which nuclei are responsible for adaptation of movement in response to external stimuli ?
red nucleus
| olivary nucleus
347
In huntingtons disease which of the basal ganglia are effected /
globus pallidus
348
Which of the nuceli are responsible for conbtrol of water excretion ?
supra optic nuclei
349
Where is the satiety centre which controls hunger ?
ventromedial nuclei
350
What are the 5 structures responsible for the reward system ?
```
ventral tegmental area
nucleus accumbens
hippocampus
amygdala
pre frontal cortex
```
351
What are thee nuclei of the reticular formation and what do thy release ?
nucleus of meynert- acetylcholine
nucleus raphe magnus/raphe nuckeus- serotonin
ventral tegmental area- dopmaine
locus coerleus- noradrenaline
352
What happens during rapid eye movement sleep ?
paralysis of voluntary mucle and active brain
353
What happens during non rapid eye movemnt sleppe ?
lowering of body temeratir
movement of muscles
lowering of heartr rate
354
How can you identify a ruffini corpuscle ?
highly branched
355
How can you identify a pacinian corpuscle ?
round
356
How can you identify a pacinian corpuscle ?
round
357
How can you identify merkel cells ?
individual cells
358
How can you identify a meissner corpuscle ?
bunch of cells
359
How can you identify hair follicle receptors ?
around the hair
360
What are the structural components of the cerebellum ?
vermis
intermdiate zone
cerebellar hemispheres
floculonodular lobe
361
What are the functional components of cerebellum ?
spinocerebellum
vestibulocerebellum
neocerebellum
362
What is the vestibulocerebellum ?
floculonodular lobe
| posture and balance
363
What is the neocerebellum ?
posterior lobe
| planning of movement
364
What is the spinocerebellum ?
anterior lobe
| monitoring of ongoing movements
365
brain stem nuclei pathway- reticular nuclei
sensory, premotor, sup motor --> reticular nuclei -> reticulospinal -> coordianted movement muscle e.g. running
366
brain stem nuclei pathway- vestibular nuclei
vestibular nerve, cerebellum -> vestibular nuclei -> vestibulospinal -> maintenance of upright posture
367
brain stem nuclei pathway- cortex
cortex -> potine nuclei -> cerebellum -> Precision and efficiecny
368
brain stem nuclei pathway- inferior olive
cortex, spinal cortex -> inferior olive -> cerebellum, spinal cord -> coordination learned movement
369
what are the the 3 routes of pathways in the folia via
deep cerebellar nucleus
pontine nucleus
olivary nucleus
370
what are the descending fibres that enter the pontine nuclei
corticopontine/bulbar/spinal
371
where do axons from pontine nucleus go
send mossy fibres to cerebellum and into opposite cerebellar cortex
372
where does olivary nucleus send climbing fibres from inputs of proprioception
to opposite cerebellar cortex
373
what and where are purkinje cells
in folia- they are highly branches dendritic cells
374
what fibres run through dendritic trees of purkinje cell
parallel fibres- (each one is info from a point in the cortex
375
what permits the purkinje cells to allow or not allow movement to happen
collisions of proprioceptive info in purkinhe cells wiht sampling from hte cortex
376
where do purkinje cells send output axons
deep cerebellar cortex
377
where does deep cerebellar nucleus send its axons
back across midline to thalamus(hemisphere) or red nucleus (vermis)
