Voluntary Movement Flashcards
What are the three types of movements?
- Involuntary actions - reflexes
- Semi-automatic actions
- Voluntary actions
What are characteristics of semi-automatic actions?
‘Voluntary’; but you don’t have to think about them
* Often, they are repeated movement sequences
What are examples of semi-automatic actions?
chewing, walking, breathing
What is a basic structure of a neuron?
cell body (soma)
dendrites
axon
axon terminals
What are central pattern generators (CPG)?
collections of neurones that have rhymes outputs that will influence motor patterns of particular muscle groups
What can control CPGs?
higher control neurones
What are characteristics of voluntary actions?
- Self-initiated
- Purposeful - goal directed
- Learned
- Improved with practice
- Adaptable
Where does the motor cortex lie?
next to primary sensory cortex
anterior to central sulcus
What are the areas of spinal white matter?
dorsal funiculus
lateral funiculus
ventral funiculus
What is the descending pathway of voluntary movement of the face called?
corticobulbar pathway
What cranial nerves are located in the pons?
trigeminal, facial
What cranial nerves are located in the medulla?
vagus, hypoglossal
What is the descending pathway of voluntary movement of the body called?
corticospinal pathway
What is the main differences between the corticospinal and corticobulbar pathways?
corticospinal pathway descends further and crosses over to the opposite at the level of the medulla
What is the crossing over of axons called?
pyramidal decussation
What percentage of axons cross over at the level of the medulla and not below?
85%
What is the region in which axons cross over called?
lateral corticospinal tract
What is the region in which 15% of axons that cross over at effector spinal regions reside in? (to mid thoracic spinal cord only)
anterior corticospinal tract
Where do pathways controlling faraway muscles originate?
opposite side of the brain
What can damage (stroke, lesion) to the upper motors cause?
no voluntary movement however reflex pathway still intact as it does not interact with upper neurone
What can damage (peripheral nerve injury) to the lower motors cause?
no movement at all
What regions of the brain can the additional descending projections arise from?
basal ganglia, cerebellum, brainstem
What actions can these additional regions support?
- Serve to co-ordinate movements
- Help maintain posture / balance
- Help integrate actions of several muscles
What are the three action selection centres of the basal ganglia?
corpus striatum
sub-thalamic nuclei
substantia nigra
What is the corpus stratum composed of?
caudate nucleus
putamen
globus pallidus
What is Parkinson’s disease caused by?
damage to substantia nigra
What is Huntington’s disease cause by?
damage to corpus striatum
What is hypokinetic?
lack of movement
What are characteristics of Parkinson’s disease?
- Hypokinetic disorder
Resting tremor (paralysis agitans) - Lack of movement
- ‘Mask-like’ face
- Difficulty initiating movements due to dopamine deficiency in substantia nigra
What is hyperkinetic?
increase in movements
What are characteristics of Huntington’s disease?
- Hyperkinetic disorder
- Excessive, uncontrolled movements
- Imbalance of neurotransmitters – Decreased levels of GABA
- Some may have a genetic basis
affects the corpus straitum
What are roles of the cerebellum?
- Important in 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
What will swaying forward slightly do to posture?
The stretch reflex evoked will pull the subject back to the vertical position
What is upright posture maintained by?
smaller correcting actions
