Voluntary Movement Flashcards Preview

Nerves 1 > Voluntary Movement > Flashcards

Flashcards in Voluntary Movement Deck (32)
Loading flashcards...
1

Describe voluntary actions

Self-initiated
Purposeful - goal directed
Learned
Improved with practice
Adaptable

2

What are semi-automatic actions

Voluntary - but you don’t have to think about them
Often they are repeated movement sequences

3

Give examples of semi-automatic actions

Walking, breathing, chewing

4

What are CPGs

Central pattern generators
Initiate and maintain a specific action
May be synchronised eg - swinging arms and legs

5

Why are feedback loops important in CGPs

Constant feedback of info ensures that the reaction we have to our environment is appropriate

6

Describe the corticobulbar pathway

Arises from the primary motor cortex
Fibres converge and pass through the internal capsule to the brain stem
The neurons terminate on the motor nucleu of the cranial nerves where they synapse with lower motor neurons which carry the motor signals to the muscles of the face\

7

What is an important feature of the corticobulbar pathway

Often axons bifurcate meaning it can recruit muscles on both sides of the body allowing synchronised muscle contraction

8

Describe the corticospinal pathway

Originate in the motor cortex and axons project right through the brainstem to the pyramids in the medulla oblongata
Here the axons split, 85% cross over to the opposite side and project down the spinal cord to innervates their appropriate lower motor groups

9

What is the lateral corticospinal pathway

The 85% of the axons that cross over to the other side of the body

10

What is the anterior corticospinal pathway

The 15% of the axons which do not cross over to the other side of the body

11

What happens if a descending pathway is damaged

Damage (lesions) to pathway impairs their normal functions

12

What is a palsy

Paralysis to motor pathways caused by lesions

13

What are some causes of paralysis in lower motor neurons

Damage to LMN
Nerve injury
Viral infection (polio)

14

Describe paralysis in upper motor neurons

Damage in corticospinal and corticobulbar tracts
Damage to UMN
CNS injury (stroke)

15

What are some results of paralysis in lower motor neurons

No reflexes
No voluntary movement
Muscle atrophy

16

What are some results of paralysis in upper motor neurons

No voluntary movement
Reflexes present but exaggerated

17

What are additional descending motor projections

Arise from various areas of the cerebrum and brainstem
Basal ganglia, cerebellum and brainstem

18

What is the function of additional descending motor projections

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

19

What is the basal ganglia

Comprised of several interconnected sub-cortica nuclei
Link to cerebral cortex via feedback loops
Influence/regulate output from the motor cortex
Act to initiate actions and to switch from one action to another

20

What makes up the basal ganglia

Body of caudate nucleus
Putamen
Globes Pallidus
Thalamus
Substantial Nigra
Corpus callosum

21

What is the corpus callosum

Allows the two sides of the Brian to communicate

22

What are the action selection centres

Corpus striatum
Sub-thalamus nuclei
Substantial nigra

23

What makes up the corpus striatum

Caudate nucleus
Putamen
Globes pallidus

24

What does damage/disease to the substantial nigra result in

Parkinson’s disease

25

What does damage/disease to the corpus striatum result in

Huntington’s disease

26

Give examples of some basal ganglia disorders

Parkinson’s disease
Huntington’s disease (Chorea)

27

What do patients with Parkinson’s disease usually present with

Hypokinetic disorder so decreased movements
Resting tremor
Poverty of movements
Mask-like face
Difficulty initiating movements
Domapine deficiency in substantial nigra

28

What do patients with Huntington’s disease usually present with

Hyperkinetic disorder so increased movements
Excessive, uncontrolled movements
Imbalance of neurotransmitter
Decreased levels of GABA

29

What are the functions of the cerebellum

Co-ordinating movements
Regulates actions of antagonistic muscle groups
Important in maintaining balance - receives inputs from proprioceptors
Acts to compare actual performance with what is intended

30

Describe cerebellum disorders

Characterised by loss of co-ordination
Unsteady gait (ataxia)
Imprecise actions
Inability to co-ordinate altering contractions of antagonistic muscles
Intention tremor (resting tremor in Parkinson’s)

31

Why are actions usually co-iordinated

To ensure that posture/balance is maintained

32

Describe how posture is maintained

Forward sway stretches muscles in the back of the leg
Upright posture is maintained by a series of smaller correcting actions
These help keep the position of the head inline with gravity