Motor Control Systems Flashcards
Reflex
A simple, highly stereotyped, and unlearned response to a particular stimulus.
Monosynaptic
Motor plan
A plan for action in n.s. (Ex crawling)
Closed-loop control mechanisms
Maximize accuracy. Provides flow of info from whatever is being controlled to the device that controls it.
Open-loop control mechanism
Maximizes speed. Feedback from the output of the system is not provided to input control. Makes ballistic movements.
Tendon
Tissue that connects muscles to bones
Antagonist
A muscle that counteracts the effect of another muscle
Synergist
A muscle that acts together with another muscle.
Flexion
Pull towards body
Extension
Pull away from body
Primary motor cortex (M1)
In most posterior part of frontal cortex.
Nonprimary motor cortex
Supplementary- lateral part of frontal lobe
Premotor cortex- medial part of frontal lobe
Fast-twitch muscle fibers
Act quickly and fatigue quickly.
Slow-Twitch muscle fibers
Slower to respond but have endurance
Neuromuscular junction(NMJ)
The point where the nerve transmits ya message to the muscle fiber
Innervation ratio
The ratio expressing the number of muscle fibers innervated by a single motor axon.
Final common pathway
Consists of all motoneurons in body. Receive and integrate all motor signals from the brain and then direct movement accordingly.
Proprioception
Body sense. Info about the position and movement of body sent to brain.
Muscle spindle
A muscle receptor that lies parallel to a muscle and sends impulses to the cns when the muscle is stretched.
Intrafusal fiber
One of the small muscle fibers that lie within each muscle spindle.
Gamma motoneurons control
Extrafusal fiber
One of the ordinary muscle fibers that lie outside the spindles and provide most of the force for muscle contraction.
Controlled by alpha motoneurons
Primary sensory ending
Aka anulospiral ending.
The axon that transmits info from the central portion of a muscle spindle
Secondary sensory ending
Aka flower spray ending.
The axon that transmits info from ends of a muscle spindle
Golgi tendon organ
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.
Pyramidal system
Brain, to medulla, to spinal cord, to muscle.
Includes M1, and nonprimary motor cortex. Movements represented. Learning occurs here.
Supplementary motor area (SMA)
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
Extrapyramidal system
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
Reticulospinal tract
One pathway of extrapyramidal system. Starts at reticular formation. Descend to spinal cord
Rubrospinal tract
Starts in midbrain’s red nuc. Sends axons down spinal cord
Muscular dystrophy
Dystrophin protein mutation. Gene on X chrom.
Myasthenia gravis
Autoimmune disorder. Attacks ACh neurons, lose input to muscles, they weaken.
Polio
Virus. Selectively affects motor neurons. Starts at periphery, works inward.
ALS
Gradually worsening paralysis. Created locked-in syndrome.
Parkinson’s disease
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.
Parkinson’s treatment
L-Dopa- can help release DA, decrease symptoms for a while. Stem cell research - they deteriorate. Deep brain electrical stimulation.
Huntington’s disease
Single gene disorder, repeated trinucleotide. Fatal. First affects emotional, then. Motor problems.
Cerebellar damage
No cerebellum is ok. If have one and damage =ataxia, decomp of movements, jerky movements, tracking deficits in eyes.
Apraxia
Impairment in ability to begin and execute skilled voluntary movements even though there is not muscle paralysis
Paresis
Partial paralysis
Spasticity
Markedly increased rigidity in response to forced movement or the limbs
