Ascending Pathways Flashcards
What are ascending pathways?
Pathways of general sensation carrying impulses from peripheral receptors to the brain
What are the types of fibres found in white matter of the spinal cord
3 types- ascending, descending and intersegmental
Which sensory pathways carry general sensation from below the neck?
The posterior column and spinothalamic pathways
Which sensory pathway carries general sensation from the head and neck?
The trigeminothalamic pathway
What is a lemniscus?
The second order neuron tracts in brainstem
Where do the second order neuron tracts end?
The thalamus
Where are the cell bodies of second order neurons located?
The grey matter of spinal cord
Where are the cell bodies of the 3rd order neurons located?
The thalamus
Where are the tracts of the posterior column pathway located?
Between the posterior horn of grey matter and the posterior median septum of spinal cord
Where do neurons supplying the lower trunk ascend?
fasiculus gracillis
Where do neurons supplying the upper trunk ascend?
fasiculus cuneatus
Where do tracts of the spinothalamic pathway lie?
Lateral and anterior to anterior horns of grey matter
What information does the spinothalamic pathway carry?
pain, temperature and non-discriminative touch (pressure)
What are the the 3 main sensory parts of the trigeminal nerve
mesencephalic (midbrain), principal (pons) and spinal nucleus (medulla)
What does the mesencephalic nucleus of trigeminal nerve serve?
proprioception
What does the principal nucleus of trigeminal nerve serve?
fine and crude touch
What does the spinal nucleus of trigeminal nerve serve?
pain and temperature
Where are cell bodies of first order neuorns of trigeminothalamic tract located?
The trigeminal ganglion
Where do 2nd order neurons of posterior column begin?
The gracile and cuneate nuclei
What do the 2nd order neurons of the posterior column cross the midline as?
Internal Arcuate fibres
Where do each medial leminscus terminate?
Lateral part of Ventral Posterior Nucleus of Thalamus
What does anterior part of spinothalamic tract do in midbrain?
Merges with medial lemniscus
What does the lateral part of spinothalamic tract become in midbrain?
Spinal lemniscus
What do A delta fibres conduct?
Temperature and ‘fast pain’
What do C fibres conduct?
‘Burning’ pain
Where does the trigeminla lemniscus terminate?
Ventral posterior medial nucleus of thalamus
