Spinal Cord Ascending Systems

Question 1

What information is relayed on the dorsal column pathway (DCP)?

Answer 1

Proprioception
2 Point Discrimination
Vibration Sense

GSA function

Question 2

What are the fast adapting receptors?

Answer 2

Hair Follicle
Meissner’s Corpuscle
Pacinian Corpuscle

Question 3

What are the slow reacting receptors?

Answer 3

Free Nerve Endings
Merkel's Disk
Ruffini Ending
Joint Receptor
Neuromuscular Spindle
Golgi Tendon Organs

Question 4

What do free nerve endings detect?

Answer 4

Pain and Temperature

Question 5

What do Merkel’s Disk detect?

Answer 5

Touch

Question 6

What do hair follicles detect?

Answer 6

Touch

Question 7

What do Meissner’s Corpuscles detect?

Answer 7

2 point discrimination

Question 8

What do Pacinian Corpuscles detect?

Answer 8

Vibration

Question 9

What do joint receptors detect?

Answer 9

Joint Position

Question 10

What do neuromuscular spindles detect?

Answer 10

Limb and muscle stretch

Question 11

What do Golgi Tendon Organs detect?

Answer 11

Muscle tension

Question 12

What do Ruffini Corpuscles detect?

Answer 12

Stretch and pressure

Question 13

Describe the pathway of the DCP.

Answer 13

Receptors ->
Gray Matter ->
Fasciculus Gracilis (medial - lower body) OR Fasciculus Cuneatus (lateral - upper body) ->
Nucleus Gracilis/Cuneatus (SYNAPSE) ->
Thalamus as the Ventral Posterolateral Nucleus (SYNAPSE)

Question 14

What are other names for the motor cortex?

Answer 14

Area 4

Precentral Gyrus

Question 15

What are other names for the sensory cortex?

Answer 15

Area 312

Postcentral Gyrus

Question 16

Descibe the 3 orders of neurons in the DCP.

Answer 16

1st Order - go from the limb to the nucleus cuneatus/gracilis and synapse

2nd Order - cross the midline through the medial lemniscus and synapse at the VPL in the thalamus

3rd Order - synapse on the post central gyrus of the sensory cortex

Question 17

What are the fibers to the medial lemniscus that cross the midline called?

Answer 17

Internal Arcuate

Question 18

What is Romberg’s sign (tabes dorsalis)?

Answer 18

It is positive if patient requires vision to stand. It appears positive in sensory ataxia.

Question 19

Describe the pathway of the spinothalamic tract.

Answer 19

Receptors ->
Gray Matter (SYNAPSE) crosses midline ->
Neospinothalamic Tract ->
Thalamus at the VPS (SYNAPSE)

Question 20

Describe the effects of syringomyelia.

Answer 20

As the tub expands in the spinal cord, it will hit the STT and affect the arms first and move downwards.

Question 21

What are the effects of the Brown-Sequard lesion?

Answer 21

Pain and temperature sensation are lost from the opposite side of the lesion and proprioception from the same side.

Question 22

What do the spinocerebellar tracts detect?

Answer 22

Unconscious proprioception

Question 23

Where are the spinocerebellar tracts located?

Answer 23

On the very lateral part of the white matter

Question 24

What do the spinocerebellar tracts arise from?

Answer 24

Clark’s Nucleus (Nucleus Dorsalis)

Question 25

What information do the spinocerebellar tracts relay?

Answer 25

Muscle Stretch

Question 26

Describe the path of the dorsal spinocerebellar tract.

Answer 26

Receptor -> 
Nucleus Dorsalis in the Gray Matter (SYNAPSE) ->
DSCT in White Matter ->
Inferior Cerebellar Peduncle ->
Cerebellum (SYNAPSE)

Question 27

Describe the path of the cuneocerebellar tract.

Answer 27

Receptor -> 
Gray Matter ->
Fasciculus Cuneatus ->
Accessory Cuneate Nucleus (SYNAPSE) ->
Inferior Cerebellar Peduncle ->
Cerebellum (SYNAPSE)

Question 28

Where is the DSCT located?

Answer 28

At the levels of C8 - L2

Question 29

What is the function of the ventral spinocerebellar tract?

Answer 29

It monitors the activity of the interneurons in the gray matter and relays the information to the cerebellum

Question 30

What is the pathway of the VSCT?

Answer 30

Gray Matter (crosses midline) ->
VSCT on White Matter) ->
Superior Cerebellar Peduncle (crosses midline ->
Cerebellum (SYNAPSE)