Movement

Question 1

reflex movements

Answer 1

rapid, reproducible, automatic motor response to external stimulus. neural circuit involves peripheral nerves and spinal cord. do not require involvement of higher brain centres

Question 2

voluntary movements

Answer 2

wide variety of movements of varying speed, duration, and complexity. involves complex patterns of sensory and motor processing. initiated on demand (voluntarily) in brain, many brain centres involved in control.

Question 3

stretch reflex

step 1

Answer 3

stimulation of a receptor - causes the muscle to stretch a little

Question 4

stretch reflex

step 2

Answer 4

activation of a sensory neuron - in skeletal muscles there are stretch receptors which have mechanically gated ion channels in the nerves. this lengthens the muscle spindles in the muscle and generates a local potential in the nerve endings

Question 5

stretch reflex

step 3

Answer 5

information processing in the CNS - if the local potential is big enough, an AP will be fired in the sensory fibre and is conducted along the sensory fibre (dorsal root pathway) into the spinal cord. synaptic transmission occurs

Question 6

stretch reflex

step 5

Answer 6

response of a peripheral effector - AP on the skeletal muscle fibre will cause the muscle fibre to contract creating the response

Question 7

withdrawal reflex

step 1

Answer 7

stimulation of a receptor

Question 8

withdrawal reflex

step 2

Answer 8

activation of a sensory neuron - enters the CNS along the dorsal root

Question 9

withdrawal reflex

step 3

Answer 9

information processing in the CNS - information goes to higher centres in the brain, synapse on an inter neuron

Question 10

withdrawal reflex

step 4

Answer 10

activation of a motor neuron - previous synapse activates the motor neuron

Question 11

withdrawal reflex

step 5

Answer 11

response of a peripheral effector - motor neuron activates the muscle fibres

Question 12

voluntary movement

initiated in the …

Answer 12

brain

Question 13

voluntary movement
1
sensory information coming from … and … and … enter the … through the … division of … and then into the … for … processing

Answer 13

muscles, skin, other receptors, CNS, afferent, PNS, brain, information

Question 14

voluntary movement
2
the … is constantly aware of where our … are at any time so when we make a … decision to execute a movement the activation can be informed by … the libs are and … they are doing.

Answer 14

brain, limbs, where, what

Question 15

voluntary movement
3
the … produces a complex …

Answer 15

brain, output

Question 16

voluntary movements
4
by activating the … … division of the … this activates the … … to execute the movement

Answer 16

motor efferent, PNS, skeletal muscle

Question 17

voluntary movements
5
much of the … is involved in the … and … of movements

Answer 17

brain, planning, performing

Question 18

1˚ motor cortex

area distribution

Answer 18

the largest areas of the motor cortex are occupied by neurons projecting to muscles capable of the finest and most complex movements (e.g. lips)

Question 19

cerebellum
functions (5)

Answer 19

• helps plan, execute, and learn motor programs
• integrates sensory info with planned events
• receives information from proprioceptive sensory neurons
• organises timing of muscle contractions, compares result of planned movement with actual result, modifies ongoing activity to make movements smooth and accurate and results in a good end point
• important for control of postural movements to retain balance and body position

Question 20

voluntary movements

step 1

Answer 20

sensory info about the environment and the state of the body is used to plan movements, neural commands are sent to muscles to generate forces to execute movements

Question 21

voluntary movements

step 2

Answer 21

desire to initiate a movement typically arises in frontal cortex

Question 22

voluntary movements

step 3

Answer 22

various directly motor-related regions of brain are activated

Question 23

voluntary movements

step 4

Answer 23

descending pathways (corticospinal tracts to brainstem and spinal cord) are activated

Question 24

voluntary movements

step 5

Answer 24

corticospinal tracts cross in the medulla, so left brain controls right body

Question 25

voluntary movements

step 6

Answer 25

corticospinal tract neurons terminate on motoneurons & interneurons

Question 26

voluntary movements

step 7

Answer 26

axons of spinal cord motoneurons extend to periphery, activate skeletal muscles

Question 27

voluntary movements

step 8

Answer 27

sensory info is fed back into the system, and the activity of motor neurons is modulated to modify and control the movement

Question 28

voluntary movements

step 8

Answer 28

sensory info is fed back into the system, and the activity of motor neurons is modulated to modify and control the movement

Question 29

voluntary movement
brain functions
frontal lobe

Answer 29

decision to make movement based on intentions, memories and experiences, risk, personality, emotion and environment

Question 30

voluntary movement
brain functions
premotor cortex

Answer 30

plans what the movement will be, activating neurons that spark muscles

Question 31

voluntary movement
brain functions
basal nuclei

Answer 31

adjusts patterns of movement in two ways

1. they alter the sensitivity of the pyramidal cells to adjust the output along the corticospinal tract
2. they change the excitatory or inhibitory output of the medial and lateral pathways

Question 32

voluntary movement
brain functions
cerebellum

Answer 32

monitors balance and equilibrium and adjusts upper motor neuron activity