Movement And Motor Control Flashcards
Which types of muscles increase an angle ie straighten
Extensors
Which muscles decrease an angle ie bend
Flexors
What are muscle which belong to same group - pull in same way ie extensors
Synergists
What are flexors and extensors
Antagonists
What has to happen to extensors for flexion to occur
Relax and flexors contract
Which neurones allow contraction of muscles
Alpha motor neurones
Where are alpha neurones from
Ventral horn in spinal cord
What is a motor unit
Alpha motor neurone attached to a muscle fibre
What are motor units called which have 1 alpha motor neurone impacting more muscle fibres
Large motor units
Where are large motor units located compared to small
Legs and arms for large force of contraction
Fingers have small motor units (no branching of alpha neurones)
Which muscle contraction movement has smallest AP firing frequency
Twitches
What is the muscle contraction which doesn’t allow relaxation between ap
Summation (strength increases)
What is the difference between unfused tetanus and fused tetanus
Unfused relax small amounts between AP (also smaller AP)
Fused don’t relax and large Hz
Which muscle contraction would be used to hold a weight
Fused tetanus
Which 3 things control alpha motorneurones and therefore contraction
Upper motor neurone (in cerebral cortex and brain stem)
Interneurones (excitatory and inhibitory in the spinal cord)
Receptors in muscles
Which 2 receptors are located in muscle
Muscle spindles
Golgi tendon organs
What are fibres in the muscle called which contract to move joint
Extra fusal
What fibres make up muscle spindle receptor
Intra fusal fibres (with myofibrils for contraction)
Which nerve fibre / sensory neurone detects stretch in the muscle in the muscle spindle
1a afferent fibre
Where does the 1a afferent output to when muscle has stretched and what happens
Cns
Cns allows increased output of alpha motorneurones eg via upper motorneurones or interneurones excitatory
Muscle can then contract unloading the spindle (stopping A1 fibre firing)
What happens to intrafusal muscles when alpha motor neurone increases input
Contract and shorten (usually on ends of muscle spindles)
Which motor neurones are attached to the ends of muscle spindles
Gamma motor neurones
What happens if gamma motor neurone also fires with alpha motor neurone
Gamma firing causes stretching in middle of the muscle spindle so A1 afferent doesn’t stop sending impulses to cns
Why would gamma motor neurone firing stopping A1 inhibition be good
If more force or contraction is needed
Are proprioceptors located in the muscle spindle and Golgi tendon organs
Yes
What is alpha and gamma firing called
Alpha gamma coactivation
Is voluntary movement always conscious
No, unconscious memory
What is the difference between voluntary and rhythmic movement
Rhythmic follows an automatic pattern eg walking
Voluntary can be new things learned eg playing piano
What needs to be in a reflex arc
1 sensory neurone and a motor neurone
Where do reflexes originate
Brain stem and spinal cord
Do reflexes have to be mono synaptic
No sometimes more neurones so polysynaptic
How is the stretch reflex via 1a fibre a mono synaptic reflex
Stretch occurs eg from weights and 1a from muscle spindle sends impulse to spinal cord which then synapses with the alpha neurone causing contraction of intrafusal muscles
Which reflex protects against excessive load stretch of muscles
Golgi tendon reflex
What happens in Golgi tendon reflex which causes load to drop
Increased stretch signals causes activation of inhibitory interneurones in spinal cord
These block firing down alpha neurones
Muscle contraction stops
Which muscles are stretched when someone hits knee tendon
Quadriceps
What happens when A1 afferent fibre detects stretch in quadriceps in the knee tendon (causes extension)
Alpha motor neurone in efferent pathway 1 stimulated contraction of quadriceps (extensors)
Efferent pathway 2 alpha motor neurone is inhibited via inhibitory interneurones - causes harmstring to relax (flexor)
= leg extends forward
What receptor is responsible for hopping due to pain in foot
Nociceptors
What must happen to bend leg away from pain
Contraction of flexor muscles via the alpha motor neurone and extensor muscles in that leg relax via inhibitory interneurones
What must happen in leg which isn’t hurt to cause balance
Alpha motor neurone stimulation via excitatory interneurones causing contraction of extensors to straighten leg
Flexors are relaxed due to inhibitory interneurones stopping alpha motor neurone
Which pathway needs to be stimulated to cause change in gravity of body to hop in reflex
Ascending pathway to brain
What things make up the cerebral cortex
Sma
Pma
Motor cortex M1
Somatosensory cortex (sulcus and post central gyrus)
What do sma and pma do
Plan movements
Where does info for planning from sma and pma go
M1 motor cortex (where upper motor neurones are) down to the alpha neurone in ventral horn
What is cerebellum for
Motor learning eg new movements like playing piano
Also fine tuned movements
What does the brain stem affect
Posture
Where does movement feedback to
Spinal cord (spinal reflex)
