Movement And Motor Control

Question 1

Which types of muscles increase an angle ie straighten

Answer 1

Extensors

Question 2

Which muscles decrease an angle ie bend

Answer 2

Flexors

Question 3

What are muscle which belong to same group - pull in same way ie extensors

Answer 3

Synergists

Question 4

What are flexors and extensors

Answer 4

Antagonists

Question 5

What has to happen to extensors for flexion to occur

Answer 5

Relax and flexors contract

Question 6

Which neurones allow contraction of muscles

Answer 6

Alpha motor neurones

Question 7

Where are alpha neurones from

Answer 7

Ventral horn in spinal cord

Question 8

What is a motor unit

Answer 8

Alpha motor neurone attached to a muscle fibre

Question 9

What are motor units called which have 1 alpha motor neurone impacting more muscle fibres

Answer 9

Large motor units

Question 10

Where are large motor units located compared to small

Answer 10

Legs and arms for large force of contraction

Fingers have small motor units (no branching of alpha neurones)

Question 11

Which muscle contraction movement has smallest AP firing frequency

Answer 11

Twitches

Question 12

What is the muscle contraction which doesn’t allow relaxation between ap

Answer 12

Summation (strength increases)

Question 13

What is the difference between unfused tetanus and fused tetanus

Answer 13

Unfused relax small amounts between AP (also smaller AP)

Fused don’t relax and large Hz

Question 14

Which muscle contraction would be used to hold a weight

Answer 14

Fused tetanus

Question 15

Which 3 things control alpha motorneurones and therefore contraction

Answer 15

Upper motor neurone (in cerebral cortex and brain stem)

Interneurones (excitatory and inhibitory in the spinal cord)

Receptors in muscles

Question 16

Which 2 receptors are located in muscle

Answer 16

Muscle spindles

Golgi tendon organs

Question 17

What are fibres in the muscle called which contract to move joint

Answer 17

Extra fusal

Question 18

What fibres make up muscle spindle receptor

Answer 18

Intra fusal fibres (with myofibrils for contraction)

Question 19

Which nerve fibre / sensory neurone detects stretch in the muscle in the muscle spindle

Answer 19

1a afferent fibre

Question 20

Where does the 1a afferent output to when muscle has stretched and what happens

Answer 20

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)

Question 21

What happens to intrafusal muscles when alpha motor neurone increases input

Answer 21

Contract and shorten (usually on ends of muscle spindles)

Question 22

Which motor neurones are attached to the ends of muscle spindles

Answer 22

Gamma motor neurones

Question 23

What happens if gamma motor neurone also fires with alpha motor neurone

Answer 23

Gamma firing causes stretching in middle of the muscle spindle so A1 afferent doesn’t stop sending impulses to cns

Question 24

Why would gamma motor neurone firing stopping A1 inhibition be good

Answer 24

If more force or contraction is needed

Question 25

Are proprioceptors located in the muscle spindle and Golgi tendon organs

Answer 25

Yes

Question 26

What is alpha and gamma firing called

Answer 26

Alpha gamma coactivation

Question 27

Is voluntary movement always conscious

Answer 27

No, unconscious memory

Question 28

What is the difference between voluntary and rhythmic movement

Answer 28

Rhythmic follows an automatic pattern eg walking Voluntary can be new things learned eg playing piano

Question 29

What needs to be in a reflex arc

Answer 29

1 sensory neurone and a motor neurone

Question 30

Where do reflexes originate

Answer 30

Brain stem and spinal cord

Question 31

Do reflexes have to be mono synaptic

Answer 31

No sometimes more neurones so polysynaptic

Question 32

How is the stretch reflex via 1a fibre a mono synaptic reflex

Answer 32

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

Question 33

Which reflex protects against excessive load stretch of muscles

Answer 33

Golgi tendon reflex

Question 34

What happens in Golgi tendon reflex which causes load to drop

Answer 34

Increased stretch signals causes activation of inhibitory interneurones in spinal cord These block firing down alpha neurones Muscle contraction stops

Question 35

Which muscles are stretched when someone hits knee tendon

Answer 35

Quadriceps

Question 36

What happens when A1 afferent fibre detects stretch in quadriceps in the knee tendon (causes extension)

Answer 36

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

Question 37

What receptor is responsible for hopping due to pain in foot

Answer 37

Nociceptors

Question 38

What must happen to bend leg away from pain

Answer 38

Contraction of flexor muscles via the alpha motor neurone and extensor muscles in that leg relax via inhibitory interneurones

Question 39

What must happen in leg which isn’t hurt to cause balance

Answer 39

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

Question 40

Which pathway needs to be stimulated to cause change in gravity of body to hop in reflex

Answer 40

Ascending pathway to brain

Question 41

What things make up the cerebral cortex

Answer 41

Sma Pma Motor cortex M1 Somatosensory cortex (sulcus and post central gyrus)

Question 42

What do sma and pma do

Answer 42

Plan movements

Question 43

Where does info for planning from sma and pma go

Answer 43

M1 motor cortex (where upper motor neurones are) down to the alpha neurone in ventral horn

Question 44

What is cerebellum for

Answer 44

Motor learning eg new movements like playing piano Also fine tuned movements

Question 45

What does the brain stem affect

Answer 45

Posture

Question 46

Where does movement feedback to

Answer 46

Spinal cord (spinal reflex)