L7 Flashcards

1
Q

what is the reticular formation composed of

A

Composed of clusters of gray matter scattered throughout

midbrain, pons and medulla

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is the role of the reticular formation

A

Its role is for arousal and it does this by the thalamus. (it sends its neurons to the thalamus)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is the reticular formation involved in

A

habituation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is habituation

A

a process in which the brain

learns to ignore repetitive, inconsequential stimuli while remaining sensitive to others

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is the reticular formation inhibited by

A

inhibited by sleep centres located in the hypothalamus & other brain regions

this is because when you are asleep you don’t want to be woken

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is the reticular formation depressed by

A

depressed by alcohol, sleep-inducing drugs &

tranquilisers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what would happen if you were to damage the brainstem

A

permanent unconsciousness
(irreversible coma) because this is where the reticular formation is therefore if that is damaged then you would be unable to be woken

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what % of neurons are in the cerebellum

A

50%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is the important functions of the cerebellum

A

balance and coordination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

where is the cerebellum located

A

in the posterior cranial fossa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is the dame of the 3 sections that the base of the skull is divided into

A

The base of the skull is divided into the anterior, middle and posterior cranial fissure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what structures is the cerebellum posterior to

A

the superior medullary velum ( the roof of the 4th ventricle)

and

the inferior medullary velum (chloride plexus)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what are the main structures of the cerebellum

A

cortex, white matter and deep nuclei

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what are the primary roles of the cerebellum

A

synchronised, precisely timed movement across
multiple joints = synergistic multijoint limb movement
Eg. throwing a ball, finger-to-nose test

control of muscle tone (posture)

maintenance of balance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

does the cerebellum give rise to conscious sensory perceptions

A

no

it receives vast amount of sensory information, but does not give rise to conscious sensory perceptions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

is the cerebellums role for afferent or efferent information

A

it has 40x more afferents than efferents. this is because of the vast amount of sensory information coming in

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

how is synergetic multi joint movement achieved

A

Frontal motor association areas (eg. premotor cortex)
via the corticopontine-cerebellar tract, inform cerebellum of intent to start voluntary muscle contractions

At the same time, the cerebellum receives information from proprioceptors throughout the body, as well as visual
and vestibular (balance) input

The proprioceptive information includes tension in muscles and tendons and the position of joints.

This information allows the cerebellum to evaluate body
position and momentum = where the body is and where it intends to go.

The cerebellar cortex and the deep cerebellar nuclei then calculate the best way to coordinate the force of each muscle contraction to prevent overshoot, maintain posture & ensure smooth coordinated movement.

Then, the cerebellum dispatches to the motor cerebral cortex its “blueprint” for coordinating movement. The primary motor cortex then influences motor neurons in the spinal cord to produce movement.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what structure do the neurons from the premotor cortex go through to inform the cerebellum that you want to start a movement

A

corticopontine-cerebellar tract

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

which structures calculate the best way to ensure smooth coordinated movement

A

the cerebellar cortex and deep cerebellar nuclei

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what would be expected if an individual had a cerebellar lesion

A

they are usually capable of
carrying out general outlines of movement, but each movement is executed with suboptimal coordination and precision.

they will be clumsy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what anatomy is needed to achieve synergistic multijoint movement

A

Cerebellum needs to be connected to the motor input from cerebral cortex, the various sensory inputs and needs to send its output or blueprint back to the cerebral cortex.

it also needs the cerebellar penuckle’s to connect one region of the brain to the other

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what are the names of the 3 cerebellar peduncles and where are they located

A

the superior cerebellar peduncle is located in the midbrain

the middle cerebellar peduncle is located in the pons

the inferior cerebellar peduncle is located in the medullar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

from what view would you see the cerebellar peduncles

A

an dorsolateral view of the brainstem

or

the anterior view of the cerebellum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what structures is the cerebellum posterior to

