voluntary movement

Question 1

what are the different types of movement?

Answer 1

• involuntary actions- reflexes
• semi-automatic
• voluntary

Question 2

describe semi-automatic movements

Answer 2

• voluntary but you dont have to think about them
• often repeated movement sequences
• appear stereotyped but very adaptable
• eg walking, breathing and chewing

Question 3

what are the projections off of the cell body of a neuron?

Answer 3

dendrites

Question 4

what are central packing generators?

Answer 4

collections of neurons which have a rhythmic output which influences motor patterns of muscle groups

Question 5

what are outputs of central packing generators?

Answer 5

effector organ

Question 6

what do effector organs allow?

Answer 6

• an individual to respond in different muscle groups
• have reflex feedback to monitor output

Question 7

what can CPGs be under control of?

Answer 7

higher control neurons
- central feedback loops regulate this

Question 8

what do sensory feedback systems do?

Answer 8

regulate the entire CPG system

Question 9

what are voluntary actions?

Answer 9

• self-initiated
• purposeful (goal directed)
• learned
• improved with practice
• adaptable

Question 10

where is the motor cortex?

Answer 10

anterior to central sulcus

Question 11

where is the primary sensory cortex?

Answer 11

posterior to central sulcus

Question 12

dorsal funiculus

Question 13

lateral funiculus

Question 14

ventral funiculus

Question 15

ventromedial funiculus

Question 16

what is the corticobulbar pathway?

Answer 16

the pathway of the recruitment of lower motor neurons than comprise cranial nerves

Question 17

where do the corticobulbar pathway neurons pass through?

Answer 17

• ## start from the upper motor neuron in motor cortex

Question 17

where do the corticobulbar pathway neurons pass through?

Answer 17

• start from the upper motor neuron in motor cortex
• through the basic pedunculi
• branches to innervate the distict motor neuron groups eg trigeminal/facialvagus/hypoglossal

Question 18

describe the corticospinal pathway

Answer 18

similar to the corticobulbar except the axons project much farther down the spine
- 85% axons cross over to the other side (pyramidal decussation)
- 15% cross over later

Question 19

where is the lateral corticospinal tract?

Answer 19

• 85% axons crossed over
• dorsal lateral finiculus

Question 20

where is the anterior corticospinal tract?

Answer 20

• 15% of axons crossed over later
• ventral medial finiculus
• only projects to the mid-thoracic level

Question 21

where do pathways to motor neurons controlling distal muscles (hands, feet, lower face, tongue) originate from?

Answer 21

opposite side of the brain

Question 22

what do pathways to motor neurons controlling the upper face receive?

Answer 22

bilateral descending cortical commands

Question 23

what is the difference between initiating a normal movement vs a reflex?

Answer 23

• normal movement involves an upper motor neuron
• reflexes come from spine to lower motor neuron

Question 24

what happens if we damage an upper motor neuron?

Answer 24

- no voluntary movement

Question 25

how could an upper motor nueron become damaged?

Answer 25

stoke/trauma

Question 26

how could a lower motor neuron become damaged?

Answer 26

peripheral nerve injury

Question 27

what happens if a lower motor neuron is damaged?

Answer 27

no movement can occur as the muscle cant be activated

Question 28

what is bells palsy?

Answer 28

- loose capacity to engage and contract muscles of facial expression innervated by the facial nerve - would typically dissipate within two weeks

Question 29

how can a refined motor system be achieved?

Answer 29

involving other subcortical regions such as the thalamus and basal ganglia which can directly influence upper motor neurons and also the circuits within the spinal cord

Question 30

where do the additional descending motor projections arise from?

Answer 30

various areas of the cerebrum and brainstem eg the basal ganglia arises from the cerebellum and brainstem

Question 31

what is the function of the additional descending motor projections?

Answer 31

- to co-ordinate movements - help maintain posture/balance - help integrate actions of several muscles

Question 32

what are the basal ganglia?

Answer 32

- compromised of several interconnected sub-cortical nuclei - link to the cerebral cortex via feedback loops - influence/regulate output from the motor cortex - act to initiate actions and to switch from one action to another

Question 33

what is the function of the internal capsule?

Answer 33

responsible for the relay of information from the spinal cord/brainstem via the thalamus to the sensory cortex OR the descend projections of axons from upper motor nuerons to the cortical bulba or cortical spinal pathways

Question 34

what is the function of the ventricles?

Answer 34

come together with the white matter systems allowing us to identify the anitomical position of the basal ganglia

Question 35

body caudate nucleus

Question 36

putamen

Question 37

globus pallidus

Question 38

thalamus

Question 39

substantia nigra

Answer 39

- specled

Question 40

what comprises the basal ganglia?

Answer 40

body caudate nucleus putamen globus pallidus thalamus substantia nigra

Question 41

what are the three action selection centres of the basL ganglia?

Answer 41

- corpus striatum - sub-thalamic nuclei - substantia nigra

Question 42

what comprises the corpus striatum cente of the basal ganglia?

Answer 42

- caudate nucleus - putamen - globus pallidus

Question 43

what comprises the sub-thalamic nuclei?

Answer 43

the thalamus itself which is composed of seven sub thalamic nuclei

Question 44

what does damage/disease of the basal ganglia action selection centres result in?

Answer 44

movement disorders

Question 45

what does parkinsons disease mainly affect?

Answer 45

substantia nigra

Question 46

what does huntingsons disease affect?

Answer 46

striatum

Question 47

describe parkinsons disease

Answer 47

- hypokinetic - decrease in refined movements - resting tremor (paralysis agitans) - poverty of movement - mask-like facial appearance - difficulty initiating movements - dopamine deficiency in aubstantia nigra

Question 48

describe huntingtons disease

Answer 48

- hyperkinetic - increased movements - excessive, uncontrolled movements - imbalance of neurotransmitters (decreased GABA) - some may have this through a genetic basic

Question 49

location of cerebellum

Answer 49

back of brain, behind brainstem, beneath occipital lobe

Question 50

what is the function of the cerebellum?

Answer 50

- important in co-ordinating movements - regulates actions of antagonistic muscle groups - important in maintaining balance (inputs from propioceptors) - acts to compare actual performance with what is intended

Question 51

describe muscle involvement in an action

Answer 51

- rare for only one set of muscles to be involved - action by one set of muscles is often accompanied by the actions of other muscles - these actions are coordinated to ensure posture/balance is maintained

Question 52

describe the maintenance of posture

Answer 52

- even standing still requires coordinated muscle action - activity of various muscles are adjusted as necessary - muscle contractions are controlled by inputs from variety of receptors - stretch reflexes are mediated by muscle spindles

Question 53

what are the actions which would occur if we lose balance?

Answer 53

correcting actions

Question 54

what are the methods in which motor outputs are refined?

Answer 54

- association cortex - subcortical areas