physiology- motor system

inner

grey matter makes up the _______ (inner/outer) part of the spinal cord.

sensory

the dorsal horns of the grey matter of the spinal cord process ________ information

vental horns

to what part of the spinal cord does motor information from the CNS go?

ascending
(information coming from the body and going to the brain)

do the dorsal horns of the spinal cord contain ascending or descending tracts?

ventral horns

which horns of the spinal cord contain descending tracts (information going from the brain to the effector)?

lateral horns

where does exchange of visceral information occur within the spinal cord?

visceral information

what type of information is exchanged in the lateral horns of the spinal cord?

white

_________ matter is located on the outer part of the spinal cord

larger soma
longer and larger dendrites and axon
greater number of synaptic endings

how are motor neurons different from other neurons morphologically?

alpha neurons

which motor neurons innervate the extrafusal skeletal muscle fibers?

gamma neurons

which motor neurons innervate the intrafusal skeletal muscle fibers?

alpha motor neurons (innervate extrafusal muscle fibers)
gamma motor neurons (innervate intrafusal muscle fibers)

what 2 motor neurons innervate skeletal muscles?

in the ventral horns of the grey matter

where are motor neurons located in the spinal cord?

in all areas of grey matter

where are interneurons located in the spinal cord?

no, reflexes stay within the spinal cord.
sensory neurons bring info to the dorsal horns and synapse with interneurons, which synapse with motor neurons which carry out the needed reflex.
voluntary motor pathways reach the brain.

do all motor pathways reach the brain?

pyramidal system

which, the extrapyramidal system or pyramidal system is a direct pathway involved in voluntary and fine motor control?

pyramidal- voluntary control
extrapyramidal- regulating posture, muscle tone, involuntary reflexes, and coordination of movement, etc.

what is the difference between the pyramidal system and the extrapyramidal system?

corticonuclear tract

which tract of the pyramidal system controls voluntary facial movement?

voluntary movement of the body (-the face/head)

what does the corticospinal tract do?

voluntary; 3

the pyramidal system is _____ (voluntary/involuntary) and uses ____ neurons to connect the motor cortex to the skeletal muscles

motor cortex of the cerebral cortex

the UMN of the pyramidal tracts has its soma in the _________

yes the lateral corticospinal tract does, at the brain stem

do the pyramidal tracts decussate?

an interneuron (in the ventral horn of the spinal cord)

after the UMN of the pyramidal tracts reaches its destination in the spinal cord, it synapses with _______

interneuron; ventral horn; ventral root

the LMN of the pyramidal system receives its info from the ______ in the _____ of the spinal cord, and then exits the spinal cord through the ________

pyramidal pathways:
lateral corticospinal tract
anterior corticospinal tract

this represents which motor pathway?

subconsciously

is the extrapyramidal system controlling movement voluntarily or subconsciously?

1. reticulospinal tract
2. vestibulospinal tract
3. rubrospinal tract
4. tectospinal tract

what are the 4 important tracts within the extrapyramidal system?

medulla oblongata

the UMN from the lateral corticospinal system decussates at the _____

internal capsule of cerebrum
cerebral peduncle
basal pons
pyramids of medulla

in the brain, what structures does the UMN of the pyramidal tracts go through?

corticonuclear tract

which motor tract originates in the primary motor cortex, but does not reach the spinal cord?

pyramidal
(they are all facilitating voluntary movement)

the corticonuclear, anterior and lateral corticospinal tracts belong to the _____ system

2 pyramids

the axons of the UMN of the lateral and anterior corticospinal tract converge in the corona radiata of the medulla, forming the ________

lateral corticospinal tract

which pyramidal tract decussates?

no

does the anterior corticospinal tract decussate?

80; 20

_____% of conscious motor info goes through the lateral corticospinal tract, while _____% goes through the anterior corticospinal tract

reticular nuclei; nuclei of cranial nerves

most fibers of the corticonuclear tract end in __________ before reaching _______

no

do axons in the extrapyramidal system pass through the pyramids in the medulla?

brain stem

where is the origination of the extrapyramidal tracts?

primary motor cortex of the cerebrum; brain stem

pyramidal tracts originate in the __________, while extrapyramidal tracts originate in the _________

complete the function of the pyramidal system- when doing voluntary movements, it is necessary to maintain balance and posture, which is done by the extrapyramidal tracts

what is the function of the extrapyramidal tracts?

red nucleus in the midbrain

the origin of the rubrospinal tract is the _____

lateral vestibular nuclei in the medulla and pons

what is the origin of the vestibulospinal tract?

reticular formation in the pons

what is the origin of the reticulospinal tract?

in the superior culiculus in the midbrain

where does the tectospinal tract originate?

facilitation of flexor activity and inhibition of extensor activity (mostly in the front limbs)

what is the specific function of the rubrospinal tract?

rubrospinal tract

which tract facilitates flexion and inhibits extension ?

red nucleus; cerebral cortex and cerebellum

the soma of the UMN of the rubrospinal tract is in the _______, and it receives information from the __________

facilitation of muscle extension and inhibition of muscle flexion, mostly of the hind limbs
and keeps the head straight

what is the function of the vestibulospinal tract?

vestibulospinal; vestibular nuclei

the ________ tract inhibits flexion and facilitates extension, as well as keeps the head straight, and the body of its UMN is in the _______

control proximal muscles (subconsciously- posture, balance, etc) to keep up standing straight

what is the function of the reticulospinal tract?

reticulospinal tract

which tract subconsciously keeps us standing straight by controlling the proximal muscles (waist, shoulder, pelvis, neck, trunk)?

reticular formation in the pons; cerebral cortex, thalamus, cerebellum

the reticulospinal tract originates in the ______ and receives info from the _____

no

does the vestibulospinal tract decussate?

yes

does the rubrospinal tract decussate?

sometimes, but usually NO

does the reticulospinal tract decussate?

yes

does the tectospinal tract decussate?

head movements in response to visual and auditory stimuli

what is the function of the tectospinal tract?

tectospinal tract

which tract controls head movements in response to visual and auditory stimuli?

superior culiculus in the midbrain; eye

the tectospinal tract has its UMN soma in the ________, and receives information from the ________

anatomical areas in the cortex of humans and primates

what are Brodmann areas?

damage to the cortex, but the rubrospinal and vestibulospinal tracts are still connected, so the animal has its upper limbs flexed and its lower limbs extended

what is decorticate rigidity?

to the cerebral cortex

an animal with decorticate rigidity had damage where?

damage below the midbrain but above the medulla, so the rubrospinal tract is inhibited and the vestibulospinal tract is still connected. so, there is extension in both the upper and lower limbs

what is decerebrate rigidity?

below the midbrain but above the pons/medulla

if an animal has decerebrate rigidity, where was the damage?

there is damage to the medulla, inhibiting the cardiorespiratory center, so the animal will die

what is flaccid/premortem rigidity?

in the medulla

an animal with flaccid/premortem rigidity has damage where?