Lecture 3: Dorsal Column Sensory Flashcards

1
Q

What are alpha-beta nerve cells involved with?

A

Touch, vibration, conscious proprioception

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2
Q

Where do alpha beta nerve cells run in the spinal cord?

A

Dorsal funiculus

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3
Q

Hair cell receptors

A

Unencapsulated; hairy skin; deep field; activated via hair movement

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4
Q

Meissner’s Corpuscles

A

Hairy and glabrous skin; Surface small field; activated by light touch, texture, low freq vibrations; adapts quickly

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5
Q

Merkel’s Disk

A

Hairy and glabrous skin; Surface small field; activated by light touch and pressure; only nerve cell in epidermis; adapts slowly

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6
Q

Pacinian Corpuscles

A

Hairy and glabrous skin; deep large field, activated by deep pressure and high freq vibrations; like onion; adapts quickly

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7
Q

Ruffini endings

A

Glabrous (hairy?) skin only; deep large field; activated by deep pressure and stretch; adapts slowly

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8
Q

How do people tell where their joints and limbs are?

A

Alpha-beta nerves are located in joints and convey conscious proprioception to brain

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9
Q

What receptors are involved most in 2 point discrimination?

A

Meissners and Merkels because both are superficial; highest concentration in lips and fingertips

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10
Q

Faciculus Gracillis

A

Have axons from T7 and below; located medially in dorsal funiculus

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11
Q

Faciculus Cuneatus

A

Have axons from T6 and above, located more laterally in dorsal funiculus

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12
Q

How are axons from body parts arranged in the dorsal column?

A

Lower body parts are located more medially

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13
Q

What will happen with a lesion in the dorsal column?

A

Loss of ipsilateral touch, vibration, and conscious proprioception

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14
Q

Where do fasciculus cuneatus axons synapse?

A

Ipsilateral nucleus cuneatus

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15
Q

Where do fasciculus gracillis axons synapse?

A

Ipsilateral nucleus gracillis

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16
Q

Where do touch, vibration, and conscious proprioception axons cross the midline?

A

Internal arcuate in medulla; go to contralateral thalamus via medial lemniscus

17
Q

Where do touch, vibration, and conscious proprioception nerve fibers go after passing through the thalamus?

A

Contralateral somatosensory cortex

18
Q

How is the somatosensory cortex arranged?

A

Lower limbs medial; face more lateral

19
Q

Romberg Sign

A

Swaying when closing eyes with feet together since so conscious proprioception

20
Q

Dorsal column lesion deficits

A

Positive Romberg, Lhermitte’s Sign (shooting pain when bending neck down), Agraphesthesia (number on hand), Astereognosia (ID by touch)