Tract Master

Question 1

Corticospinal

Answer 1

Direction:Descending

Origin: Motor Cortex

Crossover: 90% lateral, 10 %anterior

Destination:Alpha motor neurons

Function:Skilled motor to extremities

Question 2

Reticulospinal

Answer 2

Direction:Descending

Origin: Reticular Formation

Crossover:Variable levels

Destination:Alpha and gamma motor neurons

Function:Cortical control of voluntary motor function

Question 3

Rubrospinal

Answer 3

Direction:Descending

Origin: Red Nucleus

Crossover:Immediate

Destination: Alpha and gamma motor neurons

Function:Facilitate flexors, inhibiting extensors( balance control)

Question 4

Vestibulospinal

Answer 4

Direction: Descending

Origin: Vestibular nucleus

Crossover:NONE

Destination: Alpha and gamma motor neurons

Function: Facilitate extensors and inhibit flexors( balance control)

Question 5

Lateral Spinothalmic

Answer 5

Direction:Ascending

Origin: Free nerve endings

Crossover:Immediate

Destination:Posterior central gyrus

Function:Pain, Temp

Question 6

Anterior Spinothalmic

Answer 6

Direction:Ascending

Origin: Free nerve endings

Crossover:variable levels

Destination: Posterior central Gyrus

Function:Light touch and pressure

Question 7

Posterior Column

Answer 7

Direction:Ascending

Origin: Meissner’s corpuscles, Pacinian corpuscles, muscle spindle, tendon organs

Crossover:Medula

Destination:Posterior Central Gyrus

Function:Discriminative touch, vibration sense, proprioception

Question 8

Corticobular

Answer 8

Direction:Descending

Origin: Frontal eye fields(Brodman8,6) precentral gyrus, postcentral gyrus

Crossover: Medula

Destination:Nuclei of Cranial nerve V,VII, XI, XII

Function: Controls muscle of head and face

Question 9

Pontine (Medial) Reticulospinal

Answer 9

Direction:Descending

Origin: Nuclei in the pons

Crossover:None

Destination:Ipsilateral ventromedial spinal cord

Function:stimulates flexors and extensors with predominant effect on extensors

Question 10

Medullary (Lateral) Reticulospinal

Answer 10

Direction: Descending

Origin: Magnocellular neurons medial 2/3rd of medulla

Crossover:NONE

Destination:Alpha and Gamma Motor neurons in ventral horn

Function: Powerfully suppress extensor spinal reflex activity and facilitate contraction of flexors

Question 11

Spinoreticular

Answer 11

Direction: Ascending

Origin: Collateral branches from axons running in the anterolateral system

Crossover:NONE

Destination: Reticular nuclei in Pons and Medulla

Function: Relay sensory info to reticular nuclei about pain, temp and crude touch in the trunk and limbs

Question 12

Lateral Vestibulospinal

Answer 12

Direction: Descending

Origin: Lateral Vestibular Nucleus (Input from inner ear and cerebellum)

Crossover:NONE

Destination: Alpha motor neurons of the axial limb extensor

Function:balance

Question 13

Medial Vestibulospinal

Answer 13

Direction: Descending

Origin: Medial Vestibular nucleus(input from inner ear and cerebellum)

Crossover:NONE

Destination: Alpha motor neurons in the cervical and upper thoracic levels

Function:Muscular contraction of neck in coordination with eye movement

Question 14

Dorsal Spinocerebellar

Answer 14

Direction: Ascending

Origin: Neuromuscular spindles (lower limbs)

Crossover:None

Destination:Cerebellum via inferior peduncle

Function:integrating motor with sensory

Question 15

Ventral Spinocerebellar

Answer 15

Direction: Ascending

Origin: Golgi tendon organ ipsilateral limb

Crossover: twice (level of spinal cord and at peduncles)

Destination: Cerebellum bia superior cerebellar peduncles

Function: integrating motor with sensory

Question 16

Cuneocerebellar

Answer 16

Direction: Ascending

Origin: Proprioceptor upper limbs

Crossover:NONE

Destination:Cerebellum via inferior cerebellar puduncles

Function:integrating motor with sensory