Motor Control Systems

Question 1

Reflex

Answer 1

A simple, highly stereotyped, and unlearned response to a particular stimulus.
Monosynaptic

Question 2

Motor plan

Answer 2

A plan for action in n.s. (Ex crawling)

Question 3

Closed-loop control mechanisms

Answer 3

Maximize accuracy. Provides flow of info from whatever is being controlled to the device that controls it.

Question 4

Open-loop control mechanism

Answer 4

Maximizes speed. Feedback from the output of the system is not provided to input control. Makes ballistic movements.

Question 5

Tendon

Answer 5

Tissue that connects muscles to bones

Question 6

Antagonist

Answer 6

A muscle that counteracts the effect of another muscle

Question 7

Synergist

Answer 7

A muscle that acts together with another muscle.

Question 8

Flexion

Answer 8

Pull towards body

Question 9

Extension

Answer 9

Pull away from body

Question 10

Primary motor cortex (M1)

Answer 10

In most posterior part of frontal cortex.

Question 11

Nonprimary motor cortex

Answer 11

Supplementary- lateral part of frontal lobe

Premotor cortex- medial part of frontal lobe

Question 12

Fast-twitch muscle fibers

Answer 12

Act quickly and fatigue quickly.

Question 13

Slow-Twitch muscle fibers

Answer 13

Slower to respond but have endurance

Question 14

Neuromuscular junction(NMJ)

Answer 14

The point where the nerve transmits ya message to the muscle fiber

Question 15

Innervation ratio

Answer 15

The ratio expressing the number of muscle fibers innervated by a single motor axon.

Question 16

Final common pathway

Answer 16

Consists of all motoneurons in body. Receive and integrate all motor signals from the brain and then direct movement accordingly.

Question 17

Proprioception

Answer 17

Body sense. Info about the position and movement of body sent to brain.

Question 18

Muscle spindle

Answer 18

A muscle receptor that lies parallel to a muscle and sends impulses to the cns when the muscle is stretched.

Question 19

Intrafusal fiber

Answer 19

One of the small muscle fibers that lie within each muscle spindle.
Gamma motoneurons control

Question 20

Extrafusal fiber

Answer 20

One of the ordinary muscle fibers that lie outside the spindles and provide most of the force for muscle contraction.
Controlled by alpha motoneurons

Question 21

Primary sensory ending

Answer 21

Aka anulospiral ending.

The axon that transmits info from the central portion of a muscle spindle

Question 22

Secondary sensory ending

Answer 22

Aka flower spray ending.

The axon that transmits info from ends of a muscle spindle

Question 23

Golgi tendon organ

Answer 23

One of the receptors located in tendons that send impulses to cns reporting muscle tension. Sensitive to muscle tension, how much stress on muscle. Activate reflex to drop something if will cause damage.

Question 24

Pyramidal system

Answer 24

Brain, to medulla, to spinal cord, to muscle.

Includes M1, and nonprimary motor cortex. Movements represented. Learning occurs here.

Question 25

Supplementary motor area (SMA)

Answer 25

Rigoberto of nonprimary motor cortex that receives input from basal ganglia and modulates the activity of primary motor cortex.
Initiates movements, mental rehearsal of movements

Question 26

Extrapyramidal system

Answer 26

Doesn’t go thru pyramidal structures in medulla. Goes thru basal ganglia. Involved in initiation, amplitude and direction, habitual movements, addictions, OCD. Cerebellum- skilled movements, learned motor programs, classical conditioning

Question 27

Reticulospinal tract

Answer 27

One pathway of extrapyramidal system. Starts at reticular formation. Descend to spinal cord

Question 28

Rubrospinal tract

Answer 28

Starts in midbrain’s red nuc. Sends axons down spinal cord

Question 29

Muscular dystrophy

Answer 29

Dystrophin protein mutation. Gene on X chrom.

Question 30

Myasthenia gravis

Answer 30

Autoimmune disorder. Attacks ACh neurons, lose input to muscles, they weaken.

Question 31

Polio

Answer 31

Virus. Selectively affects motor neurons. Starts at periphery, works inward.

Question 32

ALS

Answer 32

Gradually worsening paralysis. Created locked-in syndrome.

Question 33

Parkinson’s disease

Answer 33

Loss of dopamine neurons. Affects pathways to basal ganglia. Causes tremors, unable to initiate movement, lack of facial expressions. Brain compensates for loss of DA at first, allows disease to progress a lot. Most environmental factors- not genetic.

Question 34

Parkinson’s treatment

Answer 34

L-Dopa- can help release DA, decrease symptoms for a while. Stem cell research - they deteriorate. Deep brain electrical stimulation.

Question 35

Huntington’s disease

Answer 35

Single gene disorder, repeated trinucleotide. Fatal. First affects emotional, then. Motor problems.

Question 36

Cerebellar damage

Answer 36

No cerebellum is ok. If have one and damage =ataxia, decomp of movements, jerky movements, tracking deficits in eyes.

Question 37

Apraxia

Answer 37

Impairment in ability to begin and execute skilled voluntary movements even though there is not muscle paralysis

Question 38

Paresis

Answer 38

Partial paralysis

Question 39

Spasticity

Answer 39

Markedly increased rigidity in response to forced movement or the limbs