Ascending Sensory Pathways

Question 1

Somaesthetic modalities essential for survival

Conduction speed/what type of fibres

Answer 1

Pain, Temperature, Touch, some pressure

Thin, Poorly Myelinated Fibres

Slow Conduction

Question 2

Somaesthetic Modalities that increase detail

Conduction speed/what type of fibres

Answer 2

2 Point Discrimination and vibration, Proprioception

Fat, heavily myelinated fibres

Fast conduction

Question 3

Somaesthetic modalities carried in Spinothalamic Pathway

Answer 3

Pain, Temperature, Touch, some pressure

Question 4

Somaesthetic modalities carried in Dorsal Column Pathway

Answer 4

2 Point Discrimination and vibration, Proprioception

Question 5

Primary Neuron in sensory chain

Answer 5

Sensory Receptor to Ipsilateral CNS

Question 6

Secondary Neuron in sensory chain

Answer 6

Ipsilateral CNS to Contralateral Thalamus

This neurone always responsible for decussating the SC- where this occurs depends on the pathway

Question 7

Tertiary Neuron in sensory chain

Answer 7

Thalamus to Post-Central Gyrus via the Posterior limb of Internal Capsule

Question 8

Modifications of neurons in pathway

Answer 8

Other inputs

1:Many or Many:1 depending on nature of information

Question 9

At which level does the Secondary Neuron cross the midline in the Spinothalamic Pathway

Answer 9

Level of Entry into SC (via Ventral White Commissure)

Question 10

Where does the Spinothalamic Tract become known as the Spinal (Lateral) Lemniscus

Answer 10

Medulla

Question 11

Somatotopic Mapping of the Spinothalamic Tract?

Answer 11

Arm Ventrally
Trunk Medial
Leg Dorsally

Question 12

Which nuclei does Sensory from Legs go to in the Thalamus?

Answer 12

Lateral VPL Nucleus

Legs are Lateral

Question 13

Which nuclei does Sensory from Arms go to in the Thalamus?

Answer 13

Medial VPL Nucleus

Question 14

Which nuclei does Sensory from the Face go to in the Thalamus?

Answer 14

VPM Nucleus

Question 15

Where in the Cortex does the Lateral VPL Nucleus ( sensory from legs) project?

Answer 15

Medial Primary Motor Somatosensory Cortex

within great longitudinal fissure

Question 16

Where in the Cortex does the Medial VPL Nucleus (sensory from arms) project?

Answer 16

Mid- Lateral Primary Somatosensory Cortex

between legs and face mapping

Question 17

Where in the Cortex does the VPM Nucleus (sensory from face) project?

Answer 17

Lateral Primary Somatosensory Cortex

Question 18

Where does the Primary Neuron in the Dorsal Column Pathway run?

Answer 18

Gracile or Cuneate Tubercles to Gracile and Cuneate Fascicles

Question 19

Above which vertebral level is the Gracile Tubercle present?

Answer 19

T6

Question 20

Where does the Gracile Tubercle carry sensory information from?

Answer 20

Lower Trunk, Lower Limb

Question 21

Where does the Cuneate Tubercle carry sensory information from?

Answer 21

Upper Trunk, Upper Limb

Question 22

Where are the Gracile/Cuneate Fascicles (Nuclei) located?

Answer 22

Closed Medulla

Question 23

How does the Secondary neurone in the Dorsal Column Pathway travel to the Thalamus?

Answer 23

Crosses the midline in closed Medulla as Internal Arcuate Fibres

Travels to Thalamus in Medial Lemniscus

Question 24

Somatotopic mapping of the Medial Lemniscus?

Answer 24

Legs Ventral (Just below Pyramids)
Trunk Medial
Arm Dorsal