Examples of motor unit in the following topics:
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- The motor unit is the functional unit of muscle contraction and includes the motor nerve fiber and the muscle fibers it innervates.
- A motor unit consists of the motor neuron
and the grouping of muscle fibers innervated by the neuron.
- Precision is inversely
proportional to the size of the motor unit.
- Thus, small motor units can
exercise greater precision of movement compared to larger motor units.
- Groups of motor units are innervated to
coordinate contraction of a whole muscle and generate appropriate movement; all
of the motor units within a muscle are considered a motor pool.
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- A motor unit is comprised of a single alpha-motor neuron and all the muscle fibers it innervates.
- When a motor unit is activated, all of its fibers contract.
- All of the motor units that subserve a single muscle are considered a motor unit pool.
- Motor unit recruitment is a measure of how many motor neurons are activated in a particular muscle.
- These small motor units may contain only 10 fibers per motor unit.
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- Within a muscle summation can occur across motor units to recruit more muscle fibers, and also within motor units by increasing the frequency of contraction.
- When a weak signal is sent by the central nervous system to contract a muscle, the smaller motor units, being more excitable than the larger ones, are stimulated first.
- As the strength of the signal increases, more (and larger) motor units are excited.
- The largest motor units have as much as 50 times the contractile strength as the smaller ones; thus, as more and larger motor units are activated, the force of muscle contraction becomes progressively stronger.
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- A full factorial experiment is an experiment whose design consists of two or more factors, each with discrete possible values (or levels), and whose experimental units take on all possible combinations of these levels across all such factors.
- Suppose an engineer wishes to study the total power used by each of two different motors, $A$ and $B$, running at each of two different speeds, 2000 or 3000 RPM.
- The factorial experiment would consist of four experimental units: motor $A$ at 2000 RPM, motor $B$ at 2000 RPM, motor $A$ at 3000 RPM, and motor $B$ at 3000 RPM.
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- The motor areas of the brain are located in both hemispheres of the cortex.
- The right half of the motor area controls the left side of the body, and the left half of the motor area controls the right side of the body.
- Premotor cortex: Located anterior
to the primary motor cortex and responsible for some aspects of motor
control.
- Various experiments
examining the motor cortex map showed that each point in motor cortex
influences a range of muscles and joints, indicating significant overlapping in
the map.
- $$Topography of the human motor cortex, including the premotor cortex, SMA, primary motor cortex, primary somatosensory cortex, and posterior parietal cortex.
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- The golden rule in reducing the cost of running a motor is to ensure that it's the right-size motor for the job.
- Many businesses run motors that are too big for the task under the assumption that the additional horsepower may be needed in the future.
- Over-sized (and therefore under-loaded) motors waste energy and cost more to run.
- In many cases running two smaller energy-efficient motors can actually cost less than operating one over-sized motor.
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- Motors are ubiquitous.
- In fact, motors use up so much electricity that the amount they consume over their lifetime always costs more than the price of the motors themselves (some motors actually consume, in electricity costs, the amount of their purchase price every few weeks).
- Compare these figures to an older model 100 horsepower motor running continuously at full load (as many motors are designed to do), which can cost $70,000 a year to operate – or an older 20 horsepower motor, which can consume up to $14,000 worth of electricity annually.
- That's about six times the purchase price of the motor.
- Diesel or gasoline motors can be even more costly.
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- The motor pathway, also called the pyramidal tract or the corticospinal tract, serves as the motor pathway for upper motor neuronal signals coming from the cerebral cortex and from primitive brainstem motor nuclei.
- The motor impulses originate in the giant pyramidal cells (Betz cells) of the motor area, i.e., the precentral gyrus of the cerebral cortex.
- These are the upper motor neurons of the corticospinal tract.
- Peripheral motor nerves carry the motor impulses from the anterior horn to the voluntary muscles.
- The midbrain nuclei include four motor tracts that send upper motor neuronal axons down the spinal cord to lower motor neurons.
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- The basal ganglia (or basal nuclei, ) are a group of nuclei of varied origin in the brains of vertebrates that act as a cohesive functional unit.
- The basal ganglia are associated with a variety of functions, including voluntary motor control, procedural learning relating to routine behaviors or "habits" such as bruxism, eye movements, and cognitive, emotional functions.
- Experimental studies show that the basal ganglia exert an inhibitory influence on a number of motor systems, and that a release of this inhibition permits a motor system to become active.
- The pallidum receives its most important input from the striatum (either directly or indirectly), and sends inhibitory output to a number of motor-related areas, including the part of the thalamus that projects to the motor-related areas of the cortex.
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- In physics, power is the rate of doing work—the amount of energy consumed per unit time.
- It is the amount of energy consumed per unit time.
- The unit of power is the joule per second (J/s), known as the watt (in honor of James Watt, the eighteenth-century developer of the steam engine).
- For example, the rate at which a lightbulb transforms electrical energy into heat and light is measured in watts (W)—the more wattage, the more power, or equivalently the more electrical energy is used per unit time .
- The output power of an electric motor is the product of the torque the motor generates and the angular velocity of its output shaft.