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Flashcards in Spinal cord 2 Deck (28):
1

What are the Ascending (Sensory) Tracts?

  1. Dorsal column/medial leminiscus tract

  2. Ventral spinothalamic tract (Anterior)

  3. Lateral spinothalamic tract 

  4. Dorsal spinocerebellar tract (propioception)

  5. Ventral spinocerebellar tract (propioception)

  6. Cuneocerebellar tract (propioception)

2

What information do ascending tracts convey?

ascending tracts go from where to where?

sensory information

from the body to the CNS

3

ascending systems are composed of three types of

neurons, which are these?

 1st, 2nd, and 3rd order neurons

4

what can be said about 1st order neurons of ascending tracts?

The cell bodies of these are located in the dorsal root ganglion; the peripheral portion of this nerve forms the sensory nerve ending, while a central process enters the spinal cord (via the posterior root) to synapse on a…

 

5

what can be said about 2nd order neurons of ascending tracts?

  Cell body located in spinal cord or brainstem; axon ascends, crosses the midline, and synapses on a…

 

6

what can be said about 3rd order neurons of ascending tracts?

Cell bodies usually located in thalamus, axons ascend to sensory areas of cortex.

7

identify the ascending tracts

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8

identify the tracts

which color represents: ascending, descending, bidirectional tracts

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9

what information does the anterolateral spinothalamic tract convey?

Conveys pain, temperature and basic tactile sensation

10

into what 2 parts is the anterolateral spinothalamic tract divided into?

what do each do?

Lateral: pain and temperature

Anterior: for crude touch

 

11

what are the 2 divisions of the anterolateral spinothalamic tract?

Define each.

1) neospinothalamic: Direct pathway to thalamus and on to primary somatosensory cortex

• for sensaiton of pain

• same paint that everyone experiences

2) paleospinothalamic: Indirect pathway, does go to thalamus and cortex, but gives afferents along the way to reticular formation.  Cortical locations are more widespread, including cingulate gyrus and limbic structures.

• ‘Affective’ or emotional and ‘arousal’ (subjective) component of pain

• varies between individuals

12

what is the Tract of Lissauer?

what should be known about this tract?

branching from the anterior and lateral spinothalamic tract

  • dorsal horn has ‘entry zone’ for axons. 
  • Lateral spinothalamic axons branch 1-3 segments up and down here before synapsing with 2nd order neurons.

13

what type of information does Dorsal Column/Medial Lemniscus relay?

Mediates discriminative touch, vibration, muscle joint sense.

14

Damage to the spinothalamic tract on C5-C6, on the right will show symptoms in what side and form where to where?

on the left from C6 and down

15

where do we find 2nd order neurons from the dorsal column tract?

2nd order neurons will synapse where?

in the medulla

in the thalamus

16

where are 2nd order neurons located in the spinothalamic tract?

in the spinal cord, thats why they cross right away

17

what does the fasciculus gracilis contain?

what does the Fasciculus cuneatus contain?

 

which is located medially and which is lateral?

  • contains axons arising from dorsal root ganglia at T7 and below.
  • contains axons from dorsal root ganglia at T6 and above

 

gracilis = medially

cuneatus = lateral

18

where is the Nucleus gracilis and cuneatus located?

what happens here?

  •  located in caudal medulla
  • Axons decussate as arcuate fibers, ascend to VPL of thalamus.

19

2nd order neurons that cross, will do so how?

1 or 2 vertebrae below the lesion

20

where does fasiculus cuneatus start?

T6 and above

21

which here is the posterior cerebellar tract and which is the anterior cerebellar tract?

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22

what does the posterior spinocerebellar tract do?

how many neurons does it use?

where do its neurons synapse?

 mediates information of proprioception from the lower extremities

two:

1st order neuron: synapse in nucleus dorsalis

2nd order neuron: ascend ipsilaterally then enter cerebellum via inferior cerebellar peduncles.

 

23

what does the anterior spinocerebellar tract do?

how many neurons does it use?

where do its neurons synapse?

transmits information from the thoracolumbar levels. 

two:

1st order neurons synapse with interneurons in the dorsal horn; interneurons send axons to 2nd order neurons in the lateral and ventral horns.

2nd order neurons cross via the ventral white commissure, ascend contralaterally and enter the cerebellum via the superior cerebellar peduncle. They then cross back to the ipsilateral cerebellum.

24

Spinotectal, Spinoreticular, and Spino-olivary Tracts are for what?

feedback 

25

what do we expect with Spinothalamic tract lesion?

what do we expect with Dorsal column system lesion?

what do we expect with Spinocerebellar tract lesion?

  • Contralateral loss of pain and temperature, and simple tactile sensations, 1-2 below the level of the lesion.
  • Ipsilateral loss of vibratory sense, position, and tactile discrimination.
  • Selective damage to these tracts (i.e. without UMN damage) is rare.  Symptoms when damaged would include loss of propioception and ataxia (typically ‘masked’ by the UMN damage:  can’t see ataxia if the patient can’t walk). 

26

what is syringomyelia?

where does it usually happen?

what is the main symptom?

what neuron is being inhibited in order to cause the main symptom?

is there damage to the tract affected?

if the condition worsens, what symptoms can be seen?

  • Developmental abnormality in formation of the central canal.
  • Usually occurs in cervical segments.
  • capelike distribution of pain and temperature loss
  • the 2nd order neuron 
  • no, the tract is intact yet the 2nd order neuron is being inhibited
  • loss of sensation (or touch), paralysis and atrophy of upper limb muscles.

     

27

What is transverse myelitis? what does it result in?

what symptoms do we see?

 

inflammation fo the spinal cord caused by infection with herpes or syphilis, resulting in demyelination

lower motor neuron damage (similar to spinal cord transection)

28

what is the difference? what disease can we see in one of these?

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up: normal

down: transverse myelitis

  • white matter is dark and white patches inside the white matter is demyelinization