Ascending Pathways - SRS

Question 1

Identify the blocked out structures

Answer 1

Starting at 8:00…

Anterolateral System

Ventral Spinocerebellar tract

Dorsal spinocerebral tract

Fasciculus Cuneatus

Fasciculus Gracilis

Question 2

What three categories of information do spinal cord tracts carry?

Answer 2

1. Discriminatory
2. Reflexive
3. Postural

Question 3

The spinal cord has tracts that carry discriminatory information which determines type, location and intesity of the stimulus. What are the tracts that carry this?

Answer 3

1. Dorsal columns/medial lemniscus (DCML)
   
   • Fasciculus gracilis
   • Fasciculus cuneatus
2. Anterolateral system
   
   • ​​Neospinothalamic

Question 4

The spinal cord has tracts that carry reflexive information which activates responses to create behavioral state change with appropriate stereotyped motor responses. What are the names of these tracts?

Answer 4

1. Anterolateral system
   
   • ​​Paleospinothalamic
   • [spinoreticular]
   • [spinomesencephalic]

​

Question 5

What senssation types are carried by the discriminatory tracts?

Answer 5

Tactile (temperature, blunt/sharp, locality)

Question 6

The spine carries postural information regarding joints, tendon and muscle position. What tracts do this?

Answer 6

•Spinocerebellar tracts
–Cuneocerebellar
–[Rostral spinocerebellar]
–Dorsal spinocerebellar
–Ventral spinocerebellar

Question 7

Fast, wide diameter axons travel to white matter in the?

Answer 7

Posterior funiculi

Question 8

Slower, thin-diameter axons travel to what structures in the dorsal horn?

Answer 8

Lamina I-VI

Question 9

How many neurons long are the discriminatory pathways?

Answer 9

3

Question 10

How many neurons long are postural pathways?

Answer 10

2

Question 11

What are the types of information in the pathways of the dorsal columns? What are the two portions of this pathway?

Answer 11

Tactile discrimination, conscious proprioception

Posterior columns and medial lemniscus

Question 12

What are the point of origin receptors for the dorsal columns?

Answer 12

–Meissner’s corpuscles, merkel’s disks, pacinian corpuscles, ruffini’s endings in skin muscle spindles, golgi tendon organs in muscles, joints and tendons

Question 13

Where are the primary cell bodies of the dorsal columns located?

Answer 13

Dorsal root ganglia (DRG)

Question 14

Where is the first synapse for the dorsal columns?

Answer 14

–Nucleus cuneatus (for upper body) and nucleus gracilis (for lower body), in caudal medulla

Question 15

Where do neurons for the dorsal columns enter the spinal cord?

Answer 15

Medial aspect of dorsal horn

Question 16

Where do discriminatory fiber tracts decussate?

Answer 16

Internal arcuate fibers ventral to cuneatus and gracilis (becomes “medial lemniscus”)

Question 17

Where is the second synapse of the dorsal columns?

Answer 17

Ventral posteriolateral (VPL) Nucleus of the Thalamus

Question 18

What is the final destination of the dorsal columns?

Via what structures?

Answer 18

The primary somatosensory cortex (Via internal capsule and corona radiata)

Question 19

Dermatomes segregate cuneatus from gracilis. What body segments do each represent?

Answer 19

Cuneatus - Thoracic and Cervical

Gracilis - Lumbar and Sacral

Question 20

What are the nuclei of the Cuneatus and Gracilis seperated by?

Answer 20

Posterior intermediate septum

Question 21

Identify where the thoracic, sacral, lumbar and cervical tracts are in this spinal segment.

Answer 21

Question 22

Identify the indicated structures. What portion of the spinal cord is this?

Answer 22

Medulla

Question 23

Identify the tagged structures. Where is this section from?

Answer 23

Thalamus

Question 24

Describe the somatotopy of the primary somatosensory cortex.

Answer 24

See attachment

Question 25

The third pathway takes the anterolateral system. What tract is this?

Answer 25

Neospinothalamic tract

Question 26

What type of information is conveyed in the neospinothalamic tract?

Answer 26

Pain Temperature Poorly localized touch

Question 27

What are the point of origin receptors involved in the neospinothalamic tract?

Answer 27

Free Nerve endings (TRP channels) in skin, viscera, muscles

Question 28

Where are the primary cell bodies of the neospinothalamic tract located?

Answer 28

DRG

Question 29

Where is the first synapse for the neospinothalamic tract?

Answer 29

Lamina I-VI

Question 30

What is the path into the spinal cord and through it that the neospinothalamic tract takes?

Answer 30

1. dorsal horn (Lissauer’s Fassciculus to ascend at least 1 segment) 2. after 1st synapse, travels through anterior white commissure 3. ascends through anterolateral spinothalamic tract

Question 31

Where does the neospinothalamic tract fiber decussate?

Answer 31

In the anterior white commissure after the first synapse

Question 32

Where is the second synapse for the neospinothalamic tract?

Answer 32

Ventral Posteriolateral Nucleus (VPL) of the Thalamus

Question 33

What is the final destination of the neospinothalamic tract?

Answer 33

–Primary somatosensory cortex (via internal capsule and corona radiata)

Question 34

Identify the tagged structures

Answer 34

Question 35

What type of information is carried in the paleoospinothalamic tract?

Answer 35

Poorly localized pain

Question 36

What is the point of origin receptor for the paleospinothalamic tract?

Answer 36

Free nerve endings (TRP channels) in skin, viscera, muscles

Question 37

Where are the primary cell bodies of the paleoospinothalamic tract?

Answer 37

DRG

Question 38

Where is the first synapse for the paleoospinothalamic tract?

Answer 38

Lamina I-VI

Question 39

Describe the paleospinothalamic tract from the point it enters the spinal column to its ascent.

Answer 39

1. dorsal horn (Lissauer’s Fassciculus to ascend at least 1 segment), 2. after 1st synapse, travels bilaterally, 3. ascends through anterolateral spinothalamic tract

Question 40

Where does the paleospinothalamic tract decussate?

Answer 40

It doesn't necessarily, but the fibers that do decussate do so through the anterior white commissure.

Question 41

Where is the second synapse for the paleoospinothalamic tract?

Answer 41

Intralaminar nuclei of the Thalamus

Question 42

What is the final destination of the paleoospinothalamic tract?

Answer 42

–Bilateral cortex, poorly localized (includes cingulate gyrus and insula)

Question 43

Identify the indicated structures

Answer 43

Question 44

Identify the blocked out labels.

Answer 44

Question 45

What four tracts make up unconscious proprioception?

Answer 45

* Dorsal spinocerebellar * Ventral spinocerebellar * Rostral spinocerebellar (?) (not often in humans) * Cuneocerebellar

Question 46

What kind of information do the fifth and 6th pathways carry? (Dorsal Spinocerebellar and cuneocerebellar)

Answer 46

–**_Unconscious_** proprioception

Question 47

What receptors are involved in the 5th and 6th pathways? (Dorsal Spinocerebellar and cuneocerebellar)

Answer 47

Muscle spindles and golgi tendon organs in muscles, joints and tendons

Question 48

Where are the primary cell bodies of the dorsal spinocerebellar and cuneocerebellar pathways located?

Answer 48

DRG

Question 49

What is the location of the first synapse for the dorsal spinocerebellar and cuneocerebellar tracts?

Answer 49

**Spinocerebellar - **Clarke's nucleus (AKA nucleus dorsalis) of thoracic cord. **Cuneocerebellar - ** Accessory cuneate nucleus in the caudal medulla

Question 50

Where do the 5th and 6th pathways enter/travel in the spinal cord?

Answer 50

Posterior funiculi (hitchhikes with the dorsal columns)

Question 51

Where do the spinocerebellar and cuneocerebellar pathways decussate?

Answer 51

They do not.

Question 52

Where is the second synapse for the dorsal spinocerebellar and cuneocerebellar pathways?

Answer 52

–vermis/paravermis of the cerebellum via inferior cerebellar peduncle

Question 53

What is the final destination of the spinocerebellar and cuneocerebellar tracts?

Answer 53

–Deep cerebellar nuclei (via purkinje cells)

Question 54

Identify the red circle

Answer 54

Question 55

When below C8, unconsious proprioceptive information hitchhikes on the posterior column. Where does it synapse? Where is it visible?

Answer 55

–Synapses in Lamina VII –Visible L3 to C8 •CLARKE’S COLUMN/CLARKE’S NUCLEUS/NUCLEUS DORSALIS

Question 56

What is the structure circled in red?

Answer 56

Accessory Cuneate nucleus

Question 57

When above C8, the cuneocerebellar tract synapses in the?

Answer 57

•accessory/external/lateral cuneate nucleus

Question 58

Identify the indicated structures

Answer 58

Question 59

Identify indicated structures

Answer 59

Question 60

Identify indicated structures

Question 61

What do the ventral spinocerebellar and rostral spinocerebellar pathway carry, information wise?

Answer 61

Broad integrated information from the entire limb

Question 62

What type of information is carried by the ventral spinocerebellar tract?

Answer 62

–**_Unconscious_** proprioception

Question 63

What are the receptors associated with the ventral spinocerebellar tract?

Answer 63

–muscle spindles, golgi tendon organs in muscles, joints and tendons

Question 64

Where are the primary cell bodies of the ventral spinocerebellar pathway located?

Answer 64

DRG

Question 65

Where is the first synapse of the ventral spinocerebellar?

Answer 65

Lamina VII.

Question 66

Where does the ventral spinocerebellar pathway enter the spinal cord/travel?

Answer 66

Posterior funiculi

Question 67

Where does the ventral spinocerebellar pathway decussate?

Answer 67

Immediately in the spinal cord

Question 68

Where is the second synapse for the ventral spinocerebellar pathway? What is unusual about this pathway after the second synapse?

Answer 68

–vermis/paravermis of the cerebellum via superior cerebellar peduncle. **Will then decussate again!**

Question 69

What is the final destination of the ventral spinocerebellar tract?

Answer 69

Deep cerebellar nuclei (via purkinje cells)

Question 70

Identify the indicated structure. What is the spinal section this is from?

Answer 70

Upper Cervical

Question 71

Patient has a lesion of the right fasciculus cuneatus at C2. Tell me all of the sensory systems affected, and on which side of the body…

Answer 71

1. Right-sided, upper-limb tactile discrimination, 2. conscious proprioception 3. unconscious proprioception of individual muscles/tendons

Question 72

Patient has a Lesion of Lamina VII in left thoracic spinal cord. Tell me all of the sensory systems affected, and on which side of the body…

Answer 72

•Left sided unconscious proprioception of lower limbs (individual fibers)

Question 73

Patient has Allodynia (pain due to a stimulus that usually does not provoke pain) on the right side of the leg. Name the possible areas where there might be a lesion…

Answer 73

1. Right sided peripheral axons/free nerve endings, 2. right sided dorsal horn (Lamina I-V), 3. Anterior white commissure, 4. Left sided Lateral spinothalamic tract, 5. left sided VPL thalamus, 6. left sided primary somatosensory cortex