Ascending and Descending Tracts Flashcards
Name 3 ascending tracks
Lateral spinothalamic
Anterior (ventral) Spinothalamic
Dorsal columns (medial lemniscus)
Name 2 descending tracts
Lateral corticospinal
Anterior corticospinal
What information does the lateral spinothalamic tract carry
Pain
Hot/cold of the limbs and trunk
What type of receptors are in the lateral spinothalamic tract
free nerve endings
What type of fibers transmit sharp pain?
slow/dull pain?
A-delta
C Fibers
Where does the lateral spinothalamic tract ascend?
where does it cross?
where does it terminate?
Ascends in lateral white column of SC
Crosses within 1-2 segments (cross SC almost immediately)
Terminates in parietal lobe
What information does the Anterior (ventral) spinothalamic tract carry
Crude touch and pressure
What type of receptors are in the anterior (ventral) spinothalamic tract
Merckel’s discs
Ruffini corpuscles
free nerve endings
Where does the anterior (ventral) spinothalamic tract ascend?
where does it cross?
where does it terminate?
Ascends in anterior white column
Crosses within 1-2 segments (almost immediately)
Terminates in parietal lobe
What information does the Dorsal columns (medial meniscus) carry
- 2 point discrimination
- Fine touch
- Stereognosis
- Vibration
What type of receptors are in the Dorsal columns (medial meniscus) tract
Pacinian Corpuscles (vibration
Merckel’s disc
Meissner’s (light touch)
A-beta
where does the Dorsal columns (medial meniscus) tract cross?
where does it terminate?
Cross in brain stem
Terminate in parietal lobe
Why do the ascending tracts all terminate in the parietal lobe
this lobe integrates sensory information from different modalities
With Brown sequard syndrome lesion of half the cord - is the pattern of loss of the 3 ascending tracts
Lateral and anterior spinothalamic: ipsilateral loss at the level and contralateral loss below the lesion
Dorsal columns: Ipsilateral loss
What is the pattern of loss of the Dorsal columns with a lesion above the medulla
Contralateral loss
