Sensory 3: somatic Sensory Pathways

Question 1

sensations carried on Dorsal Column pathway

Answer 1

Mechanoceptive:
* Fine touch
* Fine pressure
* Vibration
* Stereognosis
* Position (propreoception)

Question 2

Afferent fibers of Dorsal Column pathway

Answer 2

• A Beta (except Proprioception)
• A alpha (for proprioception)

Question 3

Receptors for Dorsal Column pathway

Answer 3

Mechanoreceptors

Question 4

1st Order neurone of Dorsal Column Pathway

Answer 4

DRG postganglionic fibers ascend upwards Ipsilaterally as cuneate and gracile tract to reach medulla

Question 5

2nd Order Neurone of Dorsal Column pathway

Answer 5

Upon reaching Medulla, fibers from gracile and cunate Nuclei Cross to the other side to VBN & PVN of thalamus

Question 6

3rd Order Neurone Of Dorsal Column pathway

Answer 6

Fibers from thalamus reach somatic sensory cortex ipsilaterlly

Question 7

Sensations of Lateral spinothalamic Tract

Answer 7

Pain & Temperature

Question 8

Afferent fibers of Lateral spinothalamic Tract

Answer 8

C fibers

Question 9

Receptors of Lateral spinothalamic tract

Answer 9

Free Nerve endings

Question 10

1st order neurone of Lateral spinothalamic

Answer 10

DRG postganglionic fibers to ipsilateral dorsal (posterior) horn cells

Question 11

2nd order neurone of Lateral Spinothalamic tract

Answer 11

crosses from dorsal horn cells in front of the Central Canal to opposite site and ascend to PVN of thalamus of that opposite side

Question 12

3rd Order neurone of Lateral Spinothalamic tract

Answer 12

from PVN of thalamus to Somatic sensory cortex ipsilaterally

Question 13

Sensations of ventral spinothalamic tract

Answer 13

Crude sensations + itching & tickling

Question 14

Afferent fibers of ventral spinothalamic tract

Answer 14

A delta fibers

Question 15

Receptors of ventral spinothalamic tract

Answer 15

Free nerve endings

Question 16

1st order neurone of ventral spinothalamic tract

Answer 16

from DRG to Dorsal Horn cells ipsilaterally

Question 17

2nd order neurone of ventral spinothalamic tract

Answer 17

from Dorsal horn cells, crossing central canal (further from the canal than Lateral spinothalamic) to the opposite and ascends to thalamus on that opposite side

Question 18

3rd Order neurone ventral spinothalamic tract

Answer 18

• Ascends from PVN of thalamus to Somatic Sensory Coretx ipsilaterally

Question 19

Role of Thalamus in sensory perception

Answer 19

1. all sensory tracts, except olfcotry, synapse in thalamis
2. Thalamus feels sensations crudely , therefore person can be crudely aware of sensagtion but cannot precievea all fine details