Motor Flashcards
Learnt threat =
cortex and limbic system
Loom =
sensorimotor midbrain
Pain=
SPinal cord
How do muscles contract
The Myosin cross bridge
Calcium
Actin
AtP
The motor unit is
a single alpha + all the muscle fibres it innervates
The motor pool is
All the lower motor neurons which innervate a single muscle
Dorsal route
Back.
Sensory, input ascending. unipolar, afferent. CNS spinal cord.
VEntral route
Front
Motor, descending. Multipolar, efferent. Muscles.
Proprioception is
Sensing in muscles
What detects tension in a muscle
Golgi tendons- in the tendon, signals to spinal cord to make adjustments.
What detects strecth in a muscle
Muscle spindles- wrap around the intrafusal, innervated by gamma (seperately to detect stretch)
Control of muscle force?
- Level of control - little force= muscle fibres which recruit fewer fibres.
- Strength
The size principle- recruits smallest first.
How many layers or the motor cortex
6
Where do the projections originate
motor cortex pyramidal cells
where are the cell bodies located
grey matter of the cortex
Cortical projections innervate…
contralateral motor units.
The basal ganglia
Group of nuclei deep within the cerebral hemispheres.
motor control
Receives excitatory input from cortex- GLU
Outputs via thalamus
Output is inhibitory - GABA
The selection problem. Centralised selection.
Recurrent reciprocal inhibition.
- PArkinsons disease
- Huntingtons disease
- Tourettes
- TArdire Dyskinesia
- Hemiballismus
The cerebellum
Conains half of the CNS neurons
INtention tremor, Dysarthia, jerky unco-ordinated.
Computes motor errors.
Excitatory output.
The dorsolateral corticospinal tract?
Betz cells- Extremely large pyramidal cells of the motor cortex
Synapse on the medullary pyramid- contrlaterally to the distal muscles of the hands.
The dorsolateral corticorubrospinal tract
synapses on the red nucleus. - distal muscles of arms and legs.
contralateral.
Ventromedial corticospinal tract
Ipsilaterally. Motor.
Proximal.
Ventromedial cortico- brainstem spinal tract
ipsilaterally
- tectum
- the vestibular nucleus
- the reticular formation
- the motor nucleus of the cranial nerves which control the muscles
where are betz cells found?
they are extremely large pyramidal cells of the primary motor cortex.
what is recurrent collateral inhibition
distributes the work between different motor neurons of the muscles motor pool
what cells are recurrent collateral inhibition mediated by
renshaw cells