A

Brainstem, 4th Ventricle, Vela, Cerebellar Peduncles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
when looking at the anterior view of the cerebellum what do the peduncles look like
they are white because they are white matter tracts the superior on is the thin skinny bit the middle and the inferior are the circular bit. the middle is the circle bit closes to the superior cerebellar peduncle
26
what is a insisure
it is the equivalent of a sulcus in the cerebellum
27
how can you identify the anterior and posterior cerebellar incisures
anterior is the bit of the cerebellum that dips in where the brainstem is posterior is the bit that dips in at the middle back of the cerebellum
28
what do the anterior and posterior cerebellar incisures contain
the flux cerebelli
29
what are the right and left hemispheres of the cerebellum connected by
the vermis
30
what are the parallel surface folds of the cerebellum called
folia (leaves)
31
what do folia consist of
gray matter
32
what is the white matter in the cerebellum called
arbor vitae tree of life
33
where do the deep nuclei sit in the cerebellum
in the white matter
34
what are the main cells in the cerebellum
purkinje cell granule cell (has parallel fibers) mossy fibers climbing fibers
35
what plain do the dendrites of the purkinje cells sit in
caronal
36
what are two main inputs of the cerebellar circuits
mossy fibers and climbing fibers
37
what is the role of mossy fibers
mossy fibers/axons come from spinal cord or brainstem neurons and convey motor or sensory input to the cerebellum Mossy axons form excitatory synapses with granule neurons in the cerebellar cortex.
38
what is the role of climbing fibers
mainly from inferior olivary nucleus therefore they bring proprioceptive input. One ION neuron innovates 1 PC therefore this is a very precise system Climbing axons form excitatory synapses directly with the purkinje neurons/cells in the cerebellar cortex.
39
mossy fibers synapse with granule neurons. what happens from here
The granule neurons send their axon as a parallel fibre (because it is parallel to the surface) to form excitatory synapses with the Purkinje neurons.
40
what is the role of the purkinje cell
Purkinje neuron is sole output neuron of the cerebellar cortex. Is inhibitory. Works with input axons to regulate the firing frequency and amplitude of the neurons in the deep cerebellar nuclei = "blueprint" sent to motor cortex.
41
what is the role of the neurons in the deep cerebellar nuclei
they integrate synaptic output
42
what are they layers of the cerebral cortex
outer most to inner most molecular layer purkinje cells granule cell layer white matter
43
describe what a purkinje cell looks like
it has an oval shaped cell body in the granule cell layer elaborate flattened, fanlike dendrite tree (sagittal section)
44
what divides the cerebellum into the anterior and posterior lobe
the primary fissure
45
what is the name of the 3rd lobe in the cerebellum
flocculonodular lobe
46
what is the function of the lobes in the cerebellum
anterior and posterior lobes = coordination of movement flocculonodular lobe = balance
47
where is the flocculonodular lobe located
the inferior surface, deep to the vermis
48
what structures make up the flocculonodular lobe
the 2 flocculus and the nodulus
49
what is hydrocephalus effect on the tonsils
If you have increased intracranial pressure (hydrocephalus) then it will push the tonsils down which puts pressure on the medulla which is where the neurons for the heart and lungs are which means that if they are damaged then you will die
50
what are the sagittal functional subdivisions of the superior surface of the cerebellum
the lateral zone (the lost lateral part) the intermediate zone (middle) the median zone (vermis)
51
what are the 4 deep cerebellar nuclei
Fastigial Globose Emboliform Dentate
52
which of the 4 deep cerebellar nuclei from the Interposed/Interpositus Nucleus
Globose and Emboliform
53
which deep cerebellar nuclei does the vermis project to
the Fastigial nucleus
54
which deep cerebellar nuclei does the intermediate zone project to
the interposed/interpositus nucleus
55
which deep cerebellar nuclei does the lateral zone project to
the dentate nucleus
56
the Flocculonodular lobe can also be called the.....
= Vestibulocerebellum
57
what are the Cerebrocerebellar circuits responsible for
controls multijointed movements of limbs to create fluid and coordinated movement
58
what are the Spinocerebellar intermediate zone | circuits responsible for
controls accuracy of movement of the limbs. | eg. precision at a joint
59
what are the Spinocerebellar medial/median/vermal | zone circuit responsible for
Controls posture via influencing axial muscles in trunk
60
what are the Vestibulocerebellar circuits responsible for
maintain balance via axial and limb muscles
61
describe the pathway of the cerebrocerebellar circuits
the first thing that happens is the cerebral cortex tell the cerebellum what to do via the CPCT This is from the premotor cortex neurons inform the cerebellum what you want to do The neurons in the cerebrum to the pontine nuclei and then into the lateral zone of the cerebellum The spino-olivary tract comes up form the spine, crosses in the olive and then crosses to the lateral zone. This is proprioceptive information The PC cells then go to the deep cerebellar nuclei (dentate nucleus) which then send the blueprint back up to the motor cortex From there the movement gets sent down
62
describe the pathway of the spinocerebellar intermediate zone circuits
This time the CPCT goes to the intermediate zone no the lateral zone Even though this is called spine there is still CPCT input Sensory information comes up from the inferior olivary nucleus to the intermediate zone The PC innovate the interpositus neurons which create the blueprint This then gets sent through the red nucleus to the thalamus to motor cortex and leaves through the lateral corticospinal tract
63
describe the pathway of the spinocerebellar vermal zone circuit
Integrating information from the spinocerebellar tracts and the inferior olivary nucleus These go the the median zone of the deep cerebellar nuclei the PC cells innovate the visidual nucleus (the most medial). This goes to the thalamus and then to the PMC. It leave through the ventral corticospinal tract
64
describe the pathway of the vestibulocerebellar circuits
Input from the inferior olivary nucleus These are climbing and mossy fibers The mossy fibers are coming from the vestibular labyrinth (semi-circular canals) Both climbing and mossy fibers go via the inferior cerebellar peduncle to the pocculondualar lobe. From there the PC go directly with the vestibular nuclei to the vestibular spinal tract.
65
what is the role of the inferior cerebellar peduncle
conveys sensory information to the cerebellum from muscle proprioceptors throughout the body AND from the vestibular nuclei of the brainstem (equilibrium & balance) contains both afferent (chiefly) & efferent axons
66
what is the role of the middle cerebellar peduncle
contains only afferent axons (crossed axons from contralateral pontine nuclei). Eg CPCT
67
what are the characteristics of the superior cerebellar peduncle
formed by axons that arise from deep cerebellar nuclei (main efferent pathway) fibers decussate at various levels crossed fibers ascend - either terminate in the red nucleus or continue rostrally to end within the thalamus (then to cerebral motor cortex)
68
what does ipsilateral haf mean
same side
69
where does each cerebellar hemisphere excert its influence in the body
Each cerebellar hemisphere exerts its influence primarily on the ipsilateral half of the body this is because they are doubly crossed
70
what is ataxia
inaccuracy in the speed, force and distance of | movement (staggering gait, dysmetria, slurred speech)
71
what is a tremor
involuntary oscillation of the limbs or trunk
72
what is nystagmus
rhythmic involuntary oscillation of the eyes
73
what could be the cause of a headache and vomiting in relation to the cerebellum
this is often 1st symptoms of cerebellar tumour Tumor which blocks the CSF drainages from the 4th ventricle which increases the pressure causing a headache. The vomiting if from pressure on the medulla