Pathways

Question 1

Ascending Pathways - Dorsal Column

Answer 1

> Touch
Body position
weight distribution

Pathway:
> Receptor to spine via 1st order neuron
> Delivers to Cuneatus (UL) or Gracilis (LL)
> Ascends to thalamus (2nd order)
> Crosses in medulla
> Ascends to sensory cortex via 3rd order

Question 2

Ascending Pathways - Spino-thalamic tract

Answer 2

> Lateral = Pain + temperature
Anterior = itch/tickle/pressure/vibration

Pathway 
> Receptor to spine = 1st order
> Ascends to Thalamus = 2nd order 
> Crosses on entry to spinal cord 
> Thalamus to sensory cortex = 3rd order

Question 3

Ascending Pathways - Spinocerebellar

Answer 3

> Balance
Joint position

Pathway
> Posterior - doesn’t cross (enters via inferior peduncle)
> Anterior - will either not cross or cross 2x
- enters via superior peduncle

Question 4

Descending Pathways - Pyramidal (corticospinal)

Answer 4

> Lateral = extremities
Anterior = axial

Pathway 
> Descends from cortex to medulla (via cerebral peduncle)
> arranges in bundles @ medulla 
> 10-20% - Anterior = descend + cross 
> 80-90% - Lateral = cross + descend

Question 5

Descending Pathways - Reticulospinal

Answer 5

> Reticular formation associated with pons + medulla
Lateral tract = flexor reflexes
Medial tract = extensor reflexes

Question 6

Descending Pathways - Vestibulospinal

Answer 6

> Position of head/neck/trunk
Balance
*Uncrossed tract

Question 7

Descending Pathways - Tectospinal

Answer 7

> Response to visual stimuli
associated with midbrain
*Crosses at origin

Question 8

Descending Pathways - Rubrospinal

Answer 8

> Control of fine movement
associated with midbrain
*Crosses at origin