Motor Pathways Flashcards
Muscles work in what sort of pairs?
Antagonistic pairs
What are the names of the two enlargements on the spinal cord, and what do they do?
The cervical and lumbar enlargements are for the many nerves ennervating the arms and legs.
What is the neuromuscular junction?
A specialised synapse that transfers electrical signals from the central nervous system to the muscles.
What type of receptors are tightly packed in post-synaptic membranes?
Acetylcholine receptors.
What type of movements are controlled from the spinal cord? What type of movements are these?
Spinal reflexes and locomotion. Automatic, rhythmic movements.
What is the function of the cerebellum? What happens if it is damaged?
It refines movements, generates smooth, co-ordinated sequences of muscle interactions and is involved in learning new sequences of movements. Damage to the cerebellum results in poorly co-ordinated, robotic movements and loss of balance.
Which nerves run from the spinal cord to the muscles?
Motors nerves.
Where are purposeful, skilled movements initiated? Which other parts of the brain supplement this?
Purposeful and skilled movements are initiated in the motor cortex, supplemented by the basal ganglia and cerebellum.
Automatic movement involves activity in the…?
…brain and spinal cord.
Where in the brain is the primary motor cortex found?
In area 4 / M1, just forward of the central sulcus.
Where in the brain is the somatosensory cortex found?
S1, just behind the central sulcus.
The supplementary motor area and pre-motor area are where in the brain?
Area 6, in front of the motor cortex.
Specific areas of M1 (motor cortex) innervate specific body parts. The size of the area of M1 is relative to…?
…the level of control an area requires, for example relatively large regions are dedicated to the lips, face and hands.
What happens if the motor cortex is damaged?
Precision of movement is affected.
Which area of the brain codes for force AND direction of movement?
Motor cortex (M1).
Name the output of the human motor system that controls skille movements.
Corticospinal tract.
Which areas of the brain work together to direct voluntary, skilled movements?
M1, SMA/PMA and the somatosensory areas.
What is meant by clonic movement?
Rhythmic movement.
True or false? Sensory areas are unable to cause movements to happen.
False. Sensory areas can cause movements to happen but this takes a LOT more effort.
Describe the way that fine motor (fractionated) movements are controlled in primates.
Direct monosynaptic connections from the motor cortex to the spinal nerves.
What do the corticospinal motor neurones control in single synapses - but only in primates?
The hand and forearm.
Where is the laterocorticospinal tract?
The laterocorticospinal tract forms part of the internal capsule, cerebral peduncles and pyramids.
They are two tracts of single synapse motor neurone connections down the front of the brain stem.
Can complex, co-ordinated movements be stimulated by single-point stimulation?
No. They must come from the SMA.
Where do complex, co-ordinated movements HAVE to be stimulated from?
What are the two pathways that it can follow?
The SMA.
SMA - M1 - Brainstem
OR
SMA - lateral corticospinal tract.
Damage to which part of the brain causes Parkinson’s disease
Basal ganglia.
What does the basal ganglia do?
It is thought that it modulates voluntary movements.
Where do signals passing through the basal ganglia come from? Where do they go next?
Signals from the motor cortex pass through the basal ganglia before looping back through the motor cortex before leaving the brain.
What is the role of the cerebellum?
Refining movements and generating smooth, coordinated muscular actions.
It is also associated with learning new sequences of movements.
Damage to which part of the brain causes robotic, uncoordinated movements and loss of balance?
Cerebellum.
Is the cerebellum large or small in humans?
Very large.
Name the part of the brain:
‘an interconnected loop of neurones which is constantly active, refining information from the motor cortex’.
Cerebellum.
Name the part of the CNS:
‘involved in controlling innate behaviours, e.g. posture, grooming, feeding etc. Controls rhythmic motion and the speed of locomotion in quadrapeds.’
Brain stem.
The spinal cord is NOT just a conduit - it generates …………… ……………. for locomotion.
Rhythmic patterns.
