Nerve06/central nervous system/basics of the motor pathwayのソースを表示

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The motor (efferent) action potentials descend from the cerebral cortex to the skeletal muscles via two (upper and lower) (primary and secondary) motor neurons. }}

The cell body for the primary (upper) motor neuron is in the precentral gyrus of the frontal lobe of the cerebral cortex.

The descending fibers of the primary motor neurons pass through the internal capsule, but not the thalamus.

The primary motor neuron fibers cross the right-left midline.

The primary motor neuron forms a synapse with the secondary motor neuron in the anterior horn of the spinal cord.

The secondary motor neuron fibers leave the spinal cord from the anterior root and innervate the skeletal muscle.


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//LEVEL:4
//RAND
The cell body of the primary (upper) motor neuron is located in the {~anterior horn~posterior horn~posterior root ganglion~thalamus~=precentral gyrus~postcentral gyrus~internal capsule}.





//LEVEL:4
//RAND
The cell body of the secondary (lower) motor neuron is located in the {=anterior horn~posterior horn~posterior root ganglion~thalamus~precentral gyrus~postcentral gyrus~internal capsule}.





//LEVEL:4
//NO-RAND

The {=primary (upper)~secondary (lower)} cross the right-left midline.






//LEVEL:4
//RAND

The fiber of the secondary (lower) motor neuron, after leaving the spinal cord, {=directly reaches~change neurons and then reach} the skeletal muscles. 







//LEVEL:2
//RAND
The motor descending pathway {=does~does not} pass through the internal capsule.





//LEVEL:3
//RAND
The motor descending pathway {~does~=does not} pass through the thalamus.





//LEVEL:3
//RAND

The {~afferent~=efferent} action potential for moving the RIGHT foot is generated in the {~right~=left} {~postcentral gyrus~=precentral gyrus}, and then passes through the  {~right~=left} internal capsule, {=right~left} side {=anterior~posterior} horn, {=right~left} side {=anterior~posterior} root, and reaches the skeletal muscle.





//LEVEL:3
//RAND
The {~afferent~=efferent} action potential for moving the LEFT foot is generated in the {=right~left} {~postcentral gyrus~=precentral gyrus}, and then passes through the  {=right~left} internal capsule, {~right~=left} side {=anterior~posterior} horn, {~right~=left} side {=anterior~posterior} root, and reaches the skeletal muscle.

</GIFT>