Ascending Sensory Pathways Flashcards
Somaesthetic modalities essential for survival
Conduction speed/what type of fibres
Pain, Temperature, Touch, some pressure
Thin, Poorly Myelinated Fibres
Slow Conduction
Somaesthetic Modalities that increase detail
Conduction speed/what type of fibres
2 Point Discrimination and vibration, Proprioception
Fat, heavily myelinated fibres
Fast conduction
Somaesthetic modalities carried in Spinothalamic Pathway
Pain, Temperature, Touch, some pressure
Somaesthetic modalities carried in Dorsal Column Pathway
2 Point Discrimination and vibration, Proprioception
Primary Neuron in sensory chain
Sensory Receptor to Ipsilateral CNS
Secondary Neuron in sensory chain
Ipsilateral CNS to Contralateral Thalamus
This neurone always responsible for decussating the SC- where this occurs depends on the pathway
Tertiary Neuron in sensory chain
Thalamus to Post-Central Gyrus via the Posterior limb of Internal Capsule
Modifications of neurons in pathway
Other inputs
1:Many or Many:1 depending on nature of information
At which level does the Secondary Neuron cross the midline in the Spinothalamic Pathway
Level of Entry into SC (via Ventral White Commissure)
Where does the Spinothalamic Tract become known as the Spinal (Lateral) Lemniscus
Medulla
Somatotopic Mapping of the Spinothalamic Tract?
Arm Ventrally
Trunk Medial
Leg Dorsally
Which nuclei does Sensory from Legs go to in the Thalamus?
Lateral VPL Nucleus
Legs are Lateral
Which nuclei does Sensory from Arms go to in the Thalamus?
Medial VPL Nucleus
Which nuclei does Sensory from the Face go to in the Thalamus?
VPM Nucleus
Where in the Cortex does the Lateral VPL Nucleus ( sensory from legs) project?
Medial Primary Motor Somatosensory Cortex
within great longitudinal fissure
Where in the Cortex does the Medial VPL Nucleus (sensory from arms) project?
Mid- Lateral Primary Somatosensory Cortex
between legs and face mapping
Where in the Cortex does the VPM Nucleus (sensory from face) project?
Lateral Primary Somatosensory Cortex
Where does the Primary Neuron in the Dorsal Column Pathway run?
Gracile or Cuneate Tubercles to Gracile and Cuneate Fascicles
Above which vertebral level is the Gracile Tubercle present?
T6
Where does the Gracile Tubercle carry sensory information from?
Lower Trunk, Lower Limb
Where does the Cuneate Tubercle carry sensory information from?
Upper Trunk, Upper Limb
Where are the Gracile/Cuneate Fascicles (Nuclei) located?
Closed Medulla
How does the Secondary neurone in the Dorsal Column Pathway travel to the Thalamus?
Crosses the midline in closed Medulla as Internal Arcuate Fibres
Travels to Thalamus in Medial Lemniscus
Somatotopic mapping of the Medial Lemniscus?
Legs Ventral (Just below Pyramids)
Trunk Medial
Arm Dorsal
