Ascending Sensory Pathways 1 Flashcards
What type of information does the spinothalamic pathway carry?
Pain
Temp
Touch
What type of information does the dorsal column pathway carry?
Touch
Vibration
Pressure
Proprioception
What are the two groups that somaesthetic modalities fall into and which pathway belongs to which group?
Essential to survival - STT
Those that increase detail - DCP
What are the characteristics of the fibres in the DCP?
Large diameter
Heavily myelinated so fast conduction
What are the characteristics of the fibres in the STT?
Thin
Poorly myelinated or unmyelinated so slow conduction
What is a pseudounipolar neruron?
A neutron with a single stalk that splits to give off two processes
How many neurons make up the general sensory pathways?
3: first, second and third order
Where do the cell bodies of 1st order neurons reside?
DRG
Does the DRG belong to the CNS or PNS?
PNS
Which cell bodies reside in the CNS Ipsilateral grey matter?
Cell bodies of 2nd order neurons
What do the axons of 2nd order neurones do?
Cross the midline and ascend to the thalami
Where do cell bodies of 3rd order neurones reside?
Thalamus
Where do the axons of third order neurons project?
Somatosensory Cortex
Which lobe is the post central gyrus located in?
Parietal
What comprises the Dorsal Column?
Gracile and Cuneate Fasiculi
What happens to STT fibres BEFORE they contact secondary neurons?
They ascend 1-2 segments
Where does the synapse between primary and secondary neurons, in the STT, occur?
In the dorsal grey horn
Where does the secondary axon cross in the STT?
Crosses the midline in the ventral white commisure
Which regions of the spinothalamic tract, medial to lateral, receive sensory input from which regions of the body?
Medial: Arm
Trunk
Lateral: Leg
What is the region called in which the STT fibres ascend to the thalamus?
Spinal or Lateral Lemniscus
Which pathway contains fibres which ascend contra laterally?
STT
Which pathway contains fibres which ascend ipsilaterally?
DCP
What is the significance of T6 in the anatomy of the DCP?
Sensory input above T6 synapses in the cuneate fascicle
Sensory input below T6 synapses in the gracile fascicle
Which brainstem level do the fibres of the DCP cross the midline?
Closed Medulla
