5.2 Sensory & Motor Pathways Flashcards

1
Q

What receptors are on fingers and palm of hand, plantar surface of foot and toes?

A

Meissner’s corpuscles

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2
Q

What receptors are sensitive to touch and vibration?

A

Meissner’s corpuscles

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3
Q

What receptors are on lips, distal parts of extremities?

A

Merkel’s receptors

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4
Q

What receptors are sensitive to pressure stimuli, and low frequency vibration?

A

Merkel’s receptors

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5
Q

What receptors are found on hands and feet, walls of mesenteries, vessel walls, periosteum, and joint capsules?

A

Pacinian corpuscles

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6
Q

What receptors are sensitive to rapid indentation of skin (high frequency vibration)?

A

Pacinian corpuscles

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7
Q

What receptors are widely distributed in dermis layer of skin?

A

Ruffini’s corpuscles

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8
Q

What receptors are sensitive to stretch?

A

Ruffini’s corpuscles

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9
Q

Where are proprioceptors located?

A

in joint capsules

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10
Q

Where are cell bodies that mediate touch and conscious proprioception located; first order neurons of DCML?

A

dorsal root ganglia

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11
Q

What fibers are located in the fasciculus gracilis?

A

central axons of sensory neurons (from receptors that mediate tactile sensation and proprioceptors of joints) at and below T6

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12
Q

What fibers are located in the fasciculus cuneatus?

A

central axons of sensory neurons (from receptors that mediate tactile sensation and proprioceptors of joints) above T6

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13
Q

Where do the fibers of the fasciculus gracilis and cuneatus synapse?

A

Upon 2nd order neurons in the dorsal column nuclei of the medulla (nucleus gracilis and nucleus cuneatus)

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14
Q

Do the fibers in the fasciculus gracilis and cuneatus tracts stay on the same side or do they cross to the contralateral side?

A

ascend ipsilaterally in the spinal cord

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15
Q

Where do the fibers of the nucleus gracilis and cuneatus decussate?

A

at the level of the medulla

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16
Q

What do the fibers of the nucleus gracilis and cuneatus form after they decussate?

A

medial lemniscus

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17
Q

Where do fibers from the medial lemniscus travel and project to?

A

Ascend through medulla, pons and midbrain, then project to 3rd order neurons in the VPL nucleus of thalamus.

18
Q

Where do the 3rd order neurons of the VPL project to?

A

primary somatosensory cortex = postcentral gyrus

19
Q

Where are lower motor neurons for the head from?

A

motor neurons of cranial nerves

20
Q

Where are lower motor neurons for the body from?

A

in the ventral horn of the spinal cord

21
Q

Where do upper motor neurons arise?

A

cerebral cortex

22
Q

Upper motor neurons of the Corticospinal tract from the cerebral cortex project to lower motor neurons of what?

A

spinal cord (voluntary control for movement of body)

23
Q

Upper motor neurons of the Corticobulbar tract from the cerebral cortex project to lower motor neurons of?

A

brainstem (CN i.e. facial motor nucleus, trigeminal m. n.) and (voluntary control fro movement)

24
Q

What participates in control of movement by receiving inputs from cerebral cortex and feeding back signals to different regions of the frontal cortex involved in initiation of movement?

A

Basal ganglia

25
Q

How does the basal ganglia play a role in motor function?

A

modulates activity of upper motor neurons

26
Q

What receives inputs from and gives outputs to most parts of CNS that contribute to motor functions?

A

cerebellum

27
Q

How does the cerebellum play a role in motor function?

A

Serves as the principal integrator of motor function

28
Q

What regions influence the pre central gyrus?

A

(1) motor activity regulation from several regions of CNS including cerebellum and basal ganglia via VL (2) somatosensory afferents from postcentral gyrus via VPL

29
Q

Where does the primary motor cortex (pre central gyrus) project to and via which pathways? (2)

A

(1) ventral horn of spinal cord at all levels via corticospinal tract
(2) lower motor neurons composing cranial motor nuclei of brainstem via corticobulbar tract

30
Q

What is the result of activation of the descending fibers of the primary motor cortex?

A

muscle contractions of individual muscles and controls the tone of these muscles

31
Q

What area do inputs received from basal ganglia primarily go to?

A

Supplemental motor area via VL

32
Q

What area do inputs received from the cerebellum primarily go to?

A

premotor cortex via VL

33
Q

Where do the Premotor and Supplemental Motor Cortices also receive inputs from?

A

Posterior parietal cortex, including somatosensory inputs from post central gyrus and from vestibular and visual areas

34
Q

Where do the premotor and supplemental motor cortices project to? and via which fiber pathway?

A

corticospinal tract to ventral horn

35
Q

What is the result of activating fibers of the premotor and supplemental motor cortices?

A

coordinate voluntary movements, sequencing of response patterns that are essential for producing movements

36
Q

What results from the inability to initiate specific, purposeful movements; moving planning deficits?

A

Apraxia

37
Q

What are the 3 different regions of origin of the Corticospinal tract?

A

pre central gyrus (primary motor cortex), premotor cortex, and supplemental motor area

38
Q

Axons of the corticospinal tract travel through the white matter of the cortex, followed by what 2 structures to reach the lower brainstem?

A

internal capsule (posterior limb) and then through the crus cerebri (midbrain)

39
Q

Where does the Corticobulbar tract arise from?

A

lateral aspect of primary motor cortex (pre central gyrus)

40
Q

What are the 2 exceptions to the bilateral innervation of the Corticobulbar pathway?

A

contralateral innervation of the ventral cell groups of motor nucleus of CN VII and CN XII

41
Q

Axons of the corticobulbar tract travel through the white matter of the cortex, followed by what 2 structures before exiting at their appropriate levels of the brainstem?

A

internal capsule (gene) and crus cerebri (midbrain)