Ascending & Descending Pathways Flashcards
Name the two main ascending tracts
- Dorsal Column
- Spinothalamic tract
What kinds of sensory information is transmitted through the dorsal column?
- Fine touch
- Two point discrimination
- Vibration
- Proprioception
Where does the first order neuron synapse with the second order neuron in the dorsal column?
Medulla Oblongata
The fibres also immediately decussate here
What part of the dorsal column transmits sensation for the lower body?
Fasciculus/Nucleus Gracilis
What part of the dorsal column transmits sensation for the upper body?
Fasciculus/Nucleus Cuneatus
For both of the ascending pathways where do the second order neurons synapse with third order neurons?
Thalamus
For both ascending pathways where do third order neurons travel?
Somatosensory complex in post-central gyrus
What is the medial lemniscus?
Term that describes the decussation of fibres in the dorsal column at the medulla oblongata
What sensations are transmitted via the lateral spinothalamic tract (LST)?
- Pain
- Temperature
What sensations are transmitted via the Anterior spinothalamic tract (AST)?
- Crude touch
- Pressure
Where do first order neurons from the lateral spinothalamic tract synapse with second order neurons?
substantia gelatinosa
Where do first order neurons from the anterior spinothalamic tract synapse with second order neurons?
Nucleus proprius
Name the descending tracts?
- Corticospinal (pyramidal) tract
- Tectospinal tract
- Reticulospinal tract
- Vestibulospinal tract
What is the function of the corticospinal tract?
Fine, precise movement especially that of distal limb muscles.
Where do the pyramids in the corticospinal tract form?
The medulla, This is also where 85% of the fibres decussate to form the lateral corticospinal tract
What name is given to uncrossed corticospinal fibres?
Ventral corticospinal tract
What area is innervated by the Lateral corticospinal tract?
Limbs
What area is innervated by the ventral corticospinal tract?
Trunk, neck & shoulders
What is the tectospinal tract responsible for?
Mediation of head and neck movement
What is the reticulospinal tract responsible for?
Mainly influence over voluntary movement
Fibres from the medial (pons) part of the reticulospinal tract mediate what?
Extensor movement of trunk and limbs
Fibres from the lateral (medulla oblongata) part of the reticulospinal tract mediate what?
Flexor movement of trunk and limbs
What is the vestibulospinal tract responsible for?
Facilitating extensor muscles
