Ascending and descending tracts

Question 1

Ascending tracts: Posterior white column consist of

Answer 1

• Fasciculus GRACILIS
• Fasciculus CUNEATUS

Question 2

Ascending tracts: Lateral white column

Answer 2

• Lateral spinothalamic
• Posterior spinocerebellar
• Anterior spinocerebellar
• Spino-olivary
• Spinotectal

Question 3

Ascending tracts: Anterior white column

Answer 3

• Anterior spinothalamic
• Tectospinal

Question 4

Descending tracts : Lateral white column

Answer 4

• Lateral corticospinal tract
• Rubrospinal tract

Question 5

Descending tracts: Anterior white column

Answer 5

• Anterior corticospinal tract
• Tectospinal tract
• Vestibulospinal tract
• Olivospinal tract

Question 6

Descending tracts: Other descending tracts

Answer 6

• Reticulospinal tracts –lateral and medial
• Descending autonomic fibres

Question 6

Function Anterior spinothalamic tract:

Answer 6

Touch and Pressure

Question 7

Function Lateral Spinothalamic tract:

Answer 7

Pain and Temperature from the opposite half of the body

Question 8

Function:
Anterior & posterior Spinocerebellar tract

Answer 8

Unconscious muscle joint sense from the trunk and lower limb.

Question 8

Function:
Fasciculus gracilis
* Fasciculus cuneatus

Answer 8

Discriminative touch, vibratory sense, Conscious Proprioception (muscle joint sense)

Question 9

Function Spino-tectal tract:

Answer 9

Slow Pain, thermal & tactile information to the superior colliculus of mid brain; Helps in the spino- visual reflexes

Question 10

Function Spino- reticular tract:

Answer 10

Carrying the information of muscles, joints & skin to the reticular formation & also the slow pain

Question 11

Function Spino-olivary tract:

Answer 11

Indirect pathway to cerebellum

Question 12

Function of Sensory cortex of cerebrum:

Answer 12

localizes, discriminates and analyses different modalities of exteroceptive and proprioceptive sensations

Question 13

F. CUNEATUS (TRACT OF BURDACH)::

Answer 13

Present lateral to the fasciculus gracilis in the upper part of the cord up to the mid-thoracic level (T6)

Carries ipsilateral fibers from the upper limb & part of the trunk above the mid-thoracic level.

Question 14

F. GRACILIS (TRACT OF GALL)::

Answer 14

Present throughout the length of the spinal cord.

->Carries ipsilateral fibers from the lower limb & part of the body below the mid-thoracic level.

Question 15

Function: Fasciculus gracilis & Fasciculus cuneatus :

Answer 15

Discriminative touch, vibratory sense, Conscious Proprioception (muscle joint sense)

Question 16

Damage to Fasciculus gracilis & Fasciculus cuneatus results in what ?

Answer 16

Tabes dorsalis-Involvement of posterior white column and dorsal root in syphilitic degenerative disease

Romberg’s sign- patient is not able to tell the position or movements of his lower limbs unless he sees them.

Question 17

Receptors involved in Fasciculus gracilis & Fasciculus cuneatus -

Answer 17

• Meissner’s corpuscle – tactile receptors
• Golgi-Mazzoni corpuscle – senses vibratory pressure and touch
• Pacinian corpuscle – senses vibration and pressure

Question 18

Function of Lateral Spinothalamic tract:

Answer 18

Pain & Temperature from the opposite half of the body

Question 19

Function of Anterior spinothalamic tract:

Answer 19

Light touch and pressure from the contralateral side of the body

Question 20

Order neurons for Lateral spinothalamic tract:

Answer 20

• 1st order neuron: posterior root ganglion
• 2nd order neuron: substantia gelatinosa
• 3rd order neuron: ventral posteriolateral nucleus of the thalamus

Question 21

Order neurons for Anterior spinothalamic tract:

Answer 21

• 1st order neuron: posterior root ganglion
• 2nd order neuron: substantia gelatinosa
• 3rd order neuron: ventral posteriolateral nucleus of the thalamus

Question 22

Lateral spinothalamic tract become superficial in what region ?

Answer 22

the cervical region
-> cordotomy can be performed safely at this level to relieve the pain in the opposite half of the body

Question 23

Function of Posterior spinocerebellar tract:

Answer 23

• Begins at the level of the T1 to L2 segment from the axons of the Clark’s column (posterior spinocerebellar)
• Unconscious muscle joint sense from the trunk and lower limb

Question 24

Function of Anterior spinocerebellar:

Answer 24

Begins at the level of the L2 or L3 segment from the axons of the spinal border cells (anterior spinocerebellar ).
This tract carries unconscious muscle joint sense from the trunk and lower limb, fibres of this tract arise in the thoracic and lumbar levels

Question 24

spinocerebellar tracts carry what information?

Answer 24

unconscious proprioceptive information
->help our brain co-ordinate and refine motor movements.

Question 25

Posterior spinocerebellar tract carry what information?

Answer 25

Carries proprioceptive information from the lower limbs to the ipsilateral cerebellum.

Question 26

Cuneocerebellar tract carry what information?

Answer 26

Carries proprioceptive information from the upper limbs to the ipsilateral cerebellum.

Question 27

Anterior spinocerebellar tract carry what information?

Answer 27

Carries proprioceptive information from the lower limbs. The fibres decussate twice – and so terminate in the ipsilateral cerebellum.

Question 28

Rostral spinocerebellar tract carry what information?

Answer 28

Carries proprioceptive information from the upper limbs to the ipsilateral cerebellum.