Motor System

Question 1

where are the cell bodies of upper motor neurones found

Answer 1

in the motor cortex of the pre-central gyrus

Question 2

what are the 2 functions of the UMNs

Answer 2

• directly excite LMN

- indirectly inhibit LMNs through interneurones

Question 3

what is the net effect of UMN - is it excitatory or inhibitory on the LMNs

Answer 3

inhibitory

Question 4

what is the corona radiata

Answer 4

bundles of radiating fibres making up the white tissue through which the axons of the UMNs travel through

Question 5

at which point do the fibres making the corona radiata get much closer

Answer 5

internal capsule

Question 6

what is the internal capsule

Answer 6

the space between the thalamus and the lentiform nucleus

Question 7

describe the pathway of the UMNs which synapse with spinal nerves

Answer 7

descend through the corona radiata, through the internal capsule, cerebral puduncle, non, medullary pyramids and then descends and synapses at the ventral horn

Question 8

where the the UMN decussate

Answer 8

at the medially pyramids

Question 9

what is the name of the tract which UMN descend through to synapse with spinal nerves

Answer 9

coritcospinal tract

Question 10

which side of the face do the UMNs suppling the upper face project

Answer 10

contraleterally and ipsilaterally

Question 11

which side of the face do the UMNs suppling the lower face project

Answer 11

contralaterally only

Question 12

what is the name of the tract for the UMNs involved with the facial nerve

Answer 12

corticobulbar tract

Question 13

what are the signs of damage to the UMNs

Answer 13

weakness
hyperreflexia
hypertonia
extensor plantar reflex

Question 14

what is spinal shock

Answer 14

this is where immediately after UMN damage the LMNs shut down so you get signs of LMN damage. however the LMNs gradually begin to work again so thats when you develop signs of a UMN damage

Question 15

what are the signs of LMN damage

Answer 15

weakness
areflexia 
hypotonia 
muscle wastage 
fasciculation

Question 16

why is muscle wastage seen in a LMN lesion

Answer 16

as the LMNs supply trophic factors such as growth factors to their target muscles

Question 17

what are the functions of LMNs

Answer 17

muscle contraction

spinal reflexes

Question 18

where is the cell body of a LMN found

Answer 18

either in the ventral horn or motor-nuclei in the brainstem

Question 19

what do the 3 cerebellar peduncles attach to

Answer 19

superior attaches to the midbrain
middle attaches to pons
inferior attaches to the medulla

Question 20

does cerebellar damage cause contralateral or ipsilateral symptoms

Answer 20

ipsilateral

Question 21

what are the causes of cerebellar damage

Answer 21

tumour, alcohol, stroke, MS, epilepsy medication

Question 22

how can cerebellar injury cause hydrocephalus

Answer 22

lesions of the vermis can extend to compress the 4th ventricle

Question 23

what are the symptoms of cerebellum damage

Answer 23

dysdiadochokinesis 
ataxia 
nystagmus 
intention tremor 
slurred speech 
hypotonia

Question 24

what is the basal ganglia

Answer 24

a group of structures in the brain which help to coordinate and control motor function

Question 25

what makes up the lentiform nucleus

Answer 25

putamen, globus pallidus externa and interna

Question 26

what makes up the striatum

Answer 26

putamen and cordate nucleus

Question 27

what makes up the substania nigra

Answer 27

pars compacta and pars recticularis

Question 28

where in the basal ganglia are dopamingeric neurones found

Answer 28

pars compacta of the substania nigra

Question 29

what does the direct pathway of the basal ganglia do

Answer 29

allows for movement due to stimulation of the motor cortex

Question 30

what happens to the direct pathway of the basal ganglia in the presence of dopamine

Answer 30

there is increased stimulation of the motor cortex

Question 31

what does the indirect pathway of the basal ganglia do

Answer 31

inhibits the stimulation of the motor cortex preventing movement

Question 32

what happens to the indirect pathway of the basal ganglia in the presence of dopamine

Answer 32

it will then promote the stimulation of the motor cortex to allow for movement

Question 33

what is motor neurone disease

Answer 33

a degenerative disorder affecting both upper and lower motor neurones

Question 34

what are the causes of motor neurone disease

Answer 34

most are sporadic but can also be familial

Question 35

what is Huntington's disease

Answer 35

a progressive neurodegenerative disorder where there is cell loss in the striatum of the basal ganglia

Question 36

which pathway of the basal ganglia is affected in Huntington's disease

Answer 36

indirect - however, as the disease progresses it can also affect the direct pathway

Question 37

what are the symptoms of huntingtons disease

Answer 37

chorea, dystonia, incoordination and cognitive decline

Question 38

what is hemiballismus

Answer 38

where there is damage to the subthalamic nucleus resulting in abnormal unilateral movement

Question 39

which pathway of the basal ganglia is affected in hemiballismus

Answer 39

indirect

Question 40

what usually causes hemiballismus

Answer 40

sub-cortical stroke

Question 41

what is parkinsons disease

Answer 41

where there is progressive degeneration of the substania nigra resulting is a dopamine deficiency

Question 42

what are the features of parkinsons disease

Answer 42

``` resting tremor bradykinesia hypertonia shuffling gait dementia ```