Movement Flashcards
reflex movements
rapid, reproducible, automatic motor response to external stimulus. neural circuit involves peripheral nerves and spinal cord. do not require involvement of higher brain centres
voluntary movements
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.
stretch reflex
step 1
stimulation of a receptor - causes the muscle to stretch a little
stretch reflex
step 2
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
stretch reflex
step 3
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
stretch reflex
step 5
response of a peripheral effector - AP on the skeletal muscle fibre will cause the muscle fibre to contract creating the response
withdrawal reflex
step 1
stimulation of a receptor
withdrawal reflex
step 2
activation of a sensory neuron - enters the CNS along the dorsal root
withdrawal reflex
step 3
information processing in the CNS - information goes to higher centres in the brain, synapse on an inter neuron
withdrawal reflex
step 4
activation of a motor neuron - previous synapse activates the motor neuron
withdrawal reflex
step 5
response of a peripheral effector - motor neuron activates the muscle fibres
voluntary movement
initiated in the …
brain
voluntary movement
1
sensory information coming from … and … and … enter the … through the … division of … and then into the … for … processing
muscles, skin, other receptors, CNS, afferent, PNS, brain, information
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.
brain, limbs, where, what
voluntary movement
3
the … produces a complex …
brain, output
voluntary movements
4
by activating the … … division of the … this activates the … … to execute the movement
motor efferent, PNS, skeletal muscle
voluntary movements
5
much of the … is involved in the … and … of movements
brain, planning, performing
1˚ motor cortex
area distribution
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)
cerebellum functions (5)
- 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
voluntary movements
step 1
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
voluntary movements
step 2
desire to initiate a movement typically arises in frontal cortex
voluntary movements
step 3
various directly motor-related regions of brain are activated
voluntary movements
step 4
descending pathways (corticospinal tracts to brainstem and spinal cord) are activated
voluntary movements
step 5
corticospinal tracts cross in the medulla, so left brain controls right body
voluntary movements
step 6
corticospinal tract neurons terminate on motoneurons & interneurons
voluntary movements
step 7
axons of spinal cord motoneurons extend to periphery, activate skeletal muscles
voluntary movements
step 8
sensory info is fed back into the system, and the activity of motor neurons is modulated to modify and control the movement
voluntary movements
step 8
sensory info is fed back into the system, and the activity of motor neurons is modulated to modify and control the movement
voluntary movement
brain functions
frontal lobe
decision to make movement based on intentions, memories and experiences, risk, personality, emotion and environment
voluntary movement
brain functions
premotor cortex
plans what the movement will be, activating neurons that spark muscles
voluntary movement
brain functions
basal nuclei
adjusts patterns of movement in two ways
- they alter the sensitivity of the pyramidal cells to adjust the output along the corticospinal tract
- they change the excitatory or inhibitory output of the medial and lateral pathways
voluntary movement
brain functions
cerebellum
monitors balance and equilibrium and adjusts upper motor neuron activity
