Ascending Systems 2

Question 1

sensory first order neuron location

Answer 1

peripheral process and DRG in PNS

central process enters cord

Question 2

sensory first order synapse location

Answer 2

cord or brainstem

Question 3

sensory second order neuron synapse

Answer 3

ventral posterolateral thalamus

Question 4

sensory third order neuron synapse

Answer 4

cortex

Question 5

location of sensory decussation

Answer 5

at the gracilis or cuneate nuclei

Question 6

DCML does

Answer 6

discriminatory touch
position
vibration

Question 7

location of second order synapse above T6

Answer 7

cuneate fasiculus

Question 8

location of second order synapse below T6

Answer 8

gracilis fasiculus

Question 9

in what do the fibers decusate

Answer 9

internal arcuate fibers

Question 10

what forms medial lemniscus

Answer 10

internal arcuate fibers from the gracilis/cuneate nuclei

Question 11

in what do fibers travel from the VPL to the cortex

Answer 11

posterior limb of the internal capsule

Question 12

what is the post synaptic dorsal column system

Answer 12

alternate route of DCML information- fibers synapse immediately upon entering cord
for pain sensation

Question 13

medial division of the dorsal root entry zone

Answer 13

large heavily myelinated fibers

synapse at laminae III-V

Question 14

lateral division of the dorsal root entry zone

Answer 14

small axons with little to no myelination

join Lissauer’s tract

Question 15

somatotrophic arrangement of medial lemniscus

Answer 15

legs are most anterior
trunk
arms more posterior

Question 16

DCML blood supply

Answer 16

posterior spinal arteries

Question 17

defect of peripheral nerve damage

Answer 17

loss of all modalities in the nerve field distribution

Question 18

defect of dorsal root damage

Answer 18

loss of all modalities in the dermatome distribution

Question 19

defect in the CNS

Answer 19

depends on the lesion location as to what side affected and severity

Question 20

modality

Answer 20

type of sensation

Question 21

topography

Answer 21

where

Question 22

level of sensation

Answer 22

quality

Question 23

DCML defect results in

Answer 23

full loss of vibratory sensation

partial loss of everything else (covered by other systems)

Question 24

romberg sign

Answer 24

difficult standing with eyes close

Question 25

common cause of ataxia

Answer 25

loss of proprioception in feet

Question 26

Frederich’s ataxia

Answer 26

autosomal reessive mutation affecting the DCML

Question 27

tabes dorsalis

Answer 27

associated with late stage neurosyphallis

Question 28

ataxia

Answer 28

lack of muscle movement coordination